I am having trouble with some of these questions: 1. A ball is held in a person's hand. a) Identify all the external forces acting on the ball and the reaction to each. b)If the ball is dropped, what force is exerted on it while it is failling? Identify the reaction force in this case. (Neglect air resistance) My Work: a) actions: downward gravity force exerted onto the ball upward normal force exterted by the hand on the ball reactions: upward gravity force exerted by the ball?? I think this is because the ball is on the hand while the gravitational force is acting upon it thereforce have an opposite upward gravitational force to make the net force zero? downward force exerted by the ball onto the hand b) If the ball is dropped, the only force exerted on it while falling would be the downward gravitational force. The reaction would be the upward gravitational force exerted by the ball on Earth. Why is this? If the force acting upon the ball while failling is the gravitational force, and there is no air friction, why would there be an upward gravitational force? Wouldn't the reaction be the acceleration of gravity(-9.8m/s^2)??