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A rocket is a missile, spacecraft, aircraft orother vehicle which obtain thrust from a rocketengine.
The exhaust is formed from propellants carriedwithin the rocket before use in all rockets.
Rocket engines push rockets forwards bythrowing their exhaust backwards extremelyfast.
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Principle of Newton's third law
The expansion of nozzles on a high pressure fluid and the rocketengines combustion accelerate the fluid to high speed andexerts a large reactive thrust on the rocket which propels therocket forwards.
The pressures acting on the combustion chamber and nozzlecause reactive thrust.
In a closed chamber, the pressures are equal in each directionand no acceleration occurs.
The remaining pressures give a resultant thrust on the sideopposite the opening, and these pressures are what push therocket along. Using a nozzle gives more force also since theexhaust also presses on it as it expands outwards doubling thetotal force.
Theory
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Conservation of momentum
Since a rocket, propellant and exhaust in flight, without anyexternal, may be considered as a closed system, the totalmomentum is always constant. .
As the remaining propellant decreases, rocket vehicles become
lighter and their acceleration tends to increase until thepropellant is exhausted. This means that much of the speedchange occurs towards the end of the burn when the vehicle ismuch lighter.
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Flying rockets are primarily
affected by the following:
Thrust from the engine(s) Gravity from celestial
bodies
Drag if moving inatmosphere
Lift; usually relatively
small effect except
for rocket-poweredaircraft
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The first use of true rocketsDate : 1232
Who : Chinese and the Mongols
Event : War between Chinese and the Mongols the Chinese created "arrows of flying fire."
a simple form of a solid-propellant rocket.
A tube, capped at one end, contained gunpowder. The otherend was left open and the tube was attached to a long stick.
The stick acted as a simple guidance system that kept the
rocket headed in one general direction as it flew through the
air.
History
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Until..
In 1898,
Konstantin Tsiolkovsky, a Russian schoolteacher
proposed the idea of space exploration by rocket.
suggested the use of liquid propellants for rockets inorder to achieve greater range
Tsiolkovsky has been called the father of modern astronautics.
When?
Who?
What?
How?
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Structure Usually plastic,reduces drag
Usually aparachute orstreamer, slowsrocket downduring descent
Flameproof, tissue-likesubstance that preventsrecovery device frombeing scorched byejection charge
Prevents motor frombeing forced intorocket
Stabilizes rocket during flight
Primary function is topropel the rocket
Attaches nose cone to bodytube, takes the shock ofrecovery device ejection
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MilitaryScience and research
Rescue
Space flight
Entertainment
Uses of rocket
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A rocket and its payloadtogether are generallyreferred to as a missile
when the weapon has aguidance system or as arocket if it is unguided.
Examples : Anti-tank and anti-aircraft
missiles use rocket engines toengage targets at high speed at arange of several miles
Intercontinental ballisticmissiles can be used to delivermultiple nuclear warheadsthousands of miles
Anti-ballistic missiles try to stopthem.
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Sounding rockets are
commonly used to carryinstruments that take
readings from 50
kilometres (31 mi) to 1,500
kilometres (930 mi) above
the surface of the Earth,
the altitudes between
those reachable by
weather balloons and
satellites.
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Multi stage rocket Solid rocket
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Unload the unnecessary parts during flight
Different motor for different situation
Advantages of Multi stage rocket
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Lower specific impulsion
Shut down of rocket
More complex and harder to build
Disadvantages of Solid rocket
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Impacts to Environment & Society
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Affect the depletion of stratospheric ozone
Impact 1
Emit reactivegases that causeozone moleculesto break apart
Dischargemicroscopic particlesof soot andaluminium oxide,
which may increