I assume that the ball is stationary (v=0) at point B, so its total energy is just potential energy, and it is equal to 7.35 J.
At point A, all this energy has converted into kinetic energy, which is:

And since K=7.35 J, we can find the velocity, v:
500 ml = 0.5 liters. that's what i'm getting
hope it helps
As the temperature increases the kinetic energy of the molecules increases, if u add more heat you get more kinetic energy.
One does not simply should you do you should