Question

The time period of a simple pendulum, that takes 42 seconds 5. to complete 20 oscillations, equals 2.1 seconds.

Answer 1

Number of oscillations completed by the pendulum = 42

Time taken to complete 42 oscillation = 20 seconds

Time period = Number of oscillations completed/Time taken

Time period = 42/20

= 21/10 (cancelled by 2)

= 2.1

Time period = 2.1 seconds

Answer 2

$\sf \: Time_{(Period)}= \frac{ Number_{(Oscillation)}}{Time Taken}$

$\sf \: Time_{(Period)}= \frac{ 42}{20}$

$\sf \: Time_{(Period)}= \cancel \frac{ 42}{20}$

$\sf \: Time_{(Period)}= \frac{ 21}{10}$

$\sf \: Time_{(Period)}= 2.1$