The Sears Tower vibrates back and forth, it makes about 8.6

vibrations in 60 seconds. Determine the frequency and the

period of vibration of the Sears Tower.

Answer: Frequency is 0.143 Hz; Period is 7 seconds

Explanation:

Number of vibrations = 8.6

Time required = 60 seconds

Period (T) = ?

Frequency of the vibrations (F) = ?

A) Recall that frequency is the number of vibrations that the Sears tower completes in one second.

i. e Frequency = (Number of vibrations / time taken)

F = 8.6/60 = 0.143Hz

B) Period, T is inversely proportional to frequency. i. e Period = 1/Frequency

T = 1/0.143Hz

T = 7 seconds

Thus, the frequency and period of the vibrations of the Sears Tower are 0.143 Hz

and 7 seconds respectively.