Gravity Playing with units
A mass of 10000000 milligram is released from a height of 4000 centimetre above the surface of the Earth .
Calculate its mechanical energy when it is at 2000 centimetre, above the surface of the Earth.
DETAILS AND ASSUMPTIONS:
1) Take the acceleration due to gravity as \[g = 10 m / s^2\]
2) Provide your answer in Joules.