Potential Energy and Conservation of Energy

Conservative Forces When the system configuration changes, the force does work (W1) transferring energy. When the configuration change is reversed the force reverses energy transfer, doing work (W2) in the process

Nonconservative Forces A force that is not conservative is called nonconservative force. Kinetic friction and drag forces are nonconservative.

Path Independence of Conservative Forces W1 W1 A B A B W2 W2

Gravitational Potential Energy m h m

Spring Potential Energy k x k

Conservation of Mechanical Energy The mechanical energy (Emec) of a system is When no external forces act on a system Conservation of Mechanical Energy

Potential and Kinetic Energy U K U K U K U K U K

Power Energy can be transferred from one form to another through the process of work. The rate at which work is done is called power Average power Instantaneous Power

Work done against gravity h m

Work done against gravity cm h M Work required to lift one end

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