Q55
General SciencePhysics
The frequency of a simple pendulum is f. What is the frequency change in the energy of the pendulum?
- a.$\frac{f}{2}$
- b.f
- c.2f
- d.4f
Answer: (C) 2f
Kinetic energy depends on $v^2$, and $\sin^2\omega t = \frac{1 - \cos 2\omega t}{2}$, so the kinetic and potential energies oscillate at twice the pendulum's frequency, 2f. Kinetic energy peaks twice per oscillation (once each way through the mean position), so f or f/2 is wrong.