(a) Find its spring constant.

(b) The load and the spring are taken down. Two people pull in opposite directions on the ends of the spring, each with a force of 150 N. Find the length of the spring in this situation.

I found out (a) is 2.24 kN/m but I don't know how to get to the answer.

So far I've just converted all the units, so 37 cm to .37 m and 40.5 cm to .405 m.

And I guess y would be .405-.37= .035 m