Question

Initially the system is at rest and spring in natural length. Now, the block is pushed towards left and released. Then, after release until the spring reaches back to its natural length:

• A. work done by spring on wall is $+\frac{1}{2}k{x}^2$
• B. work done by spring on block is $-\frac{1}{2}k{x}^2$
• C. work done by spring on wall is zero
• D. work done by spring on wall is $\frac{1}{2}k{x}^2$ higher than work done by spring on block.

Answer 1

The correct option is C work done by spring on wall is zero

$W=F.dcos\theta =F\left(0\right)cos0=0$
Work done by spring on wall is zero since the displacement due to the spring force is zero.