Question

If the force constant of a wire is $k$, the work done in increasing the length $L$ of the wire by $l$ is

• A. 3Kl
• B. 2Kl
• C.
• D.

Answer 1

The correct option is C

Comparing $F=\frac{YA}{L}l$ with $F=kl$ we have $k=\frac{YA}{L}$, which is the spring constant of the wire.

Since we are comparing with a spring, the energy stored is $U=\frac{1}{2}k{l}^2$