Projectile Motion (Virtual Lab) Background In this experiment, you will investigate what variables, if any, affect the motion of a projectile. Since the equations of motion for a projectile are rather complicated, this investigation will be conducted virtually, with the aid of a Java applet. Mass of Projectile 1. Open the Projectile Motion applet. 2. Enter a velocity of 50.0 m/s and a launch angle of 45.0 degrees. These variables will remain constant through the procedure. 3. Fire the projectile with the different masses listed in Table 1. Record the statistics of the motion in each case. 4. Describe the shape of the path the projectile traces on the screen. 5. What affect does mass have on the motion of the projectile; i.e., which of the displayed statistics changes? Why do you think this is the case? 6. Do you think the force applied to the different masses would also be the same? Explain your answer using Newton’s laws of motion. 1 7. What amount of time do you estimate for the projectile to reach its maximum height? Initial Velocity of Projectile 1. Refresh the web page. Enter a mass of 5.0 kg and a launch angle of 45.0 degrees. These variables will remain constant through the procedure. 2. Fire the projectile with the different velocities listed in Table 2 and record the statistics. 3. What affect does velocity have on the motion of the projectile? 4. How do the initial and end velocities of the projectile compare for each launch? Launch Angle of the Projectile 1. Refresh the web page. Enter a mass of 5.0 kg and a velocity of 50.0 m/s. These variables will remain constant through the procedure. 2. Fire the projectile with the different launch angles listed in Table 3 and record the statistics. 3. At what angle was the maximum range (horizontal distance) reached? 4. At what angle was the maximum elevation achieved? 5. At what angle was the greatest “hang” time achieved? 6. Compare the maximum range (horizontal distance) reached for these pairs of launch angles. 10◦ and 80◦ 20◦ and 70◦ 2 7. What pattern is observed for these angles and their maximum ranges? 8. What is the sum of each set of paired angles? 9. Do you notice any other paired combinations in the data table that share the same maximum range? List them. 10. A projectile is launched at an initial speed of 50 m/s with a horizontal angle of 76◦ . Use the simulation to answer these questions: What is its range? State another angle that will produce the same range. 11. Does the simulation verify your prediction? 12. What is the sum of the two angles that produce this range? Air Resistance 1. Refresh the web page. Enter a mass of 5.0 kg. This is the only variable that remains constant in the procedure. 2. Fire the projectile with the different velocities and launch angles listed in Table 4 (note that some are these are with air resistance, while others are without). Record the statistics. 3. What seems to be the over-all effect of air resistance on these characteristics of projectile motion? Answer with increase, decrease, or none. Maximum range Maximum height Total time End velocity 4. Air Resistance is also known as what force? 3 Summary State the major ideas you learned about projectile motion from this virtual lab investigation. Data Projectile Mass (kg) Maximum Range [distance] (m) Table 1: Varying Mass Maximum End Elevation Velocity [height] (m) (m/s) Total Time (s) 1 5 10 20 Initial Velocity (m/s) Maximum Range [distance] (m) Table 2: Varying Initial Velocity Maximum End Elevation Velocity [height] (m) (m/s) 10 20 30 40 50 4 Total Time (s) Launch Angle (degrees) Maximum Range [distance] (m) Table 3: Varying Launch Angle Maximum End Elevation Velocity [height] (m) (m/s) 10 20 30 40 45 50 60 70 80 90 5 Total Time (s) Air Resistance Initial Velocity Launch Angle m/s (degrees) Yes 30.0 35.0 No 30.0 35.0 Yes 30.0 65.0 No 30.0 65.0 Yes 60.0 35.0 No 60.0 35.0 Yes 60.0 65.0 No 60.0 65.0 Yes 60.0 90.0 No 60.0 90.0 Table 4: Air Resistance Maximum Maximum Range Elevation [distance] [height] (m) (m) 6 End Velocity Total Time (m/s) (s)