For the brake shown in the figure, which one of the following

1. Self energizing for clockwise rotation of the drum
2. Self energizing for anti-clockwise rotation of the drum
3. Self energizing for rotation in either direction of the drum
4. Not of the self energizing type

Taking moment about hinge in clockwise
N_b – Fl – μNc = 0

F =	N(b - μc)
	l

Self energizing if b > μc so for clockwise rotation of drum the brake is self energizing.