SUCCEED

Modeling Projectile Motion

Objective: Students will learn about projectile motion and physics through modeling the path of an object that they have found broken on the ground.

Materials: Each student will need

• A pencil and paper
• A calculator
• A computer with internet access

The Stories

A glass object is broken on the ground. One person says it was thrown, the other said it was accidentally knocked down. Which is true? We have two conflicting stories. How can we tell who is lying?

• have students suggest reasons why one or the other might be lying
• encourage ideas considering the physical probability of the situation

How could we figure out if it's physically plausible?

• talk about modeling the situation

Modeling the Fall

Have students create sketches of what the fall should have looked like if the story were true.

• Discuss why the sketches look that way.
• What causes vertical motion?
• What causes horizontal motion?
• What happens when they're combined? Why isn't it linear?

Solving for the Unknown

  Horizontal: d=vt
  Vertical: d=vt+(1/2)at^2
  Where a=g and g=9.8m/s^2
  

Use vertical to solve for t when the initial velocity is 0. Use t to solve horizontal for initial velocity.

Have students work in groups to knock an object from various heights and calculate the initial velocity.

• Is this reasonable? What is a reasonable initial velocity?
• Given the data, who was likely lying?
• Using the dimensions, what was the initial velocity?
  • have students use the applet, then check the answer to see if it's correct
• Is that reasonable? Then who was probably lying?