Projectile Motion

The following activity allows you to use a computer simulation to explore the effects of mass, launch velocity, air resistance, and launch angle on projectile motion.

To access this activity, please visit: https://phet.colorado.edu/. Search for Projectile Motion (HTML5). Click Play, then Lab.

Set-up:

1. Be sure that the box titled "Air Resistance" is NOT checked. We will investigate this effect on projectile motion later.

EXPERIMENT A: What is the effect of MASS on the motion of a projectile?

2. Set the following parameters:

Initial Speed= 15 m/s; Angle = 45^o; mass = 0.05 kg (golf ball)

3. Press the Firebutton to launch your first projectile. At thetop of the screen, click and drag the measurement device (with the bull's eye) out of the toolbox. To record projectile data, center the bull's eye on a point along the projectile path. Data for the golf ball has been done for you as an example.

4. Repeat steps 1-2 using three other objects (masses). Do not change any other variables. Use the zoom buttons to view the projectile's trajectory (if needed). (After you run a few simulations you may question whether or not it is working correctly. The answer is "Yes, it is working correctly!")

Type of Projectile	Mass of the Projectile (kg)	Maximum Range (distance) (m)	Maximum height (m)	Total Time (seconds)
Golf ball	0.05	22.92	5.93	2.2

Questions:

1. Identify the following variables in this experiment: Control: Independent: Dependent:
2. What affect does mass have on the motion characteristics listed in the table above? Explain.
3. Recall that you launched each object, regardless of mass, at the SAME initial speed. Do you think the force applied to launch each mass was also the same? Explain your answer using Newton's Laws of Motion.
4. How much time does it take the projectile to reach its Maximum Height? How does this amount of time compare to the total time?

EXPERIMENT B: What is the effect of INITIALVELOCITY on the motion of a projectile?

1. Refresh the simulation and set the following parameters:

Initial velocity = 10 m/s; Mass = 5 kg (pumpkin); Angle = 45^o

2. Press the Firebutton to launch your first pumpkin. Use the measurement device to record maximum range (distance), maximum height, and total time. Use the zoom buttons to view the projectile's trajectory (if needed). Data for the first launch has been done for you as an example.

Repeat steps 1-2 using four other initial velocities. Do not change any other variables.

Initial Velocity (m/s)	Maximum Range (m)	Maximum Height (m)	Total Time (s)
10	10.19	2.55	1.44
15
20
25
30

1. Identify the following variables in this experiment: Control: Independent: Dependent:
2. When the velocity increases, which of the data table measurements of also increases?
3. Predict how the initial velocity and final velocity for each launch compare. Explain your reasoning.

EXPERIMENT C: What is the effect of AIR RESISTANCE on the motion of a projectile?

1. Refresh the simulation and set the following parameters:

Mass = 0.15 kg (baseball)

2. Input the data in the table below to simulate each projectile.By default, the air resistance is off (unchecked). To consider air resistance, check the box next to air resistance. Press the Firebutton to launch the first projectile. Usethe measurement device to record maximum range (distance), maximum height, and total time. Use the zoom buttons to view the projectile's trajectory (if needed). Data for the first launch has been done for you as an example.

Complete the data table for each projectile scenario.

Air Resistance (yes or no)	Initial Velocity (m/s)	Angle (degrees)	Maximum Range (m)	Maximum Height (m)	Total Time (s)
Yes	10	35	9.22	1.64	1.16
No	10	35
Yes	10	65
No	10	65
Yes	20	35
No	20	35
Yes	20	65
No	20	65
Yes	20	90
No	20	90

1. What seems to be the over-all effect of air resistance on these characteristics of projectile motion:(Answer with: increase, decrease or no effect.) Maximum Range: ____________ Maximum Height:____________ Total Time ("hang time"): ___________