Lesson Review
Directions: Use the Projectile Motion Phet Simulation to answer the questions in the parts below.
Part A: Intro to Projectile Motion
Go to the Projectile Motion Phet Simulation. Click "Intro". Take a few minutes to click through the sim and explore the components. Practice using all the features.
1. Name all of the factors you think affect projectile movement (try to list at least five factors):
2. Experiment 1:
Choose one of the factors you listed in Question #1 and use the sim to test that factor. Your goal is to hit the target!
- Factor:
- Write your hypothesis regarding how the factor you’ve chosen will affect your ability to hit the target (If…then…because):
- What is your independent (test) variable?
- What is the dependent (outcome) variable?
- What variables will you keep constant?
- Once you have put all variables in place, fire away!
- Did you hit your target? Write three (3) conclusion sentences explaining your results.
3. Experiment 2
Choose one of the factors you listed in Question #1 and use the sim to test that factor. Your goal is to hit the target!
- Factor:
- Write your hypothesis regarding how the factor you’ve chosen will affect your ability to hit the target (If…then…because):
- What is your independent (test) variable?
- What is the dependent (outcome) variable?
- What variables will you keep constant?
- Once you have put all variables in place, fire away!
- Did you hit your target? Write three (3) conclusion sentences explaining your results.
With your lab partner, choose a different factor than the one above and propose a question to test that factor. Your goal is to hit the target!
4. Experiment 3
Choose one of the factors you listed in Question #1 and use the sim to test that factor. Your goal is to hit the target!
- Factor:
- Write your hypothesis regarding how the factor you’ve chosen will affect your ability to hit the target (If…then…because):
- What is your independent (test) variable?
- What is the dependent (outcome) variable?
- What variables will you keep constant?
- Once you have put all variables in place, fire away!
- Did you hit your target? Write three (3) conclusion sentences explaining your results.
5. Which factor appears most important in projectile motion? Explain your answer.
Part B: Projectile Vectors
From the main menu, click on “Vectors.”

Uncheck the “air resistance box”. Set the following: diameter = 0.8m, mass = 5 kg, initial speed = 18 m/s and the cannon angle = 45º. Click the “slow” button at the bottom to watch the simulation more carefully.
Click the box that says “acceleration vectors.” Fire the cannon. You will see the cannonball leave the cannon, with an acceleration vector.
6. What is the direction of the vector?
7. What does this vector represent?
8. What do you observe about the length of the vector throughout its flight?
9. What does this tell you about the direction and magnitude of the acceleration acting on the cannonball throughout its duration of flight?
10. What do you predict will happen to the acceleration vector if we change the angle of the cannon? Why do you think that?
Change the angle of the cannon to 65º. Fire the cannon at this new angle. Keep everything else the same. (Remember, click on the “slow” button to slow the simulation down)
11. What did you notice about the acceleration vector at this new angle?
12. What was different about the vector (if anything) compared to the 45º angle. Move the cannon back to 45º if you need to check or verify.
13. Was your prediction correct about the acceleration vector at this new angle?
Change the angle of the cannon to 90º. Fire the cannon at this new angle. Keep everything else the same. (Remember, click on the “slow” button to slow the simulation down)
14. What did you notice about the acceleration vector at this new angle?
15. What was different about the vector (if anything) compared to the 45º or 60º angle? Move the cannon back to 45º or 60º if you need to check or verify anything.
16. Summary: What have you discovered about the acceleration due to gravity of an object in flight with regards to the angle of launch?
Change the angle of the cannon to 45º. Click the “slow” button. Fire the cannon and observe the acceleration vector. Now change the initial launch speed to 25 m/s. Fire the cannon again.
17. What did you observe about the acceleration vector when you fired it at the new speed? Was it any different from the initial speed?
Click the yellow erase button and unclick the acceleration vectors box. Click the “velocity vectors” box. Click on “components” just above it. This will track velocity in both the x and y directions.
Set the cannon to 60º and the initial velocity to 15 m/s. Click “slow” if you haven’t already. Fire the cannon. Click erase and fire multiple times if necessary.
18. What do you notice about the velocity vector in the y direction? Describe what happens to its length and direction throughout the flight? Be specific.
19. At what point does it seem like there is no velocity vector in the y direction?
20. Describe in your own words what is happening to the velocity in the y direction as the cannonball leaves the cannon and flies through the air.
21. What do you notice about the velocity in the x direction?
22. Why do you think this isn’t changing? (Hint: What is affecting the velocity in the y direction, but not the x direction?)