Hi PLEASE SOLVE USING CHANGE IN ENERGY (I know the answer but I had trouble getting the correct answer when solving this problem using work)

This problem involves a hypothetical alien planet with both a gravitational field and an electric field. Long, long ago on a planet far, far away, a physics experiment was carried out. First, a 0.250-kg ball with zero net charge was dropped from rest at a height of 1.00 m. The ball landed 0.552 s later. Next, the ball was given a net charge of 7.75 C and dropped in the same way from the same height. This time the ball fell for 0.680 s before landing. What is the electric potential at a height of 1.00 m above the ground, given that the electric potential at ground level is zero? You may assume that the electric field is uniform, the E field lines are vertical, and that air resistance is negligible.

assist: refer to potential energy in a field formula and electrical potential formula

thanks