Question

A vibrating object if the ratio between its periodic time and its frequency 1/400 Sec² then the number of complete vibrations done in 20 seconds isA-20B-120C-200D-40p

Answer 1

Given data:

* The ratio between its periodic time and its frequency is,

$\frac{T}{f}=\frac{1}{400}s^2$

Solution:

Let the object make n vibrations in t seconds.

Then, the frequency is written in terms of time period is,

$f=nt$

From the given relation, the frequency per unit time is,

$\begin{gathered} \frac{f}{T}=400^{} \\ f=400^{} \end{gathered}$

Thus, in time 20 seconds, the number of vibrations of the given object is,

$\begin{gathered} nt=400 \\ n\times20=400 \\ n=\frac{400}{20} \\ n=20\text{ } \end{gathered}$