What is the phase difference between the displacement and velocity displacement and acceleration of a particle performing SHM starting from extreme position?

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Consider a particle performing S.H.M., with amplitude A and period T = 2π/ω starting from the mean position towards the positive extreme position where w is the angular frequency. Its displacement from the mean position (x), velocity (v), and acceleration (a) at any instant are

x = A sin  ωt = A sin `((2π)/"T""t")` .........`(∴ ω = (2π)/"T")`

v = `"dv"/"dt"` = ωA cos ωt = ωA cos `((2π)/"T""t")`

a = − ω2A sin  ωt = − ω2A sin `((2π)/"T""t")`

as the initial phase x = 0.

Using these expressions, the values of x, v, and a at the end of every quarter of a period, starting from t = 0, are tabulated below.

t 0 `"T"/4` `"T"/2` `"3T"/4` T
ωt 0 `π/2` π `"3π"/2`
x 0 A 0 −A 0
v ωA 0 −ωA 0 ωA
a 0 −ω2A 0 ω2A 0

Using the values in the table we can plot graphs of displacement, velocity, and acceleration with time

What is the phase difference between the displacement and velocity displacement and acceleration of a particle performing SHM starting from extreme position?

Graphs of displacement, velocity, and acceleration with time for a particle in SHM starting from the mean position

Conclusions:

  • Displacement, velocity and acceleration of S.H.M. are periodic functions of time.
  • Displacement time curve and acceleration time curves are sine curves and velocity time curve is a cosine curve.
  • There is a phase difference of `π/2` radian between displacement and velocity.
  • There is a phase difference of `π/2` radian between velocity and acceleration.
  • There is a phase difference of π radian between displacement and acceleration.