# what is phase constant

by justwild
Tags: constant, phase
 P: 51 I just started learning Simple Harmonic Motion and encountered a word Phase Constant $\phi$ . Actually it appeared as f(t)=rsin($\omega t+\phi$) 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!!!
 Sci Advisor HW Helper Thanks PF Gold P: 26,109 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
 P: 51 what is the harm if we just take $\omega t$ as the argument.
P: 1,408

## what is phase constant

You just shift the motion in phase slightly. All te same key features are there.
 P: 51 If $\phi$ is the initial angle then I think the sinusoidal graph will show different starting points(t=0) for different values of $\phi$ of the same amplitude and frequency of vibration. Is that so???
HW Helper
Thanks
PF Gold
P: 26,109
 Quote by justwild what is the harm if we just take $\omega t$ 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 by justwild If $\phi$ is the initial angle then I think the sinusoidal graph will show different starting points(t=0) for different values of $\phi$ of the same amplitude and frequency of vibration. Is that so???
not following you

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