If the cutting force of an orthogonal cutting operation is 600N and the thrust force is 325 N with the following additional conditions; rake angle = 5°, depth of cut = 0.4 mm, width of cut = 6 mm, chip thickness = 0.6 mm, velocity of cutting = 3.25 m/s, friction angle of 10°. What would be the total specific energy for the system?

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 the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct.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.