Answer
$400\;lb$.
Work Step by Step
The given values are
$F_s=25\;lb$
$r_l=8\;in.$
$r_s=2\;in.$
Formula
$\Rightarrow \frac{F_l}{F_s}=\frac{r^2_l}{r^2_s}$
Substitute all the values.
$\Rightarrow \frac{F_l}{25\;lb}=\frac{(8\;in.)^2}{(2\;in.)^2}$
Simplify.
$\Rightarrow F_l=(25\;lb)\frac{(8\;in.)^2}{(2\;in.)^2}$
$\Rightarrow F_l=400\;lb$
Hence, the $F_l$ is $400\;lb$.
