Potential and kinetic energy-falling body
(a) What is the potential energy of a mass of 1 kg at a height of 1 km above the earth? Express the answer in ergs and in joules, and refer the potential energy to the surface of the earth.
(b) What is the kinetic energy just as it touches the earth of a mass of I kg that is released from a height of 1 km? Neglect friction.
(c) What is the kinetic energy of the same mass when it has fallen halfway?
(d) What is the potential energy when it has fallen halfway? The sum of (c) and (el) should equal (a) or (b). Why?