A particle starts from mean position and moves towards positive extreme as show below. Find the equation of the `SHM`, Amplitude of `SHM` is `A`.

Explanation

General equation of SHM can be written as x = A sin (`omega t + phi`)
At t = 0, x = 0
`:." "`0 = A sin `phi`
`:. " " phi = 0, pi " phi in [0, 2pi)`
Also, at t = 0, v = + ve
`:. " " A omega "cos" phi = + ve " "or, " "phi = 0`
Hence, if the particle is at mean position at t = 0 and is moving towards +ve extreme, then the equation of SHM is given by x = A sin `omega`t.
Similarly
for particle moving towards -ve extreme then
`phi =pi`
`:.` equation of SHM is x = A sin `(omega t+ pi )`
or x =- A sin `omega t`