Experiment 2: Squeeze Rocket™ ProjectilesIn this experiment, you will investigate how the launch angle of a projectile affects the distance it travels.MaterialsMasking TapeMirror SupportPrinter PaperProtractor4 Squeeze Rockets™ 1 Squeeze Rocket™ BulbStopwatchTape Measure*PencilProcedure1. Place the unused side of the printer paper face up on a flat work space and secure with a piece of masking tape. 2. Use a pencil to mark the spot in the middle of the printer paper. This is the where the rockets will be launched every trial. 3. Stabilize a protractor so that it stands up vertically by inserting the flat part of the protractor into the mirror support. Using a protractor, align the rocket to a 90° angle. In other words, it should be vertically directed upward. 4. Load a Squeeze Rocket™ onto the bulb.Note: The Squeeze Rocket™ is a trademarked product name. The “rocket” itself does not use a selfpropelled mechanism. After the Squeeze Rocket™ is launched, gravity is the only major force which acts upon the “rocket”. 5. Predict how far you believe the rocket will be propelled from its original position if you squeeze the bulb. Record your prediction in Table 5. 6. Squeeze the bulb (you will need to replicate the same pressure for each trial), and simultaneously start the stopwatch upon launch. Measure and record the total time the rocket is in the air. Repeat this step three more times, and average your results. Record all data in Table 5.Note: You may wish to include a partner for this step to work the stopwatch. 7. Calculate the launch velocity of the rocket using the kinematics equations. Record your calculation in Table 5.Hint: You can take the initial height as zero. The vertical velocity is zero at the peak of the flight, when the time is equal to t/2.) © 2014 eScience Labs, LLC.All Rights Reserved8. Choose three new angles from which to launch the rocket. Record the angles you select in Table 5. 9. Before launching the rocket, use the following equation to calculate the expected range using the launch velocity and the angle from which the rockets will be fired.R = v 2 sin(2θ) gRemember that you can use zero for any initial positions, and that the acceleration due to gravity, g, is - 9.8 m/s2. Record the expected ranges in Table 5.10. Next, align the rocket with the first angle choice and fire it with the same force you used initially. Squeeze the bulb and measure the distance traveled with the tape measure. Record the distance propelled for four, separate trials at this angle. Then, average the four trials and record in Table 5.Note: Try to record launches where the rocket travels in a parabola and does not stall or flutter at the top. 11. Repeat Step 9 - 10 for your remaining angles. Record all data in Table 5. 12. Record the percent error between your calculated and actual values in the last column. Percent error = observed value - expected value x 100 expected valueTable 5: Projectile Data for Rockets with Different Launch AnglesLaunch Velocity(m/s)Initial Angle Time (s)AverageTime (s)PredictedRange (m)ActualRange(m)AverageRange(m)Range%Error1.8 90 ° 1.23 1.645 0 0 0 090 ° 1.75 0 0 090 ° 1.92 0 0 090 ° 1.68 0 0 045° 1.38 1.645 3.23 1.75 2.09384.57 45°° 1.93 3.23 2.46 31.30 45° 1.74 3.23 2.21 46.1545° 1.53 3.23 1.95 65.6430° 1.48 1.573 2.842 1.332 1.4153 53.13© 2014 eScience Labs, LLC.All Rights Reserved30° 1.69 2.842 1.521 86.8630° 1.77 2.842 1.593 78.4030° 1.35 2.842 1.215 57.2325° 1.63 1.5100.25 1.24 1.14779.5925° 1.32 0.25 1.00 75.0025° 1.79 0.25 1.36 81.6225° 1.30 0.25 0.936 74.94Post-Lab Questions1. Which angle provides the greatest range? Which provides the least? Based on your results, which angle should give the greatest range for projectile motion?45 degrees gives the greatest range. 90 degrees gives the shortest range of zero2. What role does air resistance play in affecting your data?Air resistance reduces the effective range3. Discuss any additional sources of error, and suggest how these errors could be reduced if you were to redesign the experiment.setting of theprojectile launcher affects the set angle after each launch. The launcher should be held in a fiexedv angle fixture 4. How could kickers on a football team use their knowledge of physics to better their game? List at least two other examples in sports or other applications where this information would be important or useful.The kickers should apply physics to try and kick the ball at 45 degrees so that it goes for the furthest distance. This information could also be used in athletics to throw javeline. The military could also apply the concept of projectiles to aim a target using missiles or guns.© 2014 eScience Labs, LLC.All Rights
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