Energy enables an object to do work. work is done when a) no force is put on an object, and the object does not move in any direction. b) a force is put on an object, but the object does not move in any direction. c) a force is put on an object, and the object moves in the direction of the force. d) no force is put on an object, but the object moves at varying speeds in a random direction.

Work is = to force*displacement which give W=F*d so if 0 force is put on an object the W= 0*d = 0 work, so a is out. for b if force is put on the object but it does not move then W=F*0 (no displacement)= 0 so if there is no movement then no work is done so b is out. for D since W=F*d also says no force is put on the object so W=0*d which would equal 0 work so D is also out. but for c W=F*d and if we assume that F is not = to 0 and d is not equal to 0 then the equation W=F*d would give a number other than 0 so only c will result in a nonzero value for work. in all other cases no work is done. As a side note if a force is applied to an object and the object goes around the world and ends up and the same place that it started then since Work is equal to force * displacement there will still end up with no work being done since W=F*0=0 work (since the object ended up in the same place it started even though it moved the displacement is still 0, so work done will still be 0.