Answer
70.7 minutes
Work Step by Step
We first must find the period of an oscillation:
$ T = 2\pi \sqrt{\frac{2L}{3g}}= 2\pi \sqrt{\frac{2(.188)}{3(9.81)}}=.710\ s$
We multiply this by the number of oscillations to find:
$t = .710\ s \times 5974 = 4242.72 \ s = \fbox{70.7 minutes}$
