What causes thrust of an engine?

Change in momentum

Difference in lift distribution

Difference in drag distribution

Mass flow entering the engine

Correct Answer : Change in momentum

Explanation : The thrust is caused due to the difference in momentum of the air which leaves from the exhaust and the one that enters the engine. There is a presence of pressure difference between exhaust and the inlet which causes thrust.

Recently Updated in Aerodynamics Questions

What is the thrust of an engine if the inlet and exhaust mass flow rate are 150 kg/s and 190 kg/s respectively with the pressure difference between the exhaust and ambient air is 1.85 × 10⁴? The exhaust area is 2m², the ambient and exhaust velocities are 280 m/s and 400 m/s.

50 kN

62 kN

71 kN

84 kN

Correct Answer : Option (C) : 71 kN

Explaination : Aerodynamics

The integral form of the conservative equation is used for computing thrust of an engine.

True

False

Can Not Say

None of the above

Correct Answer : Option (A) : True

Explanation : The integral form of conservative equation finds use in many practical scenarios such as finding thrust of a jet propulsion device – engine. It can be used to find out the thrust of turbojet, turboprop, ramjet, turbofan, rocket engine and many more.

Integral form of momentum equation cannot replace the need for theoretical and experimental measurements.

True

False

Can Not Say

None of the above

Correct Answer : Option (B) : False

Explanation : In real life scenario, computing the thrust of the jet engine using theoretical and experimental results can be very exhaustive. The data obtained is not just extensive but also complex. Thus, to replace this, an integral form of momentum equation is used which gives the result much more accurately.