Final answer:
Thrust in a gas turbine engine is generated by the reaction force created by expelling exhaust gases at high velocity out of the engine, according to Newton's third law. This forward force propels the engine and aircraft forward.
Step-by-step explanation:
Referencing a gas turbine engine, thrust results from the reaction force called thrust, which occurs as a result of Newton's third law of motion. For every action, there is an equal and opposite reaction. In the context of a gas turbine engine, this pertains to the force that discharges the exhaust gases from the rear of the engine, producing a force that pushes the engine forward. This principle is similar to that of a rocket, where the backward expulsion of gas creates a significant forward reaction force. Unlike rockets, which are able to function more efficiently in a vacuum, the gas turbine engine works within the atmosphere to produce thrust.
In jet engines and other types of turbine engines, the process involves drawing in air, compressing it, mixing it with fuel, igniting the mixture to produce high-pressure exhaust gases, and then expelling these gases out through a nozzle to generate thrust. The force generated propels the engine, and thus the aircraft, forward. It is important to note that thrust is generated by the high velocity of the exhaust gases leaving the engine, not by 'pushing' against the air or ground.