Answer to Question #181140 in Physics for Andu

Question

The aircraft, whose engine power is 3 MW, under the action of the traction force 4.5 kN flies 600 km for 0.5 hours. Determine the efficiency of aircraft engines.

Answer 1

Find the speed:

$$v=\frac dt.$$

Find power input:

$$P_i=Fv=\frac{Fd}{t}.$$

Power output:

$$P_o=3·10^6\text{ MW}.$$

Efficiency:

$$\eta=\frac{P_i}{P_o}=\frac{Fd}{P_ot}=0.5$$