EngArc - L - Mechanical Energy and Conservation of Mechanical Energy

Mechanical Energy and Conservation of Mechanical Energy

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The mechanical energy E_mech of a system is the sum of its potential energy U and the kinetic energy K of the objects within it.

Details

The mechanical energy E_mech of a system is the sum of its potential energy U and the kinetic energy K of the objects within it:

E_mech = K + U

This lesson will only consider what happens to this mechanical energy when only conservative forces cause energy transfers within the system — that is, when frictional and drag forces do not act on the objects in the system. Also, it is assumed that the system is isolated from its environment; that is, no external force from an object outside the system causes energy changes inside the system.

When a conservative force does work W on an object within the system, it transfers energy between kinetic energy K of the object and potential energy U of the system.

Mechanical energy is the movement of machine parts. Wind-up toys, grandfather clocks, and pogo sticks are examples of mechanical energy. Wind power uses mechanical energy to help create electricity.