Public School, Deer Creek Minnesota, 1918 LakesnWoods.com Postcard and Postcard Image Collection - click image to enlarge Aerial view, Deer Creek Minnesota, 1972
Whenever work is done upon an object by an external force, there will be a change in the total mechanical energy of the object. If only internal forces are doing work (no work done by external forces), there is no change in total mechanical energy; the total mechanical energy is said to be conserved.
Mechanical Energy is the energy that an object has due to is motion or position, this can be either kinetic energy or potential energy. Non Mechanical Energy on the other hand is energy that does not fall into the category of energy from position or movement.