So, here is the problem: I have a .535kg ball that I drop from an unkown height, to create an impact with a force of 6.8 Joules. I need to figure out what height to drop the ball from. I figure it has something to do with accleration due to gravity and Netwons law F=mA or possibly a kinetic energy equation. Right now I am scrambling to find the answer. Can anyone please help?