Answer
There will be 0.407 swings per second.
Work Step by Step
(a) We can find the period of the oscillation.
$T = 2\pi~\sqrt{\frac{L}{g}}$
$T = 2\pi~\sqrt{\frac{1.50~m}{9.80~m/s^2}}$
$T = 2.46~s$
We can find the frequency of the oscillations.
$f = \frac{1}{T}$
$f = \frac{1}{2.46~s}$
$f = 0.407~Hz$
The frequency is 0.407 Hz, which means that there will be 0.407 swings per second.
