Which of these drum brake systems uses servo action in both directions? Select one:
O
a. Leading shoe drum brake system
b. Trailing shoe drum brake system
C. Twin leading shoe drum brake system
O
d. Duo-servo drum brake systems

An ammonia compressor has a 5% clearance volume and displacement rate of 80 l/s and pumps against a condensing temperature of 40°c. for two different temperatures of -10°c and 10°c, compute the mass flow rate of refrigerant assuming the clearance volumetric efficiency applies. discharge specific volume corresponding to-10°c and 10°c are 112.5 l/kg and 95 l/kg, respectively.