Question

A jet aircraft is traveling at 262 m/s in hor-

izontal flight. The engine takes in air at a

rate of 85.9 kg/s and burns fuel at a rate of

3.92 kg/s. The exhaust gases are ejected at

921 m/s relative to the aircraft.

Find the thrust of the jet engine.

Answer 1

Speed of the air craft,
`$S_a$` = 262 m/s

Fuel burns at the rate of,
`$S_b$` = 3.92 kg/s

Rate at which the engine takes in air,
`$S_(air)$` = 85.9 kg/s

Speed of the exhaust gas that are ejected relative to the aircraft,
`$S_(exh)$` =921 m/s

Therefore, the upward thrust of the jet engine is given by

`$F=S_(air)(S_(exh)-S_a)+(S_b * S_(exh))$`

F = 85.9(921 - 262) + (3.92 x 921)

= 4862635.79 + 3610.32

=
`$4.8 * 10^6 \ N$`

Therefore thrust of the jet engine is
`$4.8 * 10^6 \ N$`.