Linear Motion Lab Essays

Linear Motion Lab Essays Linear Motion Lab Paper Linear Motion Lab Paper 2. LINEAR MOTION In this experiment you will study the motion of an object in one dimension from a number of points of view. You will demonstrate how the variables of motion are related by differentiation and integration and investigate the relationship between potential and kinetic energy. Theory Why Study Motion? Motion is everywhere in the universe. Only at a temperature of absolute zero is the motion in any body truly absent. If motion exists then so also does energy. To the delight of the modern-day physicist the tools that were invented by Galileo Galilei, Isaac Newton and others 200 years ago to describe motion apply everywhere in the universe, from electrons in our own bodies to the farthest galaxy. The study of motion and of energy is at the heart of physics. This experiment deals with motion of the simplest kind, motion in one dimension or motion in a straight line. Kinematics and Dynamics The subject of motion is divided for convenience into the subtopics of kinematics and dynamics. Kinematics is concerned with the aspects of motion that exclude the forces that cause motion. In a manner of speaking, kinematics is focussed on the development of definitions: position, displacement, velocity, acceleration and on the relationships that exist between them. Dynamics widens the study of motion to include the concepts of force and energy. Definitions Position Kinematics begins with the idea of position. Suppose that we photograph an object moving to the left along a horizontal path at two instants of time and superimpose the images for study (Figure 1). We examine one image with a ruler and mark off the number of units that separate the object from the ruler’s zero. The zero is a reference or origin at a position of zero units by definition. The position of the object at any another place is, say x units. x is an instantaneous quantity since it applies to a specific clock time- the instant the photograph was taken. Position like length is a basic quantity and is dependent only on the unit used. But position involves direction also. In principle the object could be to our right or to our left. To include the information of direction we use a vector. The magnitude or length of the vector, say r, is r (or perhaps x), while the direction is to the right, meaning the object is to the right of the reference point. We could also agree that, by convention, the sign of x is positive in this particular case. Elapsed Time The two positions of the object in Figure 1 must be described with different vectors and different clock times. The photographs can be said to show two events, an initial â€Å"i† event and a final â€Å"f† event. There is now an elapsed time between the events equal to the simple difference: ?t = t f – t i , †¦[1] unit seconds, abbreviated s). Keep in mind that the concepts of clock time and elapsed time are different; an elapsed time is the difference between two clock times. L2-1 L2 Linear Motion 0 rf clock time tf object ri displacement ? r = rf – ri clock time ti object ? r = v ? t Figure 1. This drawing illustrates an object moving toward the origin (left) â€Å"photographed† at two positions. The corresponding clock times are indicated. Position, displacement and velocity vectors are given different head styles to emphasize their different natures. Displacement Displacement differs from position. In the elapsed time between the events the object moves from one position to another. The displacement is the difference between the two vectors describing the two positions: d. Eq[3] then becomes what is known as the instantaneous velocity ? dr ? =v. dt †¦[4] ? ? ? ? r = rf – ri , †¦[2] (unit meters, abbreviated m). Displacement, being the difference between two vectors, is also a vector. The displacement is negative in this case (according to our convention) since it points towards the origin. Velocity Average Velocity. Another quantity in kinematics is the average velocity. This is the displacement an object undergoes in one second of elapsed time. It is the ratio ? ? This quantity is abstract and tricky to imagine: it can be thought of as the average velocity that might be measured with a superior detection system over an infinitely short elapsed time (or the velocity at a specific clock time). In practice, with equipment available in a first year physics lab, it can be measured only approximately. If the displacement is known as an analytical function of time, r(t), then the instantaneous velocity at some clock time t0 is the tangent to the function at t0, or the first derivative of r(t) at t0. The finding of tangents is one of the objectives of this experiment. Acceleration The velocity of the object in Figure 1 may change with time. The velocity might decrease as a result of a force of friction between the object and the path. Or the velocity might increase if the path were not horizontal and a component of the force of gravity acts on the object. The time rate of change of the average velocity is called the average acceleration and the time rate of change of the instantaneous velocity is called the instantaneous acceleration. Both types of acceleration are defined as in eqs[3] and [4] with â€Å"v† subsituted for â€Å"r â€Å"and â€Å"a† substituted for â€Å"v†. ? ? r rf – ri ? = =v, ? t ? t †¦[3] (unit meters per second, abbreviated m. s–1). The average velocity, being a vector divided by a scalar, is a vector. The average velocity is negative here, too, since it points towards the origin. The magnitude of the average velocity is the speed. The elapsed time in eqs[1] and [3] is a finite interval. What would happen if this interval were infinitely small? Mathematically speaking, this amounts to taking the limit of eq[3] as ? t>0. The increments ? ust be replaced by the differentials L2-2 Linear Motion L2 Motion of an Object Whose Velocity is Constant In this experiment you will mostly be studying the motion of an object whose velocity is changing. However, for purposes of completeness we first consider motion at constant velocity. The case of an object moving t owards the origin on a horizontal plane is drawn in Figure 2. We suppose that the data pairs (t, r), where t is the clock time and r is the position are measurable at regular intervals by some detection system. Two such points when plotted on a graph might appear as shown in the upper half of Figure 3. A computer could be programmed to calculate the â€Å"average velocity† as the slope between the two datapoints and plot it as a point on a graph (lower half of Figure 3). The result is negative, the sign indicating the direction of the velocity vector. The computer software used in this experiment does something similar by finding the average velocity by averaging over the slopes between a number of datapairs (7 by default). Thus if a number of datapoints were measured and the results plotted on a graph, the result might resemble Figure 4. As the glider approaches the origin here the position decreases but always remains positive. The velocity remains at a constant negative value. The velocity is therefore just the derivative or the slope of the displacement versus clock time graph (or the slope of the position versus clock time graph here in one dimension). The velocity is seen to change little (if at all) with clock time and so the acceleration (decceleration) is very small. Motion Detector 0 clock time: tf rf clock time: ti ri positive displacement ? r = rf – ri v = ? r also to the left ? t Figure 2. An object is shown at two positions (events) while moving toward a detector on a horizontal plane. ti , ri ) Position ( tf , rf ) clock time Velocity ( tf , vf ) Figure 3. A graph of the two position-clock time datapoints described in Figure 2. Shown also is a point on the velocity graph as it might be generated from the slope between the two datapoints multiplied by the sign of the velocity vector. L2-3 L2 Linear Motion Figure 4. Typical position and velocity graphs as might be produced for an object mo ving as shown in Figure 2. Can you see how these graphs are consistent with Figure 3? Motion of an Object Whose Velocity is Changing with Time In this experiment you will mostly be ignoring the effects of the force of friction. However, for purposes of understanding it is useful to consider friction briefly. A small force of friction must exist between the glider and the layer of air on which it moves because the glider is seen to slow down. Friction acts opposite to the direction of motion (to the right in Figure 2) and therefore produces an acceleration also toward the right. This acceleration is often described as a decceleration in the sense that it is opposite to the velocity and describes a velocity decrease. (The object is slowing down. The velocity and acceleration versus clock time graphs in this case will resemble Figure 5. It is known from other experiments (â€Å"Simple Measurements†) that the force of friction, though small, has a complicated functional form giving rise to a decceleration that depends on the first (and sometimes the second) power of the speed. Gravity, unlike friction, is a constant forc e and is therefore much easier to deal with; the effect of gravity on motion we consider in the next section. Figure 5. Velocity and acceleration graphs for an object moving as shown in Figure 2 while subject to a small force of friction. Remember, graphed here are the magnitudes of the vectors multiplied by the sign corresponding to the direction of the vectors. Motion of an Object Whose Acceleration is Constant and Nonzero An object moving with constant non-zero acceleration down an inclined plane (neglecting friction) is shown in Figure 6. Its free body diagram is drawn in Figure 6b. Starting from the assumption that the acceleration is constant and nonzero we can develop the mathematics of the object’s motion using successive integration. If friction is negligible, then the L2-4 Linear Motion L2 agnitude of the force giving rise to the object’s movement is the component of the force of gravity along the incline, that is, where C2 is another constant of integration. C2 = r(0), the position at a clock time of 0 seconds; thus F = ma = –mgsin ? , †¦[5] r(t) – r(0) = 1 2 at + v(0)t . 2 †¦[9] where the minus sign means that the force vector points towards the origin. The glider†™s instantaneous speed at some arbitrary clock time t is obtained by integrating a from eq[5]: 1 v(t) = ? adt = at + C1 , where C1 is a constant of integration. C1 is the instantaneous speed at a clock time of 0 seconds, i. . , the quantity v(0); thus We can now make the following correspondence. If at event i we let ti = 0, then ri = r(0) and vi = v(0). Then we can also write for the event f, tf = t, rf = r(tf) and vf = v(tf). Then equations [9] and [7] take on the more familiar forms: rf – ri = and 1 2 at – v it 2 †¦[10] †¦[11] v f = vi + at . v(t) = v(0) + at . †¦[7] The glider’s position at the clock time t is found by integrating v(t) from eq[7]: r(t) = ? v(t)dt , = ? (at + v(0))dt , = 1 2 at + v(0)t + C2 , 2 †¦[8] In this experiment you can test these equations with the detection system and software several ways. Firstly, you can test if the position, velocity and acceleration data you collect really is described by functions of the form of eqs[10] and [11]. In other words, you can perform polynomial â€Å"fits† to the data, finding in the process the value of a. You can test the differential and integral relationships between the variables by invoking the options of slope and integral. These are some of the objectives of this experiment. ti , vi tf , vf Motion Detector rf m g sin ? 