Thrust is a mechanical force most often generated through accelerating a mass of gas in the opposite direction.
Here's a breakdown of how it works:
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Newton's Third Law: Thrust fundamentally relies on Newton's Third Law of Motion: "For every action, there is an equal and opposite reaction."
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Accelerating a Mass of Gas: Engines (like those in airplanes, rockets, and jets) take a gas (usually air, or propellant in rockets) and accelerate it rearward. This acceleration is the "action."
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The Reaction - Thrust: According to Newton's Third Law, this rearward acceleration of gas generates an equal and opposite "reaction," which pushes the engine (and the vehicle it's attached to) forward. This forward push is thrust.
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Doing Work on the Gas: The engine does work on the gas to accelerate it. This work might involve:
- Jet Engines: Compressing air, mixing it with fuel, burning the mixture, and then expelling the hot exhaust gases through a nozzle.
- Rocket Engines: Burning propellant (fuel and oxidizer) and expelling the hot exhaust gases through a nozzle.
- Propeller Engines: Spinning a propeller that accelerates a large volume of air rearward.
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Nozzles Enhance Thrust: Nozzles are often used to increase the velocity of the exhaust gases. By constricting the flow, the nozzle forces the gas to accelerate, further increasing thrust.
In essence, thrust is the reaction force created when an engine expels mass (usually in the form of gas) at high speed in the opposite direction of the desired movement.
