Answer:[tex]W=\frac{3}{4} ft-lb[/tex]
Explanation:
Given
Work required to stretch 1 ft is 12 ft-lb
and we have to find work required to stretch 3 in.
i.e. [tex]\frac{1}{4} ft[/tex]
[tex]12=\frac{1}{2}K\left ( 1\right )^2 ------(1)[/tex]
[tex]W=\frac{1}{2}k\left ( \frac{1}{4}\right )^2-----(2)[/tex]
divide (1)&(2)
[tex]\frac{12}{W}=\left ( \frac{4}{1}\right )^2[/tex]
[tex]W=\frac{12}{4\times 4}[/tex]
[tex]W=\frac{3}{4} ft-lb[/tex]
