4. The blades on a fan have a frequency of 15 Hz.

a) How many cycles do the blades complete in five minutes?

b) What is the period for the fan blades?

c) How long would it take for the fan blades to complete 100 revolutions?

a) 4500 cycles b) 0.0667s c) 6.67s

Explanation:

a) 15 Hz = 15 cycles / s

5 mins = 300s

15 cycles/s * 300s = 4500 cycles

b) Period = 1 / frequency

Period = 1 / 15 cycles/s

Period = 0.0667s

c) Period * number of revolutions = time

0.0667 * 100 = 6.67s