Aboy throws a ball straight up with a speed of 21.5 m/s. the ball has a mass of 0.19 kg. how much gravitational potential energy will the ball have at the top of its flight? (assume there is no air resistance.)

So first you have to determine what the maximum height of the object will be.
21.5-9.8t=0
This equation will give you the time at which the ball hits max height
t= 2.194 sec
So now use the time and plug it in to the velocity equation so 21.5•2.194= 47.171
So the max height is 47.171 which we can use for the gravitational potential energy
The weight (.19) times the height (47.171) is 8.96249 and that is the answer