A horse exerts 500 N of force on a heavy wagon. The wagon pulls back on the horse with an equal force. The wagon still accelerates because

Question

Quizplus · Accepted Answer

The wagon accelerates because the force the horse exerts on the wagon is not balanced by an equal and opposite force acting in the same system. The action-reaction forces described are equal in magnitude and opposite in direction, but they act on different objects (Newton's third law), so they do not cancel each other out in terms of causing acceleration. The unbalanced force on the wagon (from the horse) is what causes it to accelerate.

A Horse Exerts 500 N of Force on a Heavy