question_answer 26)

                The displacement of a particle is represented by the equation \[y=3\,\cos \left( \frac{\pi }{4}\,-\,2\omega t \right)\]                 The motion of the particle is                 (a) simple harmonic with period \[2\pi /\omega \]                 (b) simple harmonic with period \[\pi /\omega \]                 (c) periodic but not simple harmonic.                 (d) non-periodic.

Answer:

                (b) Compare with \[y=a\cos \,(\omega t-\phi )\]