(a) Given,
40 oscillations in one minute, so
frequency per second = 40/60
= 2/3
= 0.67 Hz
Hence, the frequency of oscillation = 0.67 Hz
(b) As we know that,
T = 1/f
So, substituting the value of f = 0.67 s-1, in equation above we get,
T = 1/0.67 = 1.49253s ≈ 1.5 s
Hence, time period of the simple pendulum is 1.5 s.