a uniform plank is supported by a fixed support at A and a drum at B that rotates clockwise. the coefficients of static and kinetic friction for the two points of contact are as shown. determine wether the plank moves from the position shown if
(a) the plank is placed in position before the drum is set in motion; and
(b) the plank is first placed on the support at A and then lowered onto the drum which is already rotating. solution