Question

A pendulum oscillates 80 times in 4 sec .Find its time period and frequency​

Answer 1

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no of oscillation in 4 secs=80

no of oscillations in one second=80/4=20

frequency is 20Hz

time period = 1/Frequency

                 =1/20=(1*5)/(20*5)=5/100=0.05

time period= 0.05secs

frequency= 20Hz

Answer 2

Given: Time (t)=4sec,

Oscillation=80 times,

To find: Time period (T) and Frequency (f);

Solution:

The number of oscillations in 4 seconds is 80,

So, the number of oscillations in 1 sec will be,

4 seconds = 80 oscillations,

1 second = $\frac{80}{4}$ oscillations,

1 second=20 oscillations,

As we know the number of oscillations in one second is called frequency.

So, frequency = 20Hz,

Time period = $\frac{1}{frequency}$,

Time period=$\frac{1}{20}$,

Time period=0.05seconds,

Therefore, time period(T) =0.05sec and frequency(f) ​=20Hz.