Draw a system diagram and free-body diagram for a ballistics cart and ball when the ball is fired. Use this to explain Newton's third law and the relative motions of the cart and ball. Why are two free-body diagrams necessary for this situation? [2 C] [3 TfI] [2 KJU] Newton's third law is often misunderstood in large part because of the use of the terms \"action\" and \"reaction\" forces. In reality, either force could be considered an \"action\" or \"reaction\