Gaseous methane is compressed polytropically by a piston from 250C and 0.80 bar to a pressure of 5.0 bar. Assuming an index of compression of 1.2, calculate the change of entropy and work done, per unit mass of the gas. The relative molecular mass of methane is 16 and = 1.30. (

The higher the astm grain-size number, the coarser the grain is. a)-true b)-false

Inspection for bearing condition will include: (clo4) a)-color b)-smell c)-size d)-none of the above

Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 mpa and -10°c at a rate of 0.05 ka/s and leaves at 0.8 mpa and 50°c. the refrigerant is cooied in the condenser to 0.72 mpa and 26'c. it is then throttled to 0.15 mpa. sketch the t-s diagram for the system and evaluate: 6) the rate of heat removai from the refrigerated space (kw), it) the power input to the compressor (kw), ii) the isentropic efficiency of the compressor (%), and iv) the cop of the refrigerator.