2.A plank is tilted slowly to an angle of 30 degrees with a 12 pound block on it
Find FN, FF and the static friction?
The normal force is Fn = 12 lb * cos 30
The friction force is Ff = Fn sin 30 if the object is not moving. If the object starts moving at that tilt angle, the coefficient of static friction is
Mus = Ff/Fn tan 30