A man jumps off of a paddle board into a lake as shown below.

Question

If the man's feet pushing the paddle board is the action force, then which of the following is the reaction force?
A.
the paddle board pushing down on the water
B.
water pushing up on the paddle board
C.
the paddle board pushing back on the man's feet
D.
water pushing up on the man's feet

Answer 1

According to Newton's third law of motion, for every action force, there is an equal and opposite reaction force.

In this scenario, if the man's feet pushing down on the paddle board is the action force, then the reaction force would be that the paddle board exerts an equal and opposite force back on the man's feet.

Therefore, the correct answer is:

C. the paddle board pushing back on the man's feet.