Oxygen enters an insulated 14.2-cm-diameter pipe with a velocity of 60 m/s. at the pipe entrance, the oxygen is at 240 kpa and 20°c; and, at the exit, it is at 200 kpa and 18°c calculate the rate at which entropy is generated in the pipe.

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

To save energy, the air supply to a 2000 ft office has been shut off overnight and the room temperature has dropped to 40°f. in the morning, the thermostat is reset to 70°f and warm air at 120 f begins to flov in at 200ft'/min. the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct. the air pressure is nearly 1 atm everywhere. ignoring heat transfer with the surroundings and kinetic and potential energy effects, estimate how long it takes for the room temperature to reach 70°f. plot the room temperature as a function of time.

Amass-spring-viscous damper system of mass 3 kg has a frequency of 100 rad/s and is critically damped. its initial conditions are x(0)-3 mm and (0)-2.3 m/s. does the system overshoot its equilibrium position? prove your answer