0 ? ? r = rf – ri (a) (b) ri posi tive N mg Figure 6. (a) A object is shown at two positions while moving down an inclined plane. The object’s free body diagram is shown in (b). The object is â€Å"pulled† toward the origin by the component of the force of gravity mgsin?. The acceleration is negative here according to the sign convention employed by the detection system. L2-5 L2 Linear Motion Work and Mechanical Energy In Figure 6 the object is shown moving down an inclined plane. It is therefore accelerating. Any time an object is accelerating, work is being done upon it. The concepts of force and energy take us in this section into the area of dynamics. The concepts of work and energy are closely related. The work done on a point mass2 by a net constant force F is defined Work-Energy Theorem the work done on an object goes to increase the object’s mechanical energy. This energy can be either kinetic energy, potential energy, or both. Both types of energy can be defined with reference to Figures 7 where an object of mass m is shown responding to an applied force in two ways. In Figure 7a the object is being moved to the left in our field of view along a horizontal, frictionless surface. In Figure 7b the object is being moved vertically upwards. Figure 7a enables us to define kinetic energy most easily. Figure 7b enables us to define potential energy. We first consider the former in the next section. ? ? W = F r = Frcos ? , †¦[13] (unit joules, abbreviated J). Here r is the object’s displacement vector and ? is the angle between the vectors F and r. (The symbol indicates the scalar or â€Å"dot† product of vectors. ) According to the F m hf Fg ? v = 0 F speed vf m ? h = 0 F speed vi m ? h reference position m Fg Figure 7. An object is shown responding to a force in two ways. In (a) the surface is horizontal and frictionless, so the work done by the source of the force F goes entirely into increasing the object’s kinetic energy. In (b) F is greater then the weight | F g | of the object by some infinitesimal amount so the work done by the source of the force goes entirely into increasing the object’s potential energy. F (a) hi (b) L2-6 Linear Motion L2 Kinetic Energy Suppose (Figure 7a) that we are able to measure the instantaneous speed of the object at the clock times ti and tf when the object is at positions ri and rf, respectively. The object is receiving a force F and is being accelerated. In general, F is not constant. The work done on the object between ri and rf is, from a generalization of eq[13] 3 1 1 = m? v 2 – vi2 ? . f ? 2 ? The work done is therefore the difference between two terms: W= 1 2 1 2 mv – mv . 2 f 2 i †¦[14] ? ? ? ? W = ? F dr = m? a dr = m? adr , since the vectors a and dr are parallel. Changing the variable of integration from r to v gives 4 If we call the expression mv2/2 the kinetic energy Ek, or the energy of motion, eq[14] can be written W = Ekf †“ Eki = ? Ek . †¦[15] dv dr ? , W = m? ? ? dt dt dt ? = m? v vdv , i vf In this particular case W is a positive number, i. e. , the kinetic energy of the object is increasing. The work done on the object is therefore equal to this increase in kinetic energy. This is one-half of the Work-Energy Theorem. Potential Energy If we assume in Figure 7b that the magnitude of the applied force F is insignificantly greater than the weight of the object acting downwards then the object moves upwards a distance ? h = hf – hi in some elapsed time at zero speed (thus acquiring negligible kin-etic energy). From the definition, eq[13], the work done on the object is W = E pf – Epi = ? Ep . †¦[17] ? ? W = ? F dr , = ? h mgdr . i hf Once again the work done is seen to be equal to the difference between two terms: W = mghf – mghi . †¦[16] If we call the expression mgh the potential energy of the object at the position h relative to the position 0 and denote it Ep we can write eq[16] as This is also a positive number. Thus the work done on the object is equal to the increase in the object’s potential energy. This is the second half of the Work-Energy Theorem. The change in kinetic energy is zero here. This energy is potential energy, gravitational potential energy to be exact. This is the energy an object possesses by virtue of its position relative to some reference position in a gravitational field. This energy is the work required (by us) to move the object (very slowly) to the final position from the initial, reference position. Now Figures 7 describe two idealized situations where the object is moving either horizontally or vertically. Should the object be moving on an inclined plane it will be moving at an acute angle relative to the horizontal and will therefore undergo changes in both kinetic and potential energy. One of the objects of this experiment is to study this general case. L2-7 L2 Linear Motion The Experiment Exercise 0. Preparation First Steps Identify the glider stowed on top of your air blower. Find the spacer. Identify the detector (the blue box) mounted just beyond the near end of the track) and the universal interface (ULI) board mounted on the front of the blower box. Simple Measurements You are going to log the glider’s mechanical energy so you need its mass. You can weigh it on one of the electronic balances in the lab. Measure the thickness of the spacer with the vernier caliper. The Air Track The object whose motion you will study is a glider on an air track (Figure 8). An air track is an ideal device for studying the motion of an object like a glider since it supplies a thin film of air on which a glider, having just the right shape, can move with reduced friction. Identify the air track’s two rear feet and its single front foot. Confirm that elastic bands are in place to serve as bumpers for the glider. The detector and associated electronics in the ULI board log the glider’s position at clock times you can select. The detector emits pulses of ultrasound at a frequency of 50 kHz. These pulses travel out from the detector through the air, reflect from the reflector on the glider and then return. Since the speed of ultra-sound in air at room temperature is known, the computer is able to calculate the distance of the glider from the detector (the position) by timing the round trip of the pulse. 5 To get velocity and acceleration, the computer makes several measurements and calculates averages and rates of change. Motion Detector near bumper far bumper single front spacer goes under front footpad ? X = (2. 29  ± 0. 01) m spacer Y Figure 8. The air track shown in an inclined position (scale is exaggerated here). X is the distance between the single front foot and the midpoint of the two rear feet. For all tracks X = (2. 29  ± 0. 01) m. L2-8 Linear Motion L2 Checks to Minimize Friction To ensure that your glider moves with minimum friction check the following: Motion setup should run. The Opening Screen The opening screen shows three narrow graph areas (one of which is shown in Figure 10). The position versus clock time graph should be currently selected (a box should be drawn around it). To select any graph move the mouse to position the cross-hair pointer over the graph and then click the mouse button once. Notice on the clock time axis of the graphs that the program is set by default to record for 10 seconds. The Expected Value of Acceleration Locate the spacer you will be placing under the front footpad of your track. Based on the geometry of Figure 8 what value of acceleration should you expect for your glider? You need this number in the formula for potential energy (next section). Entering Formulas LoggerPro automatically computes velocity and acceleration from the basic values of position it records, but it must be instructed to calculate energy (since energy depends on your glider’s mass). You have to enter the formulas into LoggerPro’s spreadsheet. To do this select Data New Column Formula. Figure 9 shows a fragment of the screen which then appears. On separate calls to New Column enter formulas for kinetic energy, potential energy and total energy as is shown in the figure. Pay attention to the common spreadsheet syntax (â€Å"*† means multiply, â€Å"^† means to the power of, etc. ) Notice that you can select variables and functions from the popdown lists. You enter velocity as â€Å"Velocity† which you can either type in yourself or select from the Variables popdown list. Take your time here. Your TA will help you with these tasks. The formula you will likely have the most difficulty with is potential energy. Convince yourself the formula can be written ? Ep = m x (expected value of a) x position. Or, in LoggerPro notation: ? If ON, turn any and all equipment OFF. ? In order to run properly, the â€Å"V† angle of your glider must match the â€Å"V† angle of your track. Read and follow the instructions on the blower box. Turn the air blower ON. In order to run properly, your glider must be supported by air at sufficient pressure. Read and follow the instructions on the blower box. ? ? Level Check Your air track must be level when you start this experiment otherwise your glider will experience an unaccounted for acceleration. To check for level first remove any spacer that might have been left under the front footpad of the track. Place your glider on the midpoint of the track and look for any drifting right or left. If your glider does drift adjust the screw on the front foot of the track to compensate. When the track is level your glider should not drift appreciably left or right. Setting up the ULI Board Turn the ULI board ON by means of the switch located in its lower right hand corner. A LED on the board should glow red or green. ? Booting LoggerPro To boot the program follow these steps: ? With the computer ON log into your account n the FISSURE server as you learned to do at the Orientation Workshop. (If for any reason you cannot log in you can save your work temporarily in the â€Å"Student Temp Save† folder on the local hard drive. In any case, you can log in and out at any time. ) On the local harddrive â€Å"Macintosh HD†, locate and open folders in this order: â€Å"Physics† †PHYA10 †02. Linear Motion†. Inside â€Å"02. Linear Motion† double click the icon Linear Motion. LoggerPro and the Linear ? ? L2-9 L2 Linear Motion m * (expected value of a) * â€Å"Position†. What is the expected value of â€Å"a† based on a 2 cm spacer? If later, you find you have made a mistake in typing and wish to modify or remove the column go back to Data Modify Column and correct your mistake. When ready click OK. Changing the Graph in an Area By the time you have finished entering these formulas you may observe that the label down the left hand side of the graph has changed (look ahead to the left hand side of Figure 10). You can change what is displayed in a graph area. To do this place the pointer over the label and hold down the mouse button. You can then select the graph you wish from the list of Columns to Plot. Do this now to change the label on the first graph back to r (m). Figure 9. A fragment of the screen which appears when you select New Column. Exercise 1. First Launch, More Options and First Observations The objective of this exercise is to obtain some data from a first launch, to explore a few options of the program and to examine the data qualitatively. First Launch After you have levelled your air track to your satisfaction place the spacer under the front footpad of the track. The track is now inclined by some angle. Now release (don’t push) the glider from the top end of the track. Make sure the glider’s reflector is facing the motion detector. It is suggested that you record data between two bumps of the glider with the lower end of the track. When you are ready, click the Collect button. Repeat a few times to get graphs to your liking. After 10 seconds you should see screens resembling Figure 10. You should have 6 graphs of information altogether: Position, Velocity, Acceleration, Kinetic Energy, Potential Energy and Total Energy (the last three you have to select using Option 1 below). Before you get down to serious business you may wish to investigate one or more of the