Introduction+to+Rocket+Physics

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Introduction to Rocket Physics The origin of the rocket is traced back to China in the 1200s. Initially described as “arrows of flying fire,” rockets were used by Chinese armies in A.D. 1232. The use of rockets soon spread throughout much of Asia and Europe for military use and fireworks displays. Today, the invention of the rocket has propelled one of the most adventurous endeavors man has have undertaken, the exploration of space. The rocket has also been used for military use, atmospheric research, launching probes and satellites, and fireworks displays. Whether one is launching a model rocket or a space shuttle, the same physics concepts are applied.


 * How Do Rocket Engines Work?**

The engine, the heart of the rocket, is composed of various parts that initiate the lift off, coasting, and ejection of the recovery system. The thrust is a force that drives the rocket forward through the air. Rocket engines generate thrust by expelling gas produced by the burning of the propellants: a mixture of fuel and an oxidizer. At room temperature the engine propellant does not burn; however, when heat is added through the use of an electrically controlled igniter, the engine begins to combust. The exhaust (or gaseous mass produced from burning) is propelled out of the engine through the engine’s clay nozzle. As opposed to a jet engine, a rocket engine does not draw in oxygen from the surrounding air. Newton’s Third Law of Motion forms the basis for the acceleration of the rocket: //for every action there is an equal// //and opposite reaction//. The expulsion of the gas through the clay nozzle of the engine (the “action”—//downward//) results in the acceleration of the rocket //upward// (the “reaction”). Please see Figure 1 to the right.

When the propellant is expended, the thrust is reduced to zero, and a delay charge begins to burn. The purpose of the delay is to allow the rocket to coast up to its maximum altitude through its momentum, before the ejection is set off. When the delay is completely burned, the ejection is ignited. This generates a miniscule explosion, which discharges hot gas from the front of the engine and ejects the nosecone, along with the recovery system.

A parachute or recovery system is used to increase the surface area and air resistance or drag, therefore reducing the net force downwards during descent. This reduces the acceleration of the rocket downwards, ensuring a smooth landing.



Please see Works Cited.

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