Gavin learns in science class that small objects such as meteoroids and debris can move through space at such high speeds that they can damage or puncture the sides of space vehicles. He decides to design an experiment based on this information.

Question

Gavin uses an empty shoe box, a sheet of paper towel, and tape to build a model of a spacecraft. Then, he shoots a pea at the paper towel part of the model using a straw pea shooter.

For his first trial, Gavin shoots a 3.0-gram pea at the model. Its speed is measured at 12 meters per second as it leaves the straw. The pea does not break the paper towel, but it bounces back off and lands on the ground.

Which of the following best explains why the pea bounced off the paper towel?
A.
When the pea hit the paper towel, the paper towel applied an equal but opposite force on the pea.
B.
When the pea hit the paper towel, the paper towel absorbed the force of the pea but did not apply a reaction force.
C.
When the pea hit the paper towel, the paper towel applied a smaller force in the opposite direction on the pea.
D.
When the pea hit the paper towel, the paper towel applied a greater force in the opposite direction on the pea.

Answer 1

The best explanation for why the pea bounced off the paper towel is:

A. When the pea hit the paper towel, the paper towel applied an equal but opposite force on the pea.

This explanation is aligned with Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. When the pea strikes the paper towel, the towel exerts an upward force on the pea that is equal in magnitude but opposite in direction to the force exerted by the pea on the towel. As a result, the pea bounces back after the collision.