Question

Calculate the amount of gravitational potential energy at the top of each hill

and at the bottom of each valley. Be sure to convert your distance
measurements to meters. Use an approximated value of 58.0 g for the mass
of the tennis ball, and 9.81 m/s2
as the acceleration due to gravity. Record
your calculations in joules in the Kinetic and Potential Energies table.

Answer 1

5.5

Explanation: your welcome

Answer 2

the gravitational potential energy has the formula:
PE = mgh
where PE is in joules
m is the mass of the object in kg
g is the acceleration due to gravity
h is the height in m

since you did not give the value of h, i cannot fully answer your quesstion.
PE = (58/1000 kg) (9.81m/s2) h
PE = 0.57h
just substitute the value of h in the equation