A vapor compression heat pump cycle requires that the evaporator and condenser operate within 10°C of their respective heat reservoirs. The cycle employs R134a as the working fluid, which exits the evaporator as a saturated vapor and exits the condenser as a saturated liquid. The compressor operates with an isentropic efficiency of 82%. If the desired inside temperature is 21 °C and the outside temperature is 0 °C, determine:

Aquick transition of the operating speed of a shaft from its critical speed will whirl amplitude. (a) increase (b) limit (c) not affect (d) zero

What are the major differences between injection molding and extrusion?

To save energy, the air supply to a 2000 ft office has been shut off overnight and the room temperature has dropped to 40°f. in the morning, the thermostat is reset to 70°f and warm air at 120 f begins to flov in at 200ft'/min. the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct. the air pressure is nearly 1 atm everywhere. ignoring heat transfer with the surroundings and kinetic and potential energy effects, estimate how long it takes for the room temperature to reach 70°f. plot the room temperature as a function of time.