Question

A long spring is stretched by 2 cm, its potential energy is U. If the spring is stretched by 10 cm, the potential energy stored in it will be

• A.
• B.
• C.
• D.

Answer 1

The correct option is D

Elastic potential energy of a spring $U=\frac{1}{2}k{x}^2\therefore U\infty x^2$

So $\frac{U_2}{U_1}={\left(\frac{x_2}{x_1}\right)}^2\Rightarrow \frac{U_2}{U}={\left(\frac{10cm}{2cm}\right)}^2\Rightarrow U_2=25U$