following options. However, if you wish to bypass the options you can go directly to the section First Observations. Option 1. Changing the Graph in an Area Notice in Figure 10 the label â€Å"r (m)†. You can L2-10 Linear Motion L2 change what is displayed in a graph area. To do this move the mouse to place the pointer over the label and hold down the mouse button. A list of Columns to Plot will then pop down. Select the graph you wish to be displayed in the area from this list. Option 2. Number of Panes You may wish to display one graph at a time or as many as four graphs. To change the number of panes select View Graph Layout†¦. Then click on the number of panes selection you wish. Graph produced by LoggerPro, copied to the clipboard and pasted directly into Microsoft Word. Figure 10. A Position vs time graph. This is one of the six screens of information you have collected at this stage of the experiment. Option 3. Saving If you wish to save your experiment choose File Save As†¦. Make sure you save your file in your account space on the campus server or in the â€Å"Student Temp Save† folder on the local hard drive. Option 4. Preparing for Printing Eventually, you will want to print your graphs on the laserwriter printers in the physics lab as proof of your work. To prepare for printing, choose File Page Setup. Fill in your name and any comment you wish to have appear beneath your graphs on the printed page and then click OK. Your partner may change this later to print graphs for his or herself. Option 5. Printing Before you attempt to print anything on the laserwriter printers in the physics lab, confirm that your output will go to the printer you expect. Select Chooser LaserWriter 8, then confirm that the correct printer (Physics LaserWriterI or PhysicsLaserWriter2) is selected. If in doubt about a printing issue ask your TA. To actually print a graph choose File Print Graphs. First Observations Before you apply mathematics to your data in any experiment it is often useful to obtain an overall qualitative â€Å"impression† of your data to determine if it is â€Å"reasonable†. To this end consider these questions: Questions: ? With reference to eqs[10] and [11] do you have a graph which is quadratic in time? Linear in time? Which graph describes a constant (between bumps)? ? Your position versus clock time graph resembles the path of a projectile in two dimensional space. Why? ? Explain in your own words why the velocity and acceleration graphs have the form you observe. ? From your velocity versus clock time graph you should be able to find a clock time at which the velocity of the glider was zero. What L2-11 L2 Linear Motion was the acceleration of the glider at this clock time? If the velocity of a body is zero can its acceleration be non-zero? Explain. With LoggerPro’s tools you can call up instantaneous values and tangents. To see instantaneous values choose Analyze Examine. One of the graphs will resemble Figure 11. If you now choose Analyze Tangent the tangent or slope at the position of the cursor will be shown on the graph. By means of the tangent function can you demonstrate to your satisfaction the validity of eq[4] and its counterpart for acceleration? A few tests are sufficient because you will continue this study in Exercise 3. When you wish to turn Analyze OFF choose Analyze Examine a second time. A better test of the validity of eqs[10] and [11] is a polynomial fit. This you will do in the next exercise. Graph produced by LoggerPro, copied to the clipboard and pasted directly into Microsoft Word. Figure 11. One of the six graph screens with Examine turned on. As you move the cursor with the mouse the position and time are updated at the top left corner of the screen. Exercise 2. Fitting Functions to Data The objective of this exercise is to test the validity of eqs[10] and [11] by seeing if they can be fitted to the appropriate set of your data, position, velocity or acceleration. The result of the fitting will yield the acceleration â€Å"a†. This value you can then compare with the â€Å"expected value† of Exercises 0 and 1. Fitting To fit a function to your data first select (click on) the appropriate graph. Then choose Analyze Examine. Place the cursor at the beginning of the range you wish to fit, hold down the mouse button and drag over the range you wish fitted. Make sure the range you select does not include a bump (after all, you are interested in linear motion and a bump is defnitely non-linear). If you wish to fit a straight line choose Analyze Linear Fit. If you wish a different kind of fit (a quadratic for example) choose Analyze Curvefit. The result of a linear fit might appear as shown in Figure 12. For this process to succeed you must pay close attention to the function to be fitted and the terms to be included. For example, eq[11] is what kind of function of time? Linear? Quadratic? What is the slope? What is the intercept? If you wish more information on the linefit (more digits etc) double click on the bar of the information window. The result will resemble Figure 13. L2-12 Linear Motion L2 Fit Results Find the acceleration â€Å"a† from the results of the fit of all three graphs (position, velocity and acceleration). How do the a alues compare with each other and with the expected value? Comment on the quality of the fits. If the fits are good it can be said that the equations â€Å"describe† the data. Graph produced by LoggerPro, copied to the clipboard and pasted directly into Microsoft Word. Figure 12. A range of data on a velocity vs clock time graph has been selected (shown by the square brack ets) and fitted to a straight line. To request more information about a fit double click on the bar of the fit information window (Figure 13). Graph produced by LoggerPro, copied to the clipboard and pasted directly into Microsoft Word. Figure 13. The graph of Figure 12 showing more information about the linefit. The slope is now seen to be -0. 0897  ± 0. 0001. Cor is the correlation coefficient. Exercise 3. Differentiation and Integration The objective of this exercise is to investigate how the variables of motion are related by differentiation and integration. Differentiation (Slope Studies) Identify the sections on the position versus clock time graph where the glider is moving towards and away from the origin. Explain in your own words why the position increases or decreases and when. Is the value obtained for the slope of the position versus clock time graph at some arbitrary clock time consistent in magnitude and sign with the value given for the velocity? Is the value obtained for the slope of the velocity versus clock time graph consistent in magnitude and sign with the value given for the acceleration? A few tests will suffice. L2-13 L2 Linear Motion Integration (Area Studies) Comparing two variables of motion related by differentiation- when one is the slope of the clock time graph of the other- is easy. But what if the relation is integration? To prepare ourselves we put eqs[9] and [10] in this form: (t 2 ) – r(t1 ) = ? t v(t)dt , 1 t2 †¦[18] where t1 and t2 are, of course, the clock time limits. As preparation for the following studies describe eq[18] in your own words. What does its left hand side mean? What does its right hand side mean? You might wish to include in your word description the phrases â€Å"difference between† and  "area under the curve of†¦ † or other equivalent phrases. Pay attention to the clock time limits. If you understand this expression enough to explain it in your own words you will have no trouble with the following activities. Calculating the area under a curve is easy with the software supplied. LoggerPro will compute the area under a region of a curve you select, i. e. , between two limits. You must first select the region by dragging with the mouse as was illustrated in Figure 12. Pick a region of the velocity versus clock time graph between two bumps (which is linear) and drag over the region to select it. Next choose Analyze Integrate. Your result might resemble Figure 14. Do your best to confirm eq[9]. Repeat in a similar fashion for the relationship between the velocity and acceleration. Graph produced by LoggerPro, copied to the clipboard and pasted directly into Microsoft Word. Figure 14. A velocity vs clock time graph showing an integration. The area under the curve for the time limits chosen is 0. 222 m/s/s. Other Features and Other Questions There are other features of the graphs whose interpretation involves interesting physics. For example, explain in your own words and with sketches why the features shown in Figures 15a and 15b appear on the velocity and acceleration graphs. Why does the acceleration go from zero to a maximum positive value then drop to zero again? Explain why both â€Å"positive† and â€Å"negative† bumps appear on the acceleration graphs. Does the magnitude of the velocity have the same value after, as before, a bump? What does this say about the kind of collision at the bump? L2-14 Linear Motion L2 Figure 15. Interesting structures in the velocity and acceleration graphs. Exercise 4. Energy The objective of this exercise is to examine as many aspects of energy as time permits. Viewing the Energy Graphs To view the energy graphs follow the procedure of Option 1 of Exercise 1. Your total energy graph may or may not resemble Figure 16. Observations and Questions Explain in your own words the characteristics of the kinetic energy graph. That is, answer or otherwise account for the following (interrelated) questions: Conservation of Energy Questions: ? Is mechanical energy conserved in this experiment? If not, why not? ? Why are the potential energy and kinetic energy graphs curves and not straight lines? Energy Loss Of course, friction is present here and does account (at least partially) for the decline in total energy. Explain how you might calculate the total energy lost per second? Other Questions What might be another source of energy loss besides friction? How would you go about quantifying this loss? ? ? ? What accounts for the â€Å"dips† in the kinetic energy graph? The dips in the kinetic energy graph show that the kinetic energy is zero for a brief instant. How is it possible for the glider to lose all of its kinetic energy and then regain it again? Describe all instances of work being done and by what agent. ? ? Graph produced by LoggerPro, copied to the clipboard and pasted directly into Microsoft Word. Figure 16. A total energy vs clock time graph. The energy is nearly a constant here at just under 0. 05 J. It would still be useful to find the energy lost per second from a linefit. L2-15 L2 Linear Motion Physics Demonstrations on LaserDisc There are many physics demonstrations on laserdisc dealing with motion in one dimension. Here are just a few of them: from Chapter 2 Linear Kinematics Demo 01-08 Constant Velocity Demo 01-11 Constant Acceleration from Chapter 3 Linear Dynamics Demo 03-01 Air Track Friction Stuart Quick 2003 End Notes for Linear Motion 1 2 If you can’t follow the calculus here go directly to the main equations [10] and [11]. By point mass is meant an object whose internal structure is to be neglected. Or in other words, a point mass is an idealized object of mass m of infinitely small size. Some of the work done on an object of finite size could conceivably go into increasing the object’s internal energy, something we wish to avoid here. In this guidesheet the word object will mean point mass. 3 If you wish to bypass the calculus go directly to the main results, eqs [15] and [16]. 4 5 This change is effected by putting a = dv and dr = dr dt. This is similar to how a bat sees in the dark using its own kind of ultrasound. It is also how a Polaroid autofocus camera determines the distance to an object to focus properly. Similar principles apply to ultrasound devices used in medicine and to various range-finding devices. dt dt L2-16

