(95 A book has a weight of 2N and is at rest on a table. The table exerts a normal reaction force of 2N upwards on the book. Explain why these two forces are not an example of Newton's third law.

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.