Question

A particle executes simple harmonic motion with a frequency $f$. The frequency with which its kinetic energy oscillates is

• A. $f/2$
• B. $f$
• C. $2f$
• D. $4f$

Answer 1

Answer: (C)

$2f$

Answer 2

Kinetic energy $K = \frac{1}{2}mv^{2} = \frac{1}{2}ma^{2}\omega^{2}\cos^{2}\omega t$ $= \frac{1}{2}m\omega^{2}a^{2}(1 + \cos 2\omega t)$ hence kinetic energy varies periodically with double the frequency of S.H.M. i.e. $2\omega$.