How much potential energy does the ball have when it reaches the top of its ascent

Its has the most it will have during its descent because as it goes down the kinetic energy replaces potential

At the top of its ascent, the ball has potential energy equal to

(its weight) times (the height of its ascent).

If we knew either of those quantities, then we could give you

a number for its potential energy. But the question has no

given information.