PRICE Surname Meaning and Family History

PRICE Surname Meaning and Family History Price is a patronymic surname derived from the Welsh ap Rhys, meaning son of Rhys. The given name Rhys means enthusiasm in Welsh. Price is the 84th most popular surname in the United States. Price is also popular in England, coming in as the 47th most common surname. Surname Origin:  Welsh Alternate Surname Spellings:  PRYCE, PRIS, PRYS, PREECE, PREES, PRICE, PREIS, PREUSS   Famous People with the PRICESurname Leontyne Price  - African-American professional soprano opera singerVincent Price  -  American actorBruce Price  - architect of many of the Canadian Pacific Railways Chà ¢teau-type stations and hotelsCarey Price -  Canadian hockey goaltender for the NHL Montreal CanadiensRichard Price - Welsh philosopherWilliam Price - 19th-century Welsh physician and eccentricFlorence Beatrice Price (born Smith)  -  award-winning African-American  pianist and composer Where is the PRICE Surname Most Common? According to surname distribution from  Forebears, Price is the 1,357th most common surname in the world- found most prevalently in the United States, but most common in Wales based on percentage of the population bearing the name. The Price surname ranks as the 19th most common last name in Wales, 71st most common in England and 82nd most common in the United States. In  1881 the Price surname was most common in southern Wales, especially in Glamorganshire, Brecknockshire, Radnorshire and Monmouthshire. Surname maps from  WorldNames PublicProfiler  also show the Price surname as especially common in Wales, as well as in the West Midlands region of England. Within the United States, Price is most common in the state of North Carolina, followed by South Carolina and West Virginia.   Genealogy Resources for the Surname PRICE 100 Most Common U.S. Surnames Their MeaningsSmith, Johnson, Williams, Jones, Brown... Are you one of the millions of Americans sporting one of these top 100 common last names from the 2000 census? Price, Priest, Pryce Surname DNA ProjectThis DNA project is connecting individuals with the Price surname and Welsh derivatives such as  Breece, Breeze, Brice, Bryce, Preece, Preecs, Prees, Priest, Pris, Prys, Reece, Rees, Reese, Rhys, Rice and the German variants Preis and Preuss, who are interested in using both Y-DNA and mtDNA testing to help discover common Price or Pryce ancestors. Price Family Crest - Its Not What You ThinkContrary to what you may hear, there is no such thing as a Price family crest or coat of arms for the Price surname.  Coats of arms are granted to individuals, not families, and may rightfully be used only by the uninterrupted male line descendants of the person to whom the coat of arms was originally granted. Price Family Genealogy ForumThis free message board is focused on descendants of Price ancestors around the world. Search or browse the archives for your Price ancestors, or join the group and post your own Price family query. FamilySearch - PRICE GenealogyExplore over 5.4  million results from digitized  historical records and lineage-linked family trees related to the Price surname on this free website hosted by the Church of Jesus Christ of Latter-day Saints. DistantCousin.com - PRICE Genealogy Family HistoryExplore free databases and genealogy links for the last name Price. GeneaNet - Price  RecordsGeneaNet includes archival records, family trees, and other resources for individuals with the Price  surname, with a concentration on records and families from France and other European countries. The Price  Genealogy and Family Tree PageBrowse genealogy records and links to genealogical and historical records for individuals with the Price surname from the website of Genealogy Today.- References: Surname Meanings Origins Cottle, Basil.  Penguin Dictionary of Surnames. Baltimore, MD: Penguin Books, 1967. Dorward, David.  Scottish Surnames. Collins Celtic (Pocket edition), 1998. Fucilla, Joseph.  Our Italian Surnames. Genealogical Publishing Company, 2003. Hanks, Patrick and Flavia Hodges.  A Dictionary of Surnames. Oxford University Press, 1989. Hanks, Patrick.  Dictionary of American Family Names. Oxford University Press, 2003. Reaney, P.H.  A Dictionary of English Surnames. Oxford University Press, 1997. Smith, Elsdon C.  American Surnames. Genealogical Publishing Company, 1997. Back toGlossary of Surname Meanings Origins

