Chapter 14, Problem 4STP

To determine

To Choose: The correct option. 

Answer to Problem 4STP

Option B

Explanation of Solution

Given:

Spring constant: $350\text{N/m}$

Initial stretch $1$ : $85\text{cm}$

Final stretch 2: $5\text{cm}$

Formula Used:

The following expression for work done is:

  $\begin{array}{l}W=\frac{1}{2}k{x}^2\\ W=\frac{1}{2}k\times \left(x_1{}^2-x_2{}^2\right)\end{array}$

Where,

  $W$ : Work done.

K: Spring constant.

  $x_1$ : Initial stretch

  $x_2$ : Final stretch

Calculation:

The following expression is used to calculate the work done:

  $W=\frac{1}{2}k\times \left(x_1{}^2-x_2{}^2\right)$

Putting the given values in the equation:

  $\begin{array}{l}W=\frac{1}{2}k\times \left(x_1{}^2-x_2{}^2\right)\\ W=\frac{1}{2}\times 350\times \left({0.85}^2-{0.05}^2\right)\\ W=130\text{J}\end{array}$

Conclusion:

Thus, the option B is correct.