Question

3. If action is always equal to reaction force, explain how a horse can pull a cart.

Answer 1

Answer:

According to Newton's third law of motion action force is equal to reaction but acts on two different bodies and in opposite directions.

Explanation:

When the horse pushes the ground the ground reacts and exerts a force on the horse in the forward direction . This force is able to overcome the friction force of the cart and it moves

Answer 2

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When the horse walks in the forward direction (with the cart attached to it), it exerts a force in the backward direction on the Earth. An equal force in the opposite direction (forward direction) is applied on the horse by the Earth. This force moves the horse and the cart forward.

The velocity at which the horse can move by applying a force on the earth depends on the mass of the horse (and the cart attached to it). The heavier the cart, the slower the motion of the horse (for a given amount of force applied by the horse on the Earth). If the cart is too heavy, the force exerted by the horse on the Earth will be insufficient to even overcome the force of inertia. In this case, the horse will not be able to pull the cart.