Asteel with a yield stress of 300 mpa is tested under a state of stress where σ2 = σ1/2 and σ3 = 0. what is the stress at which yielding occurs if it is assumed that:

(a) the maximum-normal-stress criterion holds?

(b) the maximum-shear-stress criterion holds?

(c) the distortion-energy criterion holds?

Air inially occupying a volume of 1 m2 at 100 kpa, 27 c undergoes three internally reversible processes in series. process 1-2 compression to 500 kpa during which pv constant process 2-3 adiabatic expanslon to 100 kpa process 3-1: constant-pressure expansion to 100 kpa (a) calculate the change of entropy for each of the three processes. (b) calculate the heat and work involved in each process. (c) is this cycle a power cycle or refrigeration cycle?