Question

If the length of a `2 cm` spring increases to `6 cm` when a `3 kg` weight is hanging from it, what is the spring's constant?

Answer 1

`k=7.35kgs^-2`

Explanation:

Given that change in extension of spring is `deltax=4cm=4*10^-2cm`. Mass added to spring is `m=3kg`. Since this is happening on a vertical spring, `a=g`.

So, `kx=mg\impliesk=mg/(deltax)=3*9.8/4`

So simple. Answer's above.