13.2.1. A cannon fires a ball vertically upward from the Earth’s surface. Which one of the following statements concerning the net force acting on the ball at the top of its trajectory is correct?a) The net force on the ball is instantaneously equal to zero newtons at the top of the flight path. b) The direction of the net force on the ball changes from upward to downward. c) The net force on the ball is less than the weight, but greater than zero newtons. d) The net force on the ball is greater than the weight of the ball. e) The net force on the ball is equal to the weight of the ball.