Question

If action is always equal to the reaction. Explain how a horse pull a cart

Answer 1

Dear student,
Action is equal and opposite to the reaction. Yes. Even in the case of a horse pulling the cart. The horse can pull the cart forward and walk if and only if the ground it is walking on pushes its hoof with a force. That force is friction.In the absence of that reaction force called friction, it would be like walking on a smooth ice floor.

Regards.