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**preview**shows pages 1-3. to view the full**9 pages of the document.**PHYS 112 Review

Chapter 13: Oscillations about Equilibrium

Simple Harmonic Motion

- Non constant acceleration

- Periodic motion: motion that repeats itself

- Oscillatory motion: periodic motion that moves back and forth over the same path

Period (T): the time required for a motion to repeat, time required for one cycle of periodic motion

Frequency: the number of oscillations per unit time: f=1/T

Angular Frequency: w = 2πf = 2π/T

Position: x(t)=Acoswt

Velocity: v(t)=-Awsin(wt)

Acceleration: a(t)=-Aw2cos(wt) = -w2x(t)

Where A is the amplitude of motion, w is the angular frequency of motion, and f is the frequency of

motion

A linear restoring force will give you simple harmonic motion. The linear restoring force tries to push the

mass back to equilibrium position.

Hooke’s Law: F= -kx = ma

KE= ½mv2

PE= ½kx2

Energy doesn’t change when mass is doubled, however, maximum velocity does.

Chapter 14: Waves and Sound

Periodic disturbance – transfer of energy without transferring materials

2 kinds of waves: transverse and longitudinal

Transverse: disturbance is perpendicular to direction of propagation

Longitudinal: disturbance is parallel to direction of propagation

v: velocity of wave (constant for constant medium)

A: amplitude (height of disturbance)

λ: wavelength, repeated disturbance

f: frequency, number of full waves that pass a point

T: period, time for one wavelength to pass a point

v=distance/time=x/T=fλ

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Superposition principle: 2 waves travelling toward each other meet and pass through each other. Where

the waves overlap you see the sum of the two waves:

constructive interference (waves that give a larger amplitude), in phase, louder noise, r1=r2+nλ

destructive interference (waves that give a smaller amplitude), out of phase, quiet noise r1=r2+(n+1/2 )λ

Sound: in solid medium:

in fluid or gas medium:

When a sound wave passes from air to water, wave speed must change (different medium). However,

frequency does not change, as it is determined by the source. Now v= fλ, and because f is constant, and

v changed, λ must also change.

Sound source emits energy over time: Power of source –

Sound intensity (power passing through an area):

Intensity level (sound level):

, where I0 is the threshold of hearing, and β is in decibels.

Standing waves on a String

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Standing Waves in an Air Column

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