Simple Pendulum

Simple Pendulum

Warm-up: Phet

Simple Pendulum

• Made of a mass m and a string or rod of length L

• Harmonic Motion because of the restoring force that pulls it back towards equilibrium.

• WHere does the restoring force come from?

• the sin component of weight

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Period of a pendulum

• Depends on neither mass or amplitude

• depends strictly on length and the force of gravity

•  $T=2\pi\sqrt{\frac{L}{g}}$  

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Discussion:

Why don’t amplitude(distance from equilibrium) and mass have any effect on period?

Discussion

Why does length from axis have the effect on a pendulum that it does?

Resonance

• Many things run only because of driven oscillations( cycles cause by an outside force.

• Natural frequency- frequency an object oscillates by itself

• A system driven at its natural frequency is in resonance- they will often have large amplitudes

• The resonance of objects effects how they are built- materials science is very important for engineering