A girl swings on a playground swing in such a way that at her highest point she is 3.7 m from the ground,

while at her lowest point she is 0.7 m from the ground. What is her maximum speed? The acceleration of gravity is 9.8 m/s. In meters per second.

I am very confused and am having a lot of trouble with this question. Can anyone help?

Hi Tim, the potential energy when at height 3.7 m will be m g *3.7
When she reaches the lowest position the potential energy = mg * 0.7
Hence the energy converted in KE = mg*(3.7-0.7) = 3 mg
KE = 1/2 m v^2
So v^2 = 6g
Or v ie the maximum velocity or speed = ./6g = 7.67 m/s