How much one wave lags behind another (radians, degrees or fraction of a cycle)

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What does a displacement time graph look like?

Displacement, x, varies as a cosine or sine graph with the maximum value of A (amplitude)

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What does a velocity time graph look like?

Velocity, v, is the gradient of the displacement time graph with the maximum value of (2pif)A (where f is the frequency of the oscillation)

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What does an acceleration time graph look like?

Acceleration, a, is the gradient of a velocity-time graph. It has a maximum value of (2pif)^2A

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What are forced Vibrations?

A periodic external driving force which causes a system to vibrate

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What is the frequency of a driving force called?

Driving frequency

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What is a free vibration?

Involves no transfer of energy from the oscillating object to surroundings, the object will oscillate at natural frequency at constant amplitude.

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What is the phase difference if the driving frequency much less than the natural frequency

The two are in phase (0 or 2pi)

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What is the phase difference if the driving frequency is higher than the natural frequency?

The two are out of phase/antiphase (pi or 180 degrees) because oscillator can’t keep up

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What is resonance?

Driving frequency approaches natural frequency. The system gains more and more energy from driving force so system vibrates with rapidly increasing amplitude.

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What is natural frequency?

Frequency which a system oscillates when there is no periodic driving force

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What is the phase difference at resonance?

90 degrees out of phase of pi/2 radians

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Examples of resonance

Radio tuned so electric circuit resonates at the same frequency as radio station, swing resonates if someone pushes at natural frequency

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What is light damping?

Takes long time to stop oscillating, small decrease in amplitude with every period

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What is heavy damping?

Takes less time to stop oscillating, amplitude gets much smaller each period

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What is critical damping?

Returns to the equilibrium in the fastest time.

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What effect does damping have on resonance peaks?

Light damping have sharp resonance peaks, becomes flatter as damping increases.

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What is Damping?

System loses energy to surroundings due to frictional forces. Causes a decrease in amplitude which eventually stops the oscillations.

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What is overdamping?

too much heavy damping which causes the system to take longer to return to the equilibrium

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Other cards in this set

Card 2

Front

What does a displacement time graph look like?

Back

Displacement, x, varies as a cosine or sine graph with the maximum value of A (amplitude)

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