Question

If the length of a `23 cm` spring increases to `40 cm` when a `7 kg` weight is hanging from it, what is the spring's constant?

Answer 1

`k = 4035.29` kg/s^2

Explanation:

Hooke's Law: `F = -kx`

`F = mg` ; `m = 7` kg and `g = 9.8` N
`k = ?`
`x = 40 - 23 = 17` cm `= 0.17`m

The negative sign is simply for directionality. We only care about magnitude here.

`k = (mg)/(x) =((7)(9.8))/(0.17) = 4035.29` kg/s^2