$)(2\mathrm{.}5$ pts$)$ A worker pushes a $35\mathrm{.}0-$kg crate up a $5\mathrm{.}0-$meter$-$long inclined plane that makes

a $25$ angle with the horizontal. The worker applies a horizontal force of $180$ N$,$ and the

crate moves at constant speed. Find:

$($a$)$ The work done by the $180-$N force, and

$($b$)$ The coefficient of kinetic friction between the crate and the inclined plane