Question

A pendulum takes 60 seconds to swing through 2 complete cycles.

A. How long does it take to complete one cycle?
B. What is its period?
C. What is its frequency?

Answer 1

A : 30 seconds
B: T = 2π Square root of√L/g,
C: how many back-and-forth swings there are in a second, measured in hertz. f = [√(4.9)]/6.28 = 2.21/6.28 = 0.353 Hz.

Answer 2

A. If nobody is messing with the pendulum, it's doing one complete cycle every 30 seconds.

B. That's exactly what "period" means, so A. and B. are the same number ... 30 seconds.

C. Frequency = 1/period.
1/30s = 0.0333.../s.
That's 0.0333... Hz.