Explanation: According to Newton's third law of motion, when a rock strikes and exerts force on a nail, the nail will also exert the same amount of force but in opposing direction with the rock.
2. C. the second object exerts an equal and opposite force to the first object
Explanation: When one object exerts a force on another object, the second object exerts a force on the first object that is equal in magnitude, but opposite in direction; for every action, there is an equal, but opposite reaction; called the law of action-reaction.
3.D. All of the above
Explanation: A swimmer swimming forward: The swimmer pushes against the water (action force), the water pushes back on the swimmer (reaction force) and pushes her forward.
4.B. only when there is motion
Explanation: for every action force there is an equal (in size) and opposite (in direction) reaction force. Together, these two forces exerted upon two different objects form the action-reaction force pair.
Answers & Comments
Answer:
1. B. exerts an equal force back on the rock
Explanation: According to Newton's third law of motion, when a rock strikes and exerts force on a nail, the nail will also exert the same amount of force but in opposing direction with the rock.
2. C. the second object exerts an equal and opposite force to the first object
Explanation: When one object exerts a force on another object, the second object exerts a force on the first object that is equal in magnitude, but opposite in direction; for every action, there is an equal, but opposite reaction; called the law of action-reaction.
3. D. All of the above
Explanation: A swimmer swimming forward: The swimmer pushes against the water (action force), the water pushes back on the swimmer (reaction force) and pushes her forward.
4. B. only when there is motion
Explanation: for every action force there is an equal (in size) and opposite (in direction) reaction force. Together, these two forces exerted upon two different objects form the action-reaction force pair.
5. A. the force is doubled
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