Air in a piston-cylinder assembly undergoes a process from state 1, where t1= 300 k, p1= 100 kpa, to state 2 where t2=500 k, p2=650 kpa. using the ideal gas model for air, determine the change in specific entropy between these states, in kj/kg*k, if the process occurs

a) without irreversibilities

b) with irreversibilities

Ariver flows from north to south at 8 km/h. a boat is to cross this river from west to east at a speed of 20 km/h (speed of the boat with respect to the earth/ground). at what angle (in degrees) must the boat be pointed upstream such that it will proceed directly across the river (hint: find the speed of the boat with respect to water/river)? a 288 b. 21.8 c. 326 d. 30.2

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented

Slip occurs via two partial dislocations because of (a) the shorter path of the partial dislocation lines; (b) the lower energy state through partial dislocations; (c) the charge balance.