Animation Examples of Kinetic and Potential Energy

Roller Coaster Energy is conserved throughout the ride and is merely being changed from K.E. to P.E. and vice versa Notice that the Total Mechanical Energy remains constant during the animation

Pendulum Example At the highest point on each side, the Kinetic Energy is equal to zero The Energy is being converted back and forth from K.E. to P.E.

Conservation of energy Section 5-3 Conservation of energy

Conserved Quantities The mass of the light bulb is constant This is true if the light bulb is whole or in pieces We will be applying this same principle to energy

Mechanical Energy Definition: the sum of kinetic energy and all forms of potential energy ME= KE + ∑PE Mechanical energy is often conserved

Energy Classification

Conservation of Mechanical Energy In the absence of friction, the total mechanical energy remains the same This is called the conservation of mechanical energy MEi = MEf Initial mechanical energy = Final mechanical energy

ME cont. Energy conservation occurs even when acceleration varies Example: The Roller Coaster Animation Exception to the rule: Mechanical energy is not conserved in the presence of friction Sanding block in Figure 5-12