The engine of an airplane produces a power P a independent of speed. If the drag power is P r , then...

Question

The engine of an airplane produces a power  P a  independent of speed. If the drag power is  P r , then...

Answer

There exists a flight speed that minimises  P r .

Answer

If  P a   <   P r  for all speeds, the airplane will not be able to keep a straight and level flight and will necessarily descend.

Answer

All options are correct.

Answer

In general (disregarding stall considerations), there exist two possible flight speeds that result in straight and level flight.

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