Select the situations from the list below in which mechanicalenergy is conserved.
A ball sliding down a hill with friction.
The Moon orbiting the Earth.
A ball sliding down a frictionless hill.
A child swinging on a frictionless swing, ignoring airresistance.
A ball that is dropped from a certain height and bounces back toa lower height.
An ice skater gliding along the ice.
Someone else posted this but the answer isn't correct.
