A lever of negligible weight is loosely fitted onto a 30-mm-radius fixed shaft as shown. K...

A lever of negligible weight is loosely fitted onto a 30-mm-radius fixed shaft as shown. Knowing that a force P of magnitude 275 N will just start the lever rotating clockwise, determine (a) the coefficient of static friction between the shaft and the lever, (b)the smallest force P for which the lever does not start rotating counterclockwise.