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.
According to Newtonâs first law, the motion of an object does not change if the net force acting on it is zero. 3. If there were no friction, a moving object would keep moving, even if no other force were applied to it. 4. Inertia is two or more forces acting in opposite directions.