A helicopter lifts a 72kg astronaut 15m vertically from the ocean (from rest) by means of a cable. The acceleration of the astronaut is g/8.
a) How much work is done on the astronaut by the force from the helicopter. (cable)
b) How much work is done on the astronaut by the gravitational force?
c) What is the kinetic energy and d) speed of the astronaut just before he reaches the helicopter?