Question

A pendulum makes 40 vibrations in 20 seconds. calculate it's period?

Answer 1

The frequency is (40) / (20 seconds) = 2 per second = 2 Hz.

The period is 1/(frequency) = 1 / (2 per second) = 1/2 second .

Answer 2

Answer : Time period will be 0.5 seconds.

Explanation : We can use the formula as;

f = c / λ

f = wave speed c (units m/s) / wavelength λ (units m).

Here, c = 40 and λ = 20;

f = 40 / 20 = 2 Hz

The formula for finding time period is:

`T (period) = (1)/(f)` where f = frequency

We have, f = 2 Hz;

`T (period)= (1)/(2)` = 0.5 second.

Therefore, time period will be 0.5 seconds.