Projectile Motion.docx

STAGE 2 PHYSICSRonAim:To determine how the different launch angles affect the range of a ball where the launch height is the same as the landing height.Hypothesis: usin=u(y), ucos=u(x) with the same initial speed, u(y) is increasing as increases. Oppositely u(x) is decreasing as increases.The range of projectile is the maximum when the launch angle is 45 and the range is decreasing as the launch angle increases or decreases.Apparatus:l Projectile launcherl Launch balll Clampl Meter rulel Lightgatel Date loggerVariables:l Independent variable: launch anglel Dependent variable: range of projectilel Controlled variable: the same apparatus, no wind, or other force effectsProcedure1. After reading the rest of the procedure, describe and explain the safety considerations for this investigation.2. Set up the apparatus as shown.3. Record the diameter of the launch ball. When the ball is fired the data logger will measure the time for this ball to pass through the light beam, the initial speed of the ball can be calculated by dividing the ball diameter by the this time.4. Prepare a target consisting of a magazine and carbon paper, ensuring that the landing height is the same as the launch height.5. Set the elevation to 45, fire several shots and record the range and launch angle.6. Repeat for angles 15, 25, 35, 55, 65, 75.Results:Angle()Range(m)Time (*10-3 s)Launch speed (m/s)150.912 1.063 1.025 3.40 3.62 3.54 Average1.000 3.52 5.10 1.565 3.89 251.643 3.52 1.885 3.48 Average1.698 3.63 4.94 2.104 3.53 352.063 3.60 2.011 3.66 Average2.059 3.60 4.99 2.195 3.66 452.181 3.67 2.215 3.50 Average2.197 3.61 4.97 2.153 3.57 552.005 3.69 2.123 3.33 Average2.094 3.53 5.08 1.864 2.96 651.795 3.52 1.743 3.74 Average1.801 3.41 5.27 1.232 3.54 751.243 3.56 1.145 3.43 Average1.207 3.51 5.11 Analysis: 1.2.3. usin=u(y), ucos=u(x)t(y)=0-usin-g*2t(x)=RangeucosRangeucos=2usingRange=2usin*ucosgRange=u2sin2gthe maximum value of sin2 is 1 when 2=90=45 when the range is the maximum.Evaluation:In this investigation, there are some random errors which can be reduced in the procedure. The horizontal direction of the launch device should be in the same way with the ruler which is used for measuring the range. It will be good to use a string to connect the end of the ruler and the launch device for making sure if the direction is straight before putting the ruler. When the angle of the launch device is being adjusted, the angle should be determined after the string totally stops. Its important that this experiment should be done without other force effects like wind (but the resistance of air cant be avoided) and the point where the ball land should be the same level with where the ball is launched.However, there are also some systematic errors in this experiment. The resistance between the ball and launch device slightly affects the launch speed and it can be reduced by using a more smooth launch device and ball. Secondly, each angle should be done for at least three times because its hard to determine the point where the ball land if just for once. Its better to cover a thin layer of sand on the place where the ball may land.The launch speed of each angle determined from the graph is a slightly less than the value calculated using the data logger. Its acceptable because there are some random or systematic errors in the data which is got from the experiment and therefore the value of the launch speed is affected to a certain extent.Conclusion:From this investigation, the effect of changing the launch angle when the l