A 100 kg cart accelerates at 0.50 meters per second squared west as the horse exerts a force of 60 newtons west on the cart what is the magnitude of the force that the car exerts on the horse

Newton's third law of motion (also known as lar of action-reaction) states that when an object A exertes a force on another object B, object B also exerts a force on object A equal and opposite to the first force. If we apply the law to this problem, we can say that the force exerted by the car on the horse is equal to the force exerted by the horse on the car, so its magnitude is 60 N.