If a spring have a stiffness of 950n/m what work will be done in extending the spring by 60mm

x = 60 * 10^-3 m = 6 * 10^-2

work in = potential energy stored = (1/2) k x^2
= 950/2 (36) *10^-4
= 17100 * 10^-4 = 1.71 Joules