Explanation:
When an object moves up in the air, kinetic energy (KE) is converted into potential energy (PE). When kinetic energy is exhausted, the object will stop rising and begin to descend. But the KE lost is all converted to PE.
1. Both kinetic energy when the gymnast leaves the trampoline and the potential energy achieved at the highest point are the same and equal to
PE(at highest point) = KE (when leaving trampoline)
= (mv^2)/2 = 60 kg * (7 m/s)^2 /2 = 1470 joules
2. Since the PE at the highest point is 1470 and equals mgh, we have
60*9.81*h = 1470 joules
Solve for h
h= 1470/(60*9.81) = 2.50 m
