A jet engine on a test bed takes in 20.0kg of air per second at 100ms-1 and burns 0.8kg of fuel per second. After compression and heating the exhaust gases are ejected at 500ms-1 relative to the aircraft. Calculate the thrust of the engine.
- 天同Lv 71 decade agoFavorite Answer
Change of momentum of the air in 1 second
= 20 x (500-100) Ns = 8000 Ns
Change of momentum of the fuel in 1 second
= 0.8 x 500 Ns = 400 Ns
hence, total change of momentum = (8000 + 400) Ns = 8400 Ns
Thrust = rate of change of momentum = 8400/1 N = 8400 N