PH-UY 1013 Lecture Notes - Lecture 5: Closed System
Document Summary
Energy an object has because of its motion. Symbol is ke and unit is joule. Law of conservation of energy- states that the total energy of a closed system remains constant. Closed system- one in which no external forces act and no external work is done on or by the system. Energy may be transferred b/w the objects in the system or be converted within the system from one form to another, but total amount of energy within system cannot change. Sum of ke and pe = total mechanical energy. If there is no loss of energy due to friction or air resistance, the gain in ke equals loss in pe and loss of ke equals gain of pe. For a freely falling object initially at rest, pe(top) = ke(bottom) or mg=1/2mv2. Work done against air resistance or friction (wf) is converted into heat or internal energy (q) Total energy= pe +ke + internal energy.
