Aboy yells in a narrow valley. the sound reflects off of a boulder that is 80m away. how long will it take to hear the echo if the speed of a sound wave is 320 m/s

Nitrogen (n2) undergoes an internally reversible process from 6 bar, 247°c during which pν1.2 = constant. the initial volume is 0.1 m3 and the work for the process is 121.14 kj. assuming ideal gas behavior, and neglecting kinetic and potential energy effects, determine heat transfer, in kj, and the entropy change, in kj/s. show the process on a t-s diagram.