Question

It requires 49 J of work to stretch an ideal very light spring from a length of 1.8 m to a length of 3.5 m. What is the value of the spring constant of this spring?

Answer 1

\[\huge E_{\text{spring}}=\frac{ 1 }{ 2 }k(\Delta x)^2\]
:)

Answer 2

\(\Delta x\) is the elongation/compression of the spring. I normally prefer to call it \(\Delta l\), but most use \(x\)