Redo Problem 7.6 using Vesic’s (1975) solution [Eq. (7.12)]. 7.8 A 2 m wide continuous foundation is placed at 1 m depth within a 1.5 m thick sand layer that is underlain by a weaker clay layer. The soil properties are as follows: Upper sand layer: unit weight 5 18.0 kN/m3 , f9 5 388 Lower clay layer: unit weight 5 19.0 kN/m3 , undrained shear strength 5 25 kN/m2 Determine the maximum wall load that can be allowed on the foundation with FS 5 3.

An ideal otto cycle with air as the working fluid has a compression ratio of 8. the minimum and maximum temperatures in the cycle are 300 k and 1340 k. use constant specific heats at room temperature to determine (a) the amount of heat transferred to the air during the heat- addition kj/kg, (b) the thermal efficiency, and (c) the thermal efficiency of a carnot cycle ope limits. process, in rating between the same temperature

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

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.