Newtons law Physics problem

Question

A father is pulling his child on a sled in the snow. According to Newton’s Third Law, the force the father exerts on the sled is equal to the force the sled exerts on the father but opposite in direction. How is it possible that the father can pull the child and sled forward?

Answer 1

Two many words in answer by J.D.

Newton's third law is about of interaction of two bodies. In your case it is the son and his father. But here we also have the third body - the earth. The father can pull the son forward because the force of friction for him less than for the child.

Answer 2

The third law states that you can't exert a force without the same magnitude of force being exerted back. That's just what forces are - they are interactions.

The second law (and the 1st law which is just a word version of the 2nd) looks at one body (not two) and determines how it moves given all the forces acting on it.

Sled has F of father's pull sideways. Up and down weight and normal force cancel (Child is just part of sled)

Father has same force pulling in the opposite direction as he pulls on the sled, but he also has traction from the friction responding to his pushing backwards on the ground (The ground's reaction force pushes him forward - If there is no friction with the ground, the father can't exert any force and can't move the sled)

The action/reaction pair of forces do not cancel because they are exerted on different bodies.