Cadet Competition Written Practice Exam

In a jet engine, the excess energy is expelled out of the tailpipe as what?

1. Compression

2. Thrust

3. Lift

4. Drag

The correct answer is: Thrust

In a jet engine, the excess energy that has been harnessed through the combustion process is transformed into thrust. This energy is generated when fuel burns in the engine, producing high-pressure and high-temperature exhaust gases. These gases are expelled out of the tailpipe at high velocity, creating a reaction force in accordance with Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. This expelled mass of gas effectively propels the aircraft forward, which is the essence of thrust. Thrust is essential for overcoming the resistance (drag) and achieving the necessary airspeed for flight. Thus, the correct answer relates directly to the energy that jet engines convert for propulsion purposes and the mechanism through which an aircraft gains forward momentum.