A coin mass 0.005 kg is dropped from a height of 3 m. How much mechanical energy does it have right before it hits the ground?

Mechanical energy equals the sum of potential and kinetic energy. During the process, all PE converts into KE, assuming air resistance is neglected. So, the mechanical energy does not change and is equal to the initial potential energy.

ME

=mgh

=0.005 x 9.81 x 3

=0.147J