Question

$U$ is the $PE$ of an oscillating particle and $F$ is the force acting on it at a given instant. Which of the following is true ?

• A. $\frac{U}{F} + x = 0$
• B. $\frac{2U}{F} + x = 0$
• C. $\frac{F}{U} + x = 0$
• D. $\frac{F}{2U} + x = 0$

Answer 1

Answer: (B)

$\frac{2U}{F} + x = 0$

Answer 2

The potential energy, $U=\frac{1}{2} k x^{2}$
$2 U=k x^{2}$
$2 U=-F x \,\,\,\,[\because F=-k x]$
or $\,\,\ \frac{2 U}{F} =-x$
or $\,\,\,\frac{2 U}{F}+x =0$