Question
A particle of mass $$1\,kg$$ is placed in a potential field. Its potential energy is given by $$U = 10{x^2} + 5.$$ The frequency of oscillations of the particle is given by
A.
$$\left( {\sqrt {10} } \right)$$
B.
$$\left( {\sqrt {5} } \right)$$
C.
$$\left( {\sqrt {\frac{{10}}{\pi }} } \right)$$
D.
$$\left( {\frac{{\sqrt 5 }}{\pi }} \right)$$
Answer :
$$\left( {\frac{{\sqrt 5 }}{\pi }} \right)$$
Solution :
$$\eqalign{
& F = - \frac{{dU}}{{dx}} = - 20\,x \cr
& a = \frac{F}{M} = \frac{{ - 20\,x}}{1} = - 20\,x \cr
& - 20\,x = - {\omega ^2}\left( x \right) \cr
& \therefore \omega = \sqrt {20} = 2\sqrt 5 \cr
& f = \frac{\omega }{{2\pi }} = \frac{{2\sqrt 5 }}{{2\pi }} = \left( {\frac{{\sqrt 5 }}{\pi }} \right) \cr} $$