1. The problem statement, all variables and given/known data A helicopter, starting from rest, accelerates straight up from the roof of a hospital. The lifting force does work in raising the helicopter. (a) What type(s) of energy is (are) changing? Is each type increasing or decreasing? Why? 2. Relevant equations Power=Work/Time Work=Change in KE 3. The attempt at a solution a) I would think that potential and kinetic energy are both changing; both increase because the helicopter gains altitude (increasing PE) and increases velocity (increasing KE). Is this correct? I know that in a situation where energy is conserved, one must decrease as the other one increases. I'm not sure whether this qualifies as an energy-conservative situation, though. b) The work-energy theorem. The work done by gravity + work done by helicopter = change in KE. Is this correct? Many thanks!