An ideal brayton refrigeration cycle has a compressor pressure ratio of 7. at the compressor inlet, the pressure and temperature of the entering air are 22 lbf/in2 and 450ºr, respectively. the temperature at the inlet of the turbine is 680ºr. for a refrigerating capacity of 13.5 tons, determine
(a) the mass flow rate of the refrigerant, in lb/min.
(b) the net power input, in btu/min
(c) the coefficient of performance.

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me