Hi . What are the basic topics that govern Physics ( the topics a beginner to physics must be familiar with) .

Let f(x) = x4- 8x2 . find the relativeextrema of this function using the second derivative test.

What are atoms of the same element with varying number of neutrons

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.