Pressure Decrease (Isentropic Process) During a reversible adiabatic process of 1 lbm of an ideal gas in a piston-cylinder, the pressure decreases from 196.8 psi to 15.8 psi. The gas constant is 37.7 ft. lb/lbm. oR and the initial temperature of the gas is 863 oF. Determine
a) the initial and final gas density in [Ibm/ft'].
b) the total work produced in [ft. lb].
c) the total change in internal energy in [Btu].
Assume that the specific heat at constant pressure is cp 0.22 Btu/lbm.
pi = 0.568 Ibm/ft3
W = -75,210 ft. lb
AU = -96.3
p2 = 0.080 lbm/ft3

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.

The y form of iron is known as: a) ferrite b) cementite c) perlite d) austenite

The higher the astm grain-size number, the coarser the grain is. a)-true b)-false