Question

You are standing in an elevator that is accelerating upward at 1m/s². Which of the following pairs of forces is an action-reaction pair that has to be exactly equal and opposite to each other? A The force of gravity on you and the force that the floor of the elevator exerts on you. B The force that the floor of the elevator exerts on you and the force that you exert on the floor of the elevator. C The force of gravity on you and the force that you exert on the floor of the elevator. D None of these pairs because acceleration requires an unbalanced force.

Answer 1

B The force that the floor of the elevator exerts on you and the force that you exert on the floor of the elevator

Step-by-step explanation:

A. is incorrect because the force of gravity on you will always stays the same while the force of the elevator exerts on you changes as it takes you upward

B. is correct in accordance to Newton's 3rd law of action and reaction forces.

C. is incorrect because gravity force stays the same while the force that you exerts on the floor change as elevator moving upward.

D. is incorrect although it states Newton's 1st law. However there can still be pair of forces (part B) that could counter balance each other among other forces.