Question

An ice skater standing on an icy surface pushes off a wall. The ice skater has a mass of 60 kg and exerts a force of 100 N on the wall. A rollerblader standing on a wooden floor pushes off a wall. The rollerblader has a mass of 90 kg and exerts a force of 100 N on the wall. Both people move after pushing on the wall and keep their bodies still, relying only on friction to stop.
How much force does the wall exert on the ice skater, and why?



0 N; the wall does not move when the ice skater pushes off.

100 N; the force exerted by the wall is equal to the ice skater’s push.

Greater than 100 N; the force exerted by the wall redirects the motion of the ice skater.

Between 0 N and 100 N; the icy surface decreases the force needed to move the ice skater.

Answer 1

It's 100 N, which follows directly from Newton's third law - for every force acting on a body, that same body exerts a force equal in magnitude in response.