An air compressor, 200 mm bore and 300 mm stroke, has a connecting rod 625 mm long. the reciprocating parts have a mass of 135 kg and the speed is 250 rev/min. when the crank is at 30° to the i. d.c and moving inwards, the pressure of the air is 840 kn/m2. the crank pin is 60 mm diameter. neglecting the effect of the mass of the connecting rod, determine: the rubbing velocity at the surface of the crank pin [0.95 m/s]the force on the crankshaft bearing [11.44 kn].the torque reaction on the frame [1.029 knm]. draw a clear sketch and explain the relevant steps.

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 the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct.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