Question

if action is always equal to reaction, explain how a horse can pull a cart​

Answer 1

Explanation:

when the horse applies a force on cart, the cart also applies a force on the horse. but these two forces cancel out each other. but there is another force that horse applies on the ground. and this force is opposed by frictional force. since the horse pushes the ground , the ground also pushes the horse on the opposite direction . this makes the hosre move with cart.

Answer 2

Explanation:

Horse pushes the ground in backward direction. In reaction to this, the horse moves forward and cart moves along with horse in forward direction.

In this case when horse tries to pull the cart in forward direction, cart pulls the horse in backward direction, but because of the unbalanced force applied by the horse, it pulls the cart in forward direction.