The horizontal force P is applied to the cable wrapped around the inner spindle of the spool. The spool of cable weighs 20.37 lb/ft2, per unit of cross-sectional area that is visible, which accounts for the width into the page. The static friction between the spool and the 15° incline is ms = 0.40. Determine the friction force acting on the spool if P is just sufficient to roll the spool up the incline without sliding.

( 18" 30" 15