What forces act on a thrown baseball? (Assuming the baseball motion is an upside down parabola). What forces act on a thrown baseball? 1) After the first fraction of second after it leaves your hands? 2) After it leaves your hands and at the top of it motion (top of the parabola). Some people think that the force of the hand continues to act throughout the motion. Other think that the only force acting throughout the motion is force of gravity. Who is correct from an experiment point of view? I think after the few fractions of the second when the ball leaves the hand, there is the ball’s weight acting on it, and the force of the hand. At the middle of the parabola there is only the weight = mass x (9.81 m/s^2) acting on it. what about the air?. From an experience point of view I think that they are both wrong, that hand force act on the ball at the beginning of its motion and after the hands force fades the gravity force takes over. Am I correct?