Question

A the top of a hill, an athlete on a skateboard has X joules of mechanical energy. How much mechanical energy will she have at the bottom of the hill? Ignore the effects of friction.

Answer 1

At the bottom also she will have X joules of energy
Bcoz mechanical energy remains conserved when there is no external force acting

Answer 2

At the bottom also she will have X joules of energy, because mechanical energy remains conserved when there is no external force acting.

Mechanical energy is the sum of the potential and kinetic energies in a system.

The principle of the conservation of mechanical energy states that the total mechanical energy in a system remains constant as long as the only forces acting are conservative forces.