The simple machines all require human energy in order to work. For example, when you push on the locomotive in the Museum, you actually are not doing work, because you cannot move it. Work consists of two parts. The other is the distance over which the force is applied. Force X Distance.
Work is measured in joules.
Force is the pull or the push on an object, resulting in its movement. Force is measured in newtons. Distance is the space the object moves. It is measured in metres. When we say a machine makes it easier for us to do work, we mean that it requires less force to accomplish the same amount of work.