What Is Retropulsion?

If a stationary object is split into two parts under the action of an internal force, one part moves in one direction, and the other part must move in the opposite direction. This phenomenon is called recoil. In the recoil movement, the recoil effect on the object is usually called recoil force. This process follows the law of conservation of momentum.

When a person jumps from the boat to the shore, the boat will leave the shore and retreat. This reverse movement of the boat is the recoil movement. The recoil movement is very common. The boat is parked by the lake. When a person walks forward on the boat and intends to go ashore, the boat moves backward and leaves the shore. If a person turns around and walks back to the place, the boat Moved to the shore again. This is a manifestation of momentum conservation. The original total momentum of the ship and the person is zero (still at the shore): When the person moves forward, the person gets the forward momentum. Since the interaction force between the person and the ship at this time is the static friction, it is the internal force of the human-ship system Therefore, the momentum of this system is conserved, and the total momentum is still zero. The ship must also get backward momentum at the same time: when people move backward, the ship moves forward, and the sum of the two momentums is still zero (the water resistance is ignored) Excluding) ^[1]

There are similarities between recoil motion and collision and explosion.

System in

Jet planes and rockets use the principle of recoil, and they both rely on the recoil of jets to obtain huge speeds. Modern jet aircraft can continuously fly backwards at a speed of more than 1000m / s. The fuel enters the combustion chamber. In the combustion chamber, high-voltage electric ignition and fuel injection combustion, because the gas contains oxygen, the gas expands and explodes backward. The turbine is behind the combustion chamber, and a turbine disk is mounted on the turbine shaft. Filled with blades, the turbine is divided into 7 to 13 stages, and the turbine is rotated one stage and one stage backward, and the gas is compressed by one stage of the turbine at the rear of the engine, and the pressure is increased several hundred times. Finally. It sprays out at a high speed through the tail nozzle, which generates a reaction force and makes the aircraft fly forward ^[3] .