Which sentence best describes a refrigerator? A.
It extracts heat from a high-temperature system and loses the heat to a low-temperature system.
B.
It extracts heat from a high-temperature system, loses some of the heat to a low-temperature system, and does work at its output.
C.
It extracts heat from a low-temperature system using work at its input, and rejects heat to a high-temperature system.
D.
It extracts heat from a low-temperature system and retains all the heat.

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

During a steady flow process, the change of energy with respect to time is zero. a)- true b)- false

Asimple rankine cycle uses water as the working fluid. the water enters the turbine at 10 mpa and 480c while the condenser operates at 6 kpa. if the turbine has an isentropic efficiency of 80 percent while the pump has an isentropic efficiency of 70 percent determine the thermal efficiency