Question

A force of a magnitude 500N is applied to a Free end of a spiral spring of contant 1.0*10NM,Cal the energy stored in a streched spring

Answer 1

if you mean k = 1.0*10 N/m, then
F = kx
E = 1/2 kx^2 = 1/2 Fx

Not sure why you would specify k = 1.0*10 instead of just saying k=10. Did you leave off an exponent?

Answer 2

Yes