Find the natural frequency of the system shown in the f
![Find the natural frequency of the system shown in the f](https://static.tllms.com/ckeditor_assets/pictures/8701/content_6_56.jpg)
| Find the natural frequency of the system shown in the figure. The pulleys are smooth, massless and the spring is unstretched in the equilibrium position.
![](https://static.tllms.com/ckeditor_assets/pictures/8701/content_6_56.jpg)
![](https://static.tllms.com/ckeditor_assets/pictures/8701/content_6_56.jpg)
A. π√mk
B. 2π√mk
C. π√2mk
D. π√3mk
Please scroll down to see the correct answer and solution guide.
Right Answer is: A
SOLUTION
Let x be the displacement of the block from the equilibrium position.
Since the length of the string remains the same, the spring extends by x = (2x).
The energy of the system is
E=12kx2+12mv2=12k(2x)2+12mv2
Differentiate with respect to time
dEdt−4kxdxdt+mvdvdt=0 (energy conservation)
⇒4kxv+mvd2xdt2=0
∴4kg+md2xdt2=0⇒d2xdt2+4kxm=0
∴T=2π√m4k=π√mk