I'm unsure as to if you study Physics. But there are definitions for each word in the Newtonian world in the context of Physics. Power = The rate of doing work (expending energy). Force = An object that has a mass (kilograms) and is accelerating (rate of change of velocity[speed]). A force causes something to accelerate in a direction. It is known as the "Power behind something". Mass = It has weight(weight is a force) when acted upon gravity - (Kilograms) Energy = A potential to do work (expend energy). There are many types of Energy: Kinetic, Potential, Elastic, Electrical, Nuclear and so on. Acceleration = The rate of change of velocity. It measured in Metres per second, per second. All of those words can be used with a different context, such as a description, in order to make the writing more rhetoric. You could say "Wow, that child has a lot of energy.", or "That man must have a lot of power in those arms.". Compared to "Wow, that child is moving a lot.", or "That man is strong.", using Power, Force, and the others, makes the writing more interesting and open to the readers imagination. It makes it more rhetoric through the use of creative expression. I hope this helped in some way, feel free to ask me for anything you are not sure of.