$(10$ points$)$ The $100$ lb block is initially at rest on the incline when the force $P=18lb$ is applied as shown, and the coefficients of friction between the block and the incline are ${}_s=0\mathrm{.}2$ and ${}_k=0\mathrm{.}15.$ Determine the magnitude and direction of the friction force on the block.

$F=$ lb$,$ up$/$down incline $($circle one$)$ Plz help