In order for work to be done?

Question

(A) kinetic energy must be changed to potential energy (B) potential energy must be changed to kinetic energy (C) a machine must be used.

Answer 1

A lake in the mountain represents potential energy. When its water falls in a turbine, it is changed to kinetic energy that is used to spin an alternator that generates electricity that can be used to vacuum clean your home. Then ... the work is done! :-)

Answer 2

B) potential energy must be changed to kinetic energy

Potential means it has the ability to change - kinetic is the change of state of potential energy

Answer 3

work is said to be done when a force moves over a distance - so giving the formula m x g x h. Geberally when work is done potential energy as gained as work = P.E = mgh.

so the most suitable of the given answers is answer (A)