Respuesta :
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.
