Q.
A spring 40mm long is stretched by the application of a force. If 10N force required to stretch the spring through 1mm, then work done in stretching the spring through 40mm, is
Force applied F=10N
Stretching in the spring x=1mm=0.001m ∴ spring constant k=xF=0.00110=104
Now the spring is stratched through a distance x1=40mm =0.04m
The force required to stretch it through x1 is F1=kx1 ∴ The work done by this force W=21kx12 =21×104×0.04×0.04 21×16=8J