A baseball pitcher throws a ball straight up into the air at a speed of 21.0 m/s. In the process, he moves his hand through a distance of 1.40 m. If the ball has a mass of 0.150 kg, find the force he exerts on the ball to give it this upward speed. My problem is that I don't know where to use the 1.40m. I assume I have to find the acceleration somehow and then plug it into F=ma but every method I try seems to fail. Thanks for the help.