A gas initially at 1.5 bar pressure, 0.15m

3

volume and 300 K was compressed

polytropically (pv 1.25 = constant) to 15 bar pressure. Determine the change

in entropy. Also work out the approximate entropy change obtained by

dividing the heat transferred by the mean absolute temperature during compression.

Take cp = 1.04 kJ / kg K and cv = 0.745 kJ / kg K.

Acompressor receives the shaft work to decrease the pressure of the fluid. a)- true b)- false

Aflywheel accelerates for 5 seconds at 2 rad/s2 from a speed of 20 rpm. determine the total number of revolutions of the flywheel during the period of its acceleration. a.5.65 b.8.43 c. 723 d.6.86

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