Criminal Justice - Homicide Studies Research Paper

Criminal Justice - Homicide Studies - Research Paper Example Report on the Ethics Committee, 2010 The Ethics Committee reports regularly to the American Psychological Association. In its report of 2010 the committee has address the topics pertaining to the ethical issues such as psychologist consulting to reality TV programs, psychotherapy, issues related to psychologist, giving psychological treatment over the internet, etc. In 2010 the Ethics Committee responded to majority of the requests received by the office and attended 46 workshops and discussions on national and international level throughout the year. The responsibilities of Ethics Committee includes to consider the individual cases, cases of the state licensing board or court and finally those which result from committee’s own initiative after getting information from the public. The Ethics Committee starts its working when it receives an inquiry letter from an individual. The show case process starts with a notice from the state licensure board. Then the preliminary investig ations are made to decide whether the case should be closed or it should proceed to the level of formal case. These investigations provide detail information about complain. Formal cases are opened if the responded proved to be charged for ethical violation. The cases pertaining to ethics which meet the threshold criteria are then referred for resolution. The sanctions described in Rules and Procedures (APA, Ethics Committee, 2002) includes that the individuals should be terminated from the APA membership or they should be reprimanded or censured. In the cases reviewed by the committee in 2010 no reprimands were made, there were two cases of censure and five cases of loss of membership. Crime and Delinquency The American population is exposed to pictures of crime and delinquency through all the digital devices and social media which results in fear and affect the attitude of the people and their voting habits. Politicians are using crime and delinquency in their policy agendas to at tract people to vote for them. The relationship between crime, delinquency and political science is determined by deterrence theory, conflict theory, labeling theory and radical theory. All of these are related to the main topic because they are considered important by the political science, crime and delinquency scholars and the theories include the analysis of government and political institutions. The theories are useful in explaining the government and political processes about the criminal acts. After selecting the theories further research articles were obtained from J-store sociological database on the basis of contemporary theoretical trends and past development of the tactic. The results showed that the societal fears gives rise to criminal acts and ultimately ends on criminal punishment. Deterrence theory suggests that the criminals should be punished publically so that it discourages the public to involve in such activities. Conflict theory suggests that criminal acts hav e their roots in the instability between political and social groups. According to the labeling theorist the criminals should be labeled negatively but this negative label can encourage the criminals to act in the same way in future as well. Historical records have shown that the labeling

Blood Donation Marketing analysis Research Paper

Blood Donation Marketing analysis - Research Paper Example The collected blood will be supplied to the military camps, churches, community organizations etc for emergency purposes ( American Red Cross, 2010).The guidelines, benefits of the blood donation camp are available for free through social media networks like Facebook, YouTube and Twitter (Donate Blood, 2013d). Weakness Recruitment of first time blood donors require extensive identification, education and motivation. Training, educating and motivation these first time blood donors consumes a lot of time (Red Cross, 2010). The trainers have to maintain a record of the first time blood donors since the repeat donors are already provided with an identity card by the blood organizer camp. Apart from time consumption, the blood organizers have to deal with the pre donation anxiety and nervousness of the first time blood donors. Opportunity The benefits about blood donation are being taught to the college children, this has eased the task of the blood donation camps to communicate the benefits of blood donation. Technological development has made it easier for the blood donors to schedule their appointments online (Donate Blood, 2013e).... †¢To develop an integrated marketing communication strategy which motivates current, non and lapsed donors in the target market to increase their blood donations in 2013-14. †¢To improve and increase blood donation accessibility for the 18-24 year-old age group in 2013-14. Issue Analysis In Australia, marketing effort is aimed at attracting and maintaining sufficient numbers of regular, volunteer blood donors in the under-represented age group of 18 to 24 year-olds. It is essential that the Australian Red Cross Blood Service ensures are reasonable and safe blood supply throughout the year. Each week, at least 27,000, blood donations, are required to assist people with serious blood illnesses (e.g., cancer, blood diseases), surgical patients (e.g., open heart surgery, burns), kidney disease patients, pregnant women and traumatic accident patients (Australian Red Cross Blood Service, 2013). Only a relatively small percentage of the eligible population within the 18-24 year-ol d age group donates blood on a regular basis. Furthermore, eligible donors often lapse in their blood donating behaviour after their blood donation. Marketing Strategy Arranging for a blood donation campaign is a challenging task and requires intensive market study, planning and psychological analysis of the blood donors. An effective marketing strategy needs to be developed to ensure the smooth functioning of the blood donation campaign. Marketing Objective To encourage blood donation among individuals aged between 18 to 24 years old from the period 01 July 2013 to 30 June 2014. Budget Allocation The allocated budget for the blood donation campaign would be AUD20 million which would be required to cover the research process, media, medical equipments, advertising

