The force $P$ is applied to the $66-kg$ block when it is at rest. Determine the magnitude and direction of the friction force exerted by the surface on the block if $($a$)P=0,(b)P=289N,$ and $($c$)P=460N.($d$)$ What value of $P$ is required to initiate motion up the incline? The static and kinetic coefficients of friction between the block and the incline are ${}_s=0\mathrm{.}33$ and ${}_k=0\mathrm{.}27,$ respectively. The friction force is positive if up the incline, negative if down the incline.

a$)$ F$=\_\_\_$N

b$)$ F $=\_\_\_$N

c$)$ F $=\_\_\_$N

d$)$ P$=\_\_\_$N