A piston-cylinder contains 5 kg of an ideal gas (cv = 0.7 kJ/kg∙K, R = 0.3 kJ/kg∙K) at 100 kPa and 327ºC. The gas is cooled at constant pressure until it loses 1000 kJ of heat. Determine the entropy change of the gas, in kJ/K, and the required temperature of the surroundings in order to assure that there is not a violation of the second law of thermodynamics?

An important dimensionless parameter concerned with very high-speed flow is the mach number, defined as v/c, where v is the speed of the object such as an airplane or projectile, and c is the speed of sound in the fluid surrounding the object. for a projectile traveling at 1170 mph through air at 50 ˚f and standard atmospheric pressure, what is the value of the mach number?