Post-Traumatic Stress Disorder in Iraq Veterans Essay Example for Free

Post-Traumatic Stress Disorder in Iraq Veterans Essay Post-traumatic Stress Disorder is a condition characterized by excessive fear, helplessness, or horror resulting from an experience of excessive trauma. Its symptoms include persistent relapse of the traumatic experience, avoidance of stimuli related to the trauma, lack of general responsiveness, and lingering symptoms of heightened autonomic arousal (Long, 1995). The State of Post-Traumatic Stress Disorder  All these symptoms must manifest themselves for over a month, and the condition must bring about a clinically significant pain or impairment in social, occupational, or other important aspects of functioning (Long, 1995). According to a study conducted by the Pentagon, almost one out of ten American soldiers who went on a tour of duty in Iraq suffered post-traumatic stress disorders (PTSD) after seeing a dead comrade or taking part in combat. The findings of the study could trigger a budget battle in Congress over the health care of veterans (Strong, 2006). The survey, which involved 222,620 Army and Marine soldiers coming home from Iraq, 16,318 from Afghanistan, and 64,967 from other places, revealed that over 1/3 of American soldiers received psychological counseling immediately after coming home from Iraq (Strong, 2006). Published in the Journal of the American Medical Association, the report revealed that nineteen percent of the returnees satisfied the â€Å"risk criteria for a mental health concern† of the military which is higher than the 11. 3% and 8. 5% of those who returned from Afghanistan and other deployments, respectively (Strong, 2006). According to Dr. Charles Hoge, who co-authored the study and serving as a colonel at the Walter Reed Army Institute of Research, said that the findings of the research did not come as a surprise to them since the military is implementing a new mental health evaluation program for returning soldiers which encourages them to seek medical help early to avoid any serious complications in the future (Strong, 2006). Post-traumatic stress disorder was likewise experienced by soldiers who were deployed to Vietnam. Administered in 1990, the National Vietnam Veterans Readjustment Study conducted by The Research Triangle Institute contracted by the Veterans Affairs Administration, the research revealed that 31 percent of the soldiers deployed to Vietnam which translates to 1 million troops experienced PTSD after their return (Satel, 2004). Psychiatric reports attached to the study showed that 12 to 15 out of every 1000 soldiers succumbed to psychiatric disorder. If the 1990 research is accurate, the number of Vietnam War veterans who suffered from PTSD increased vastly in post-war era (Satel, 2004). In the Pentagon study, 80 percent of those who was diagnosed with PTSD said that they saw their comrades getting killed or wounded or took part in combat and shot their weapon. Among those who did not experience PTSD, half participated in combat and experienced violence (Strong, 2006). The Effects of Post-Traumatic Stress Disorder According to Judith Broder (2008), psychiatrist and founder of the Soldiers Project, a volunteer organization geared towards treating war veterans for free, the excessive trauma as well as the fear of getting almost killed are common signs of post-traumatic stress disorder. It is quite understandable as soldiers are sent to unfamiliar territory and will always find themselves in a dangerous situation and tends to be cautious all the time. For most soldiers who are deployed in Iraq making the transition to a peaceful life after months or years of being in action can be challenging (Terzyan, 2008). The reason for the growth in post-traumatic stress disorder is not only because troops have now become more aware of the condition but also due to the extended separation from their families and secured conditions. Likewise, troops are prone to PTSD because the nature of their job demands their being exposed to life-threatening and stressful conditions (Terzyan, 2008). Treating Post-Traumatic Stress Disorder Contrary to what many people think, treating post-traumatic stress disorder in war veterans can be quite complicated. There is evidence that proves that taking any kind of medication is not as effective in war veterans as it is in ordinary citizens, and there is minimal research on antidepressants for combat troops (Spollen Labbate, 2008). A small study used fluoxetine in treating post-traumatic stress disorder in war veterans. The findings showed minimal improvements in veterans than civilians. A similar study this time using sertraline yielded the same result (Spollen Labbate, 2008). Psychological and social intervention may be the first choice when it comes to veterans with PTSD. In some instances, they are more valuable interventions than medication. Building trust between patient and provider is the initial step in the conduction of treatment. However, establishing such connection can be difficult with patients who has suffered traumatic stress (Reeves, 2007). Treating Iraq veterans with post-traumatic stress disorder poses a real challenge to primary care providers. For many patients, an early alternative would be to visit a Veterans Affair (VA) medical facility. The United States Department of Veteran Affairs has trained physicians in the field of PTSD and Iraqi veterans coming home are qualified for treatment (Reeves, 2007). Conclusion Post-traumatic Stress Disorder (PTSD) is a condition characterized by excessive fear, helplessness, or horror resulting from an experience of excessive trauma. Its symptoms include persistent relapse of the traumatic experience, avoidance of stimuli related to the trauma, lack of general responsiveness, and lingering symptoms of heightened autonomic arousal. According to a study conducted by the Pentagon, almost one out of ten American soldiers who went on a tour of duty in Iraq suffered post-traumatic stress disorders (PTSD) after seeing a dead comrade or taking part in combat. The findings of the study could trigger a budget battle in Congress over the health care of veterans. The reason for the growth in post-traumatic stress disorder is not only because troops have now become more aware of the condition but also due to the extended separation from their families and secured conditions. Likewise, troops are prone to PTSD because the nature of their job demands their being exposed to life-threatening and stressful conditions. Contrary to what many people think, treating post-traumatic stress disorder in war veterans can be quite complicated. There is evidence that proves that taking any kind of medication is not as effective in war veterans as it is in ordinary citizens, and there is minimal research on antidepressants for combat troops. Psychological and social intervention may be the first choice when it comes to veterans with PTSD. In some instances, they are more valuable interventions than medication. Building trust between patient and provider is the initial step in the conduction of treatment. However, establishing such connection can be difficult with patients who has suffered traumatic stress.

Alzheimers The Unsolved Mystery Essay -- essays research papers fc

Alzheimer's: The Unsolved Mystery   Ã‚  Ã‚  Ã‚  Ã‚  Absentmindedness, with questions having to be repeated, trouble following conversations, or remembering people's names, sound familiar? These are classic early stage symptoms of Alzheimer's.   Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  Alzheimer's is a type of dementia in which parts of the brain stop working, causing memory loss, and instability in judgement, reasoning and emotions. Dementia, such as Alzheimer's is usually more frequent in elderly people. Approximately 15 percent of people who are over 65 will develop some form of dementia; by the age of 85 that percentage increases by at least 35 percent. Alzheimer's is the most common dementia, nearly four million Americans suffer from it.   Ã‚  Ã‚  Ã‚  Ã‚  Alzheimer's is a very complex disease. So complex that very little has been discovered about it but that is rapidly changing. Findings from epidemiology, genetics, molecular and cell biology are fitting together in the Alzheimer's puzzle, helping researchers to identify some of the mechanisms that underlie it. Alzheimer's starts because the normal processing of certain proteins goes terribly wrong. This causes brain cells and the spaces between them to be cluttered with pieces of toxic protein. Closer investigating with microscopes has revealed a loss of nerve cells in certain regions of the brain. Some of these dying nerve cells communicate using the neurotransmitter acetylcholine, these compounds eventually break down by an enzyme called acetylcholinesterase. Also responsible for Alzheimer's are clusters of proteins in the brain which come in two forms: those found inside the nerve cells and those found in between the cells.   Ã‚  Ã‚  Ã‚  Ã‚   The clusters inside the cells look like pairs of threads wound around each other in a helix. The tangles consist of a protein called tau. Tau binds to another protein called tubulin. Tubulin then forms structures called microtubules which run through cells, giving support and shape. Also the microtubules provide pathways for nutrients and other molecules to travel through.   Ã‚  Ã‚  Ã‚  Ã‚  The main problem is that researchers can't quite figure out how Alzheimer's is started. Some the leads are its inherited genetically, is caused by major head injury, poor earl... ... on this amazingly complex disease. The BAPP theory only accounts for five percent of all Alzheimer's cases. Some may believe that this is a small step in uncovering the mystery of Alzheimer's but I believe it will be a huge one after its throughly examined. The BAPP discovery should help open the door for Alzheimer's and reveal more about how the disease functions and what exactly causes it. For those people who are infected with the disease they can only sit in agony and hope that a more powerful insight is made for the sake of future generations. It is believed that by 2025 more than 22 million people world wide will be infected with Alzheimer's and as the average life span lengthens the percentage only gets steeper.   Ã‚  Ã‚  Ã‚  Ã‚  Alzheimer's is the worst kind of disease. It not only infects the being with which it is in but it also affects the people who know and love that person. For mankind's sake hopefully more work will be put into establishing a cure for this awful dementia. Bibliography:   Ã‚  Ã‚  Ã‚  Ã‚  Author: Peter H. ST. George-Hyslop , Scientific American, December 2000   Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚   Alzheimers The Unsolved Mystery Essay -- essays research papers fc Alzheimer's: The Unsolved Mystery   Ã‚  Ã‚  Ã‚  Ã‚  Absentmindedness, with questions having to be repeated, trouble following conversations, or remembering people's names, sound familiar? These are classic early stage symptoms of Alzheimer's.   Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  Alzheimer's is a type of dementia in which parts of the brain stop working, causing memory loss, and instability in judgement, reasoning and emotions. Dementia, such as Alzheimer's is usually more frequent in elderly people. Approximately 15 percent of people who are over 65 will develop some form of dementia; by the age of 85 that percentage increases by at least 35 percent. Alzheimer's is the most common dementia, nearly four million Americans suffer from it.   Ã‚  Ã‚  Ã‚  Ã‚  Alzheimer's is a very complex disease. So complex that very little has been discovered about it but that is rapidly changing. Findings from epidemiology, genetics, molecular and cell biology are fitting together in the Alzheimer's puzzle, helping researchers to identify some of the mechanisms that underlie it. Alzheimer's starts because the normal processing of certain proteins goes terribly wrong. This causes brain cells and the spaces between them to be cluttered with pieces of toxic protein. Closer investigating with microscopes has revealed a loss of nerve cells in certain regions of the brain. Some of these dying nerve cells communicate using the neurotransmitter acetylcholine, these compounds eventually break down by an enzyme called acetylcholinesterase. Also responsible for Alzheimer's are clusters of proteins in the brain which come in two forms: those found inside the nerve cells and those found in between the cells.   Ã‚  Ã‚  Ã‚  Ã‚   The clusters inside the cells look like pairs of threads wound around each other in a helix. The tangles consist of a protein called tau. Tau binds to another protein called tubulin. Tubulin then forms structures called microtubules which run through cells, giving support and shape. Also the microtubules provide pathways for nutrients and other molecules to travel through.   Ã‚  Ã‚  Ã‚  Ã‚  The main problem is that researchers can't quite figure out how Alzheimer's is started. Some the leads are its inherited genetically, is caused by major head injury, poor earl... ... on this amazingly complex disease. The BAPP theory only accounts for five percent of all Alzheimer's cases. Some may believe that this is a small step in uncovering the mystery of Alzheimer's but I believe it will be a huge one after its throughly examined. The BAPP discovery should help open the door for Alzheimer's and reveal more about how the disease functions and what exactly causes it. For those people who are infected with the disease they can only sit in agony and hope that a more powerful insight is made for the sake of future generations. It is believed that by 2025 more than 22 million people world wide will be infected with Alzheimer's and as the average life span lengthens the percentage only gets steeper.   Ã‚  Ã‚  Ã‚  Ã‚  Alzheimer's is the worst kind of disease. It not only infects the being with which it is in but it also affects the people who know and love that person. For mankind's sake hopefully more work will be put into establishing a cure for this awful dementia. Bibliography:   Ã‚  Ã‚  Ã‚  Ã‚  Author: Peter H. ST. George-Hyslop , Scientific American, December 2000   Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  

