Legend says that archimedes, in determining whether or not the king’s crown was made of pure gold, measured its volume by the water displacement method. if the crown weighs 600 gm in air, what would its "weight be in water", necessary to prove that it is pure gold?

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.