The simple band brake is constructed so that the ends of the friction strap are connected...

The simple band brake is constructed so that the ends of the friction strap are connected to the pin at A and the lever arm at B. If the wheel is subjected to a torque of M = 80 lb • ft, and the minimum force P = 20 lb is needed to apply to the lever to hold the wheel stationary, determine the coefficient of static friction between the wheel and the band.