Externalities of Smoking

In the paper I’m going to discuss the externalities of second-hand smoke. Externalities refer to all costs or benefits of a market activity borne by a third party. It’s also the difference between the social and private costs (benefits) of a market activity. When economic agents are not directly involved, negative externalities can exist, such as pollution. Second-hand smoke is a health hazard at any level (Essentials Of economics, Bradley R. Schiller). It’s to be said that smoking bans are the only way to protect nonsmokers.Although many states and hundreds of cities have passed smoke-free laws, more than 126 million Americans ages 3 and older continue to be exposed to secondhand smoke. Nearly 50,000 nonsmokers die from the secondhand smoke each year. Nonsmokers exposed to secondhand smoke at home or work increase their risk of heart disease and cancer. Brief exposure to smoke, damages cells, beginning a process that can lead to cancer, and increase the risk of blood clots (USA today: June 28, 2006).Secondhand smoke kills 46,000 adult nonsmokers from heart disease, 3,000 nonsmokers from lung cancer, and 430 newborns from sudden infant death syndrome. In children it causes 790,000 ear infections, 200,000 episodes of asthma, at least 24,000 low birth weight or preterm deliveries. When non-smokers are exposed to secondhand smoke it’s called involuntary smoking or passive smoking. Regardless if you’re smoking or not, if you’re around someone who is smoking you’re taking in nicotine and other toxic chemicals just like smokers do.The workplace is a major source of secondhand smoke exposure for adults (USA today: June 28, 2006). Secondhand smoke meets the standard to be classified as a potential cancer-causing agent by the Occupational Safety and Health Administration (cancer. org). Separating smokers from non-smokers, cleaning the air, and ventilating the building cannot prevent exposure if people still smoke inside t he building. Most people can be exposed in public places such as restaurants, shopping centers, public transportation, schools, and daycare centers.Some businesses seem to be afraid to ban smoking, but there is no proof that going smoke-free is bad for business. Public places where children go are a special area of concern (cancer. org). Making your home smoke free is healthier for your family. Secondhand smoke imposes significant costs on nonsmokers and society, according to a recent society of Actuaries study that concluded the annual cost of excess medical care, mortality and morbidity from secondhand smoke exposure in the U. S is approximately $ 10 billion(18 Aug 2005).The study also found that medicals costs for caring for people exposed to secondhand smoke have reached more than $2. 5 billion (medicalnewstoday. com). All the money you spend on cigarettes is just going to the company that makes them. So you’re giving this company all this money to just smoke a cigarette. On average most people pay about close to seven dollars for a box of cigarettes. Not only is this harmful to you, but its as harmful to the people around you. When you smoke in front of someone their inhaling all the chemicals that are carried In that one cigarette.So in conclusion this affects the economy so much, because people who don’t even smoke have to pay for all types of medicals bills. Just from getting secondhand smoke from others. I myself don’t think they should banned smoking. But there should be sections in public places which are meant for smokers. Some people can’t just stop smoking no matter what they do. So at the same time we have to respect their needs. And their needs are nicotine. Sources ?Cancer. org ?Medicalnewstoday. com ?USA today: June 28, 2006 ?Essentials of economics (Bradley R. Schiller)

Méliès’s Trip to the Moon Essay

The film opens with a gathering of academics in a lecture hall. They have robes, beards and pointed hats. They are standing at first in ranks in the room, five more men join them and are given telescopes by female servants. The leader enters and assumes a position at a blackboard on the left where he draws an image of the Earth and the Moon and a bullet-shaped craft landing on the Moon. They all being discussing or arguing about the project. The technique used for acting is based on what one might see acted out in the theater with no modern cinematography such as close-ups or zooms are used to focus the attention on a particular character. All the characters appear onstage and if there is any focus on a certain action is done through theatrical technique such as the females marching out and handing out telescopes and leaving. When the main character, seeming like a professor comes in the group sort of comes to attention and stand still at first while the professor speaks and draws on the board. One’s attention’s shifts to the group again as they discuss and argue with over-large gesticulations in this silent film without written inter-titles. It is a silent stage drama recorded on film, else it would be mime theatre. The film’s scene changes almost like a shift of scene in the theatre. There is a very fake-looking space capsule that is being worked on and some of the astronauts try out the interior. There is a moment when someone falls into a shallow barrel. Possibly, this was meant to be a comic touch which would be at home later in vaudeville. There is no camera movement. It is as if one had a good seat at the theatre and watching a series of tableaux vivantes. The film owes much more to the stage and picture books than to any already-developed film technique. The subsequent boarding of the space-bullet on the left with the cannon on the right looks especially fake and hand-drawn. There is little aim at a believable set and much over-acting: doffing their hats and so on to an imaginary group of spectators, actually us who are watching the living theater more than a film by today’s standards. After the firing of the cannon, there occurs the use of something like special effects where the Man in the Moon, framed by clouds comes closer to the viewer and has human like expressions which show the space vehicle hitting him in the eye. It is a real human looking like he has whipped cream on his face.

Aluminum or Aluminium Alloys - List

Aluminum or Aluminium Alloys - List An aluminum alloy is a composition consisting mainly of aluminum to which other elements have been added. The alloy is made by mixing together the elements when aluminum is molten (liquid), which cools to form a homogeneous solid solution. The other elements may make up as much as 15 percent of the alloy by mass. Added elements include iron, copper, magnesium, silicon, and zinc. The addition of elements to the aluminum gives the alloy improved strength, workability, corrosion resistance, electrical conductivity, and/or density, compared with the pure metallic element. Aluminum alloys tend to be lightweight and corrosion resistant. List of Aluminum Alloys This is a list of some important aluminum or aluminium alloys. AA-8000: used for building wire per the National Electrical CodeAlclad: aluminum sheet made by bonding high-purity aluminum to a high strength core materialAl-Li (lithium, sometimes mercury)Alnico (aluminum, nickel, copper)Birmabright (aluminum, magnesium)Duralumin (copper, aluminum)Hindalium (aluminum, magnesium, manganese, silicon)Magnalium (5% magnesium)Magnox (magnesium oxide, aluminum)Nambe (aluminum plus seven other unspecified metals)Silumin (aluminum, silicon)Titanal (aluminum, zinc, magnesium, copper, zirconium)Zamak (zinc, aluminum, magnesium, copper)Aluminum forms other complex alloys with magnesium, manganese, and platinum Identifying Aluminum Alloys Alloys have common names, but they may be identified using a four-digit number. The first digit of the number identifies the class or series of alloy. 1xxx - Commercially pure aluminum also has a four-digit numerical identifier. Series 1xxx alloys are made of 99 percent or higher purity aluminum. 2xxx - The principal alloying element in the 2xxx series is copper. Heat treating these alloys improves their strength. These alloys are strong and tough, but not as corrosion resistant as other aluminum alloys, so they are usually painted or coated for use. The most common aircraft alloy is 2024. Alloy 2024-T351 is among the hardest of the aluminum alloys. 3xxx - The main alloying element in this series is manganese, usually with a smaller amount of magnesium. The most popular alloy from this series is 3003, which is workable and moderately strong. 3003 is used to make cooking utensils. Alloy 3004 is one of the alloys used to make aluminum cans for beverages. 4xxx - Silicon is added to aluminum to make 4xxx alloys. This lowers the melting point of the metal without making it brittle. This series is used to make welding wire. Alloy 4043 is used to make filler alloys for welding cars and structural elements. 5xxx - The principal alloying element in the 5xxx series is magnesium. These alloys are strong, weldable, and resist marine corrosion. The 5xxx alloys are used to make pressure vessels and storage tanks and for various marine applications. Alloy 5182 is used to make the lid of aluminum beverage cans. So, aluminum cans actually consist of at least two alloys! 6xxx - Silicon and magnesium are present in 6xxx alloys. The elements combine to form magnesium silicide. These alloys are formable, weldable, and heat treatable. They have good corrosion resistance and moderate strength. The most common alloy in this series is 6061, which is used to make truck and boat frames. Extrusion products from the 6xxx series are used in architecture and to make the iPhone 6. 7xxx - Zinc is the principal alloying element in the series starting with the number 7. The resulting alloy is heat-treatable and very strong. Important alloys are 7050 and 7075, both used to construct aircraft. 8xxx s include 8500, 8510, and 8520. 9xxx - Presently, the series starting with the number 9 is unused. What Is the Strongest Aluminum Alloy? Manganese added to aluminum increases its strength and yields an alloy with excellent workability and corrosion resistance. The highest strength alloy in the non-heat-treatable grade is alloy 5052. Aluminum Alloy Classification In general, the two broad categories of aluminum alloys are wrought alloys and casting alloys. Both of these groups are subdivided into heat-treatable and non-heat-treatable types. Around 85% of aluminum is used in wrought alloys. Cast alloys are relatively inexpensive to produce because of their low melting point, but they tend to have lower tensile strengths than their wrought counterparts. Sources Davis, J.R. (2001). Aluminum and Aluminum Alloys. Alloying: Understanding the Basics. pp. 351–416.Degarmo, E. Paul; Black, J T.; Kohser, Ronald A. (2003). Materials and Processes in Manufacturing (9th ed.). Wiley. p. 133. ISBN 0-471-65653-4.Kaufman, John Gilbert (2000). Applications for Aluminium Alloys and Tempers. Introduction to aluminum alloys and tempers. ASM International. pp. 93–94. ISBN 978-0-87170-689-8.

How to Prepare for the CCNA Exam

How to Prepare for the CCNA Exam Cited consistently by recruiters and hiring managers as one of the most sought-after certifications in the IT industry, the CCNA is one of the most valuable certifications you can have on your resume. Moreover, it’s required for most higher-level Cisco certifications like the CCNP and CCDP (and, by extension, the CCIE). Earning the CCNA demonstrates that you have the ability to configure and support a range of Cisco network devices, along with a strong general knowledge of networking, network security, and wireless networking- all of which are required to support the modern enterprise network. But before you can become a CCNA, you need to pass Cisco exam 640-802 (or, alternately, exams 640-822 and 640-816 together), which is required in order to earn the certification. The CCNA exam is challenging, and passing it definitely requires a lot of work and effort. But with the right focus and preparation, passing the CCNA exam is an achievable goal. To get you started, here are some tips to use in preparing for your CCNA examination. Set a Course of Study The first order of business should be to set the direction for your individual study. Cisco offers a syllabus for the CCNA certification, with a list of topics that are covered. Review this list, print it out and post it, and use it as your guide in crafting your personal course of study. Remember- if its not on the syllabus, its not on the exam, so limit your studies to the topics that Cisco highlights. Identify Your Weaknesses A good next step is to identify those areas where you’re weakest (hint: try a practice exam to help identify those areas)  and make them the focus of your study and practice. Highlight those areas, and set a specific goal towards gaining a good understanding of each. Don’t necessarily neglect your areas of strength completely (you don’t want to forget what you’ve already learned!), but by turning your weaknesses into strengths you can dramatically increase your chances of passing the CCNA exam. Make Time for Study The CCNA isn’t an easy exam to pass, and it covers a lot of ground. And, like any technical discipline, if you don’t work at it on a consistent basis, your knowledge and skills will fade. Set aside a consistent, regular time for study, and make sure that you keep to it. Granted, it can be hard to keep this time blocked out, especially with all of the daily responsibilities and distractions that we all deal with. But the key to passing the CCNA is frequent and consistent study and practice, so it’s critical that you set this time aside, limit your distractions, and stick to the task at hand. Focus on the Details It’s not enough to know the theory behind the concepts presented in the CCNA curriculum. To successfully pass the CCNA exam, you need to how to complete tasks and understand how things get done in the world of Cisco. That’s an important point  because general networking concepts and the way Cisco does things are not always the same- so it’s important to understand the details and specific methods and procedures for implementing different networking technologies, within the Cisco environment. Get Access to Gear This point cant be stressed enough. A big portion of the CCNA exam consists of completing tasks on simulated routers and switches, just as you’ll do them in real life. That’s why it’s critical that you get practice time (preferably a lot of it) on Cisco equipment  so that you can implement what you study within the actual Cisco IOS environment. You can buy or rent pre-configured sets of actual Cisco routers and switches that contain all of the equipment you’ll need to practice for the exam, and these sets are not as expensive as you might think. Also, there are also some excellent simulators out there, that let you configure virtual routers and switches from your personal computer. Take a look at Packet Tracer, which is an excellent tool available from the Cisco Academy, and Graphical Network Simulator 3 (GNS3), which is a free open-source tool that provides a simulated Cisco IOS environment (you can also use it to simulate the Juniper JunOS platform as well). Practice All of the Topics on the Exam, Firsthand Once your practice environment is up and running, make sure you take full advantage of it and practice implementing every protocol and configuration possible, so that you can see how everything works on the actual gear. Remember, things in real life don’t always work the same as they do on paper, and just because a book or guide tells you that a given configuration will produce a given result, nothing beats seeing it for yourself, especially on those (hopefully rare) occasions when the books get it wrong. The key to passing the CCNA exam is preparation  and lots of it. To pass the test, you’ll need to understand networking theory, facts, and practice, and be able to readily utilize the Cisco IOS interface, including specific commands and syntax. But, if you take the time to truly learn the material and get to know your way around Cisco routers and switches beforehand, you should find the test relatively easy to pass.

The Changing Roles Of Women In The Mafia Essay Example | Topics and Well Written Essays - 3250 words

The Changing Roles Of Women In The Mafia - Essay Example The study will focus on analysing information from authorities that are known for their efforts and track-record in researching into the Sicilian Mafia and Organised crime groups. In doing this, the research will focus on contemporary research works and field works that have been done by conducting various primary studies and research work like interviews and other things meant to inquire into the way research is done into the Sicilian model of the mafia and its processes. The research will also seek to inquire into specialised sources and works of authors who have in-depth experience and knowledge in studying women and the Mafia. This will include an insight into numerous works by persons who have spent the most part of the past 20 years studying and researching into the works of the Mafia and their evolutions over the period at hand. This report makes a conclusion that women in the Mafia were traditionally seen as the bedrock for the keeping together and transmission of the amoral familial traits of organized crime families and clans in Sicily. However, the past 20 years has seen a lot of changes and modifications in the way things are done in the Mafia and in societies. This include the fact that the Mafioso is more interested in cashing in on the opportunity to make money through smuggling and owning businesses in order to participate in money laundering. This is opposed to the old system where the Mafia took part in violent activities and violent crimes and offences in order to raise money and remain rich.