A block is released from rest, at a height h, and allowed to slide down an inclined plane.
There is friction on the plane. At the bottom
of the plane, there is a spring that the block
will compress. After compressing the spring,
the block will slide up the plane to some maxi-
mum height, ha, after which it will again slide
back down.
How much work is done on the block be-
tween its release at height h and its ascent to
its next maximum height?

stands for electromotive force and it is measured in volts. despite its name, it is not actually the force in the sense of being a "pushing" or "pulling" (not measured in newtons).an equation that relates emf,  ℰ,  to a battery's terminal voltage, v, current, i, and internal resistance, r, is    ℰ = v + irin this case, the emf can be interpreted as a voltage—a difference in electric potential.i would not say that it would be considered an energy. if emf can be defined as the energy/work per a unit charge from a battery or other electric source, then it is not strictly energy.