Easy one...?

Question

A loundspeaker diaphragm is producing a sound for 2.3 s by moving back and forth in a simple harmonic motion. The angular frequency of the motion is 6.80 104 rad/s. How many times does the diaphragm move back and forth?
times

Answer 1

period T = 2 pi / omega

so divide the given time, t, by that period

answer = t omega / 2 pi

Answer 2

The essential piece of missing information is:

1 cycle = 2π radians

From that, you can convert rad/s to cycles/sec. That tells you how many times the diaphragm is vibrating back and forth per second.

Then you just multiply by the given time.