6.20 A machine component is loaded so that stresses at the critical location are σ 1 = 20 ksi , σ 2 = − 15 ksi , and σ 3 = 0 . The material is ductile, with yield strengths in tension and compression of 60 ksi. What is the safety factor according to (a) the maximum-normal-stress theory, (b) the maximum-shear-stress theory, and (c) the maximum-distortion-energy theory? Which theory would be expected to agree most closely with an actual test? [Partial ans.: (a) 3.0,(b) 1.71,(c) 1.97]

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

What difference(s) did you notice using a pneumatic circuit over hydraulic circuit.explain why the pneumatic piston stumbles when it hits an obstacle.

During a steady flow process, the change of energy with respect to time is zero. a)- true b)- false