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## Homework Statement

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?

## Homework Equations

Power=Work/Time

Work=Change in KE

## 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!