A207 series radial-contact ball bearing is loaded uniformly (without shock) as follows: • load is 8 kn at a speed of 1440 rev/min for 25% of the time; • load is 10 kn at a speed of 720 rev/min for 50% of the time, and • load is 20 kn at a speed of 2880 rev/min for 25% of the time. estimate the bearing life for a 90% reliability.

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.