A spring is stretched by a 40mm by a force of 10 newton.what is the work done by the force

Answer 1

10 N = k * 0.040 meters
so
k = 10/.04 =1 Newton / .004 meter

Work done = potential energy gained = (1/2) k x^2
= (1/2)(1/.004)(.04)(.04) Joules