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Cause and Effect — work, energy and machines
Cause
A force does work on an object by displacing it in the direction of the force
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Work-energy theorem
the work done equals the change in the object's energy
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Effect: energy is gained, stored or transferred — and machines let us apply that work more conveniently, never creating energy
- Work
- Work is done by a force on an object when the force displaces the object in the direction of the force.
- Energy
- An object having the capacity to do work is said to possess energy.
- Work-energy theorem
- The work done on an object or a system is equal to the change in its energy.
- Kinetic energy
- The energy possessed by an object due to its motion; K = ½mv².
- Potential energy
- The energy stored by an object due to its deformation, or in a system of objects due to their relative positions; gravitational PE = mgh.
- Power
- The rate at which work is done; P = W/t, measured in watts.
- Simple machines
- Devices that make work easier by changing the magnitude or direction of the force, though they do not reduce the total work done.
