what is phase constant


by justwild
Tags: constant, phase
justwild
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#1
Feb10-12, 11:31 PM
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I just started learning Simple Harmonic Motion and encountered a word Phase Constant [itex]\phi[/itex] .
Actually it appeared as
f(t)=rsin([itex]\omega t+\phi[/itex])
I am confused whether phase constant is actually the initial position of the particle(which execute SHM) and therefore the point on graph at time=0 or not!!!
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tiny-tim
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#2
Feb11-12, 04:16 AM
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hi justwild! welcome to pf!

you're right, the phase constant is the initial angle (or initial phase): the angle (or phase) at t = 0
justwild
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#3
Feb11-12, 11:12 AM
P: 51
what is the harm if we just take [itex]\omega t[/itex] as the argument.

boneh3ad
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Feb11-12, 11:23 AM
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what is phase constant


You just shift the motion in phase slightly. All te same key features are there.
justwild
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#5
Feb11-12, 11:30 AM
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If [itex]\phi[/itex] is the initial angle then I think the sinusoidal graph will show different starting points(t=0) for different values of [itex]\phi[/itex] of the same amplitude and frequency of vibration. Is that so???
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Feb11-12, 12:53 PM
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Quote Quote by justwild View Post
what is the harm if we just take [itex]\omega t[/itex] as the argument.
you can eliminate the phase constant by changing the starting time

if you replace t by t + φ/ω, then the phase constant is zero
Quote Quote by justwild View Post
If [itex]\phi[/itex] is the initial angle then I think the sinusoidal graph will show different starting points(t=0) for different values of [itex]\phi[/itex] of the same amplitude and frequency of vibration. Is that so???
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