Two piano strings are supposed to be vibrating at 220 Hz , but a piano tuner hears three beats every 3.2 s when they are played together. f one is vibrating at 220 Hz , what must be the frequency of the other (is there only one answer)

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)