Question

A particle in SHM starts its journey (at `t = 0`) from `x = - (A)/(2)` in negetive direction. Write `x - t` eqution corresponding to given condition. Angular freqency of oscillations is `omega`.

Answer 1

Correct Answer - A
For the given initial conditions, partical `Q` on reference circle is as shown in figure. This is `210^(@)` ahead or `150^(@)` behind the sine line or `120^(@)` ahead or `240^(@)` behind the cosine line. Therefore, the `x - t` equation can be written as
`x = Asin(omega t + 210^(@)) = A sin (omega t - 150^(@)) = A cos(omega t + 120^(@)) = A cos (omega t - 240^(@))`