What are features of an isentropic process? . derive expression describing variation in pressure with specific volume for such a process occurring in the ideal gas. assume that specific heats (at constant pressure and constant volume) are not varying \n temperature. what real processes can be modelled with use of the isentropic process?

Asolid cylinder is concentric with a straight pipe. the cylinder is 0.5 m long and has an outside diameter of 8 cm. the pipe has an inside diameter of 8.5 cm. the annulus between the cylinder ad the pipe contains stationary oil. the oil has a specific gravity of 0.92 and a kinematic viscosity of 5.57 x 10-4 m2/s. most nearly, what is the force needed to move the cylinder along the pipe at a constant velocity of 1 m/s?