what is phase constant

justwild

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!!!

tiny-tim

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

what is the harm if we just take [itex]\omega t[/itex] as the argument.

boneh3ad

You just shift the motion in phase slightly. All te same key features are there.

justwild

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???

tiny-tim

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
not following you