A certain metal wire has a cross sectional area of 1 mm2 and is 1 m long. when it is hung from the ceiling and a 10 kg mass is hung from the bottom of it, the wire stretches 1 mm. treat the wire as a single macroscopic spring. what is its effective spring constant?

From the Hooke's law, the extension force of an elastic material is directly proportional to the extension.

That is, F = k e, where F is the force, k is the constant and e is the extension

F = 10 * 10 = 100 N

e = 1mm or 0.001 m

Hence, k = F/e

= 100 N / 0.001

= 100000 N/m or 100 N/mm