Practice identifying Newton's Third Law force pairs, explaining action and reaction forces, and applying them to real-world physics situations.
Read each problem carefully. Identify the objects involved in each force pair and explain your reasoning. Show your work in the space provided when calculations are needed.
Action and reaction forces in everyday situations
Physics - Grade 9-12
- 1
State Newton's Third Law in your own words. Include what is meant by an action-reaction force pair.
- 2
A student pushes on a wall with a force of 80 N to the east. What force does the wall exert on the student?
- 3
A rocket engine pushes hot gases downward. Explain how Newton's Third Law helps the rocket move upward.
- 4
A 0.20 kg tennis ball hits a racket. During contact, the racket exerts a 120 N force on the ball. What force does the ball exert on the racket?
- 5
Two ice skaters push off from each other. Skater A has a mass of 50 kg, and Skater B has a mass of 75 kg. During the push, which skater experiences the larger force? Explain.
- 6
In the same ice skater situation, why does the 50 kg skater accelerate more than the 75 kg skater if the forces are equal?
- 7
A book rests on a table. Identify the Newton's Third Law partner force for the force of the table pushing upward on the book.
- 8
A book rests on a table. A student says, 'The upward normal force and the downward weight of the book are a Newton's Third Law pair.' Explain why this statement is incorrect.
- 9
When you walk forward, your foot pushes backward on the ground. What force helps you move forward?
- 10
A swimmer pushes water backward with her hands. Use Newton's Third Law to explain how she moves forward.
- 11
A car tire pushes backward on the road as the car accelerates forward. Identify the reaction force and explain its role.
- 12
A 60 kg astronaut in space pushes a 10 kg tool with a force of 18 N to the right. What force does the tool exert on the astronaut, and in what direction?
- 13
For the astronaut and tool in the previous problem, calculate the acceleration of the astronaut caused by the tool's force.
- 14
A bug hits the windshield of a moving truck. Compare the force of the bug on the truck with the force of the truck on the bug.
- 15
A student fires a ball from a spring launcher. The launcher pushes the ball forward with a force of 35 N. Identify the action-reaction pair and describe why the launcher recoils.