Question

When its 115-kW (154.1-hp) engine is generating full power, a small single-engine airplane with mass 685 kg gains altitude at a rate of 3.0 m/s (180 m/min, or 590.4 ft/min). What fraction of the engine power is being used to make the airplane climb? (The remainder is used to overcome the effects of air resistance and of inefficiencies in the propeller and engine.)

Answer 1

Power = F.v

F = mg = 685g

Power = 685 x 9.8 x 3 =20139 W = 20.14 kW

fraction of power used = 20.14 / 115 = 0.175