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it experiences a net restoring force due to gravity:

F_{r} = - mgsin .
| (16) |

For small angles, sin , providing is expressed in radians (try it on your calculator for = 0.1,0.5,1.0 radians). In terms of radians,

= *radians*

*F*_{r} = - .

T = 2 = 2.
| (17) |

- In this small angle approximation, the amplitude of the pendulum has no effect on the period. This is what makes pendulums such good time keepers. As they inevitably lose energy due to frictional forces, their amplitude decreases, but the period remains constant.

10/9/1997