A hydraulic brake system is shown below. The area of the piston in the master cylinder is 6.40 cm2, and the area of the piston in the brake cylinder is 1.75 cm2. The
coefficient of friction between the brake shoe and wheel drum is 0.50. What is the
frictional force between the brake shoe and wheel drum when a force of 44 N is
exerted on the pedal?

Fb, brake force, is the normal force exerted on the brake shoe

Arefrigerator uses r-134a as the working fluid and operates on the ideal vapor-compression refrigeration cycle except for the compression process. the refrigerant enters the evaporator at 120 kpa with a quality of 34 percent and leaves the compressor at 70°c. if the compressor consumes 450 w of power, determine (a) the mass flow rate of the refrigerant, (b) the condenser pressure, and (c) the cop of the refrigerator. (0.00644 kg/s, 800 kpa, 2.03)