1. The problem statement, all variables and given/known data A .300-kg ball is thrown vertically upward with an initial speed of 10.0 m/s. If the initial potential energy is taken as zero, find the ball's kinetic, potential, and mechanical energy at it's initial position. 2. Relevant equations 1/2mv(f)^2 + mgy(f) = 1/2 mv(i)^2 + mgy(i) 3. The attempt at a solution I understand how to solve the problem. From my equation I've plugged in the 10 m/s for the inital and zero for the potential. Is potential energy zero because the book said it was? What I don't understand is why potential energy is zero when initial velocity is 10 m/s. If there is initial velocity shouldn't there be a numerical quality in the y direction? To be more clear, if an object is initially moving at a certain rate, shouldn't the ball have left the person's hand and given the ball some sort of height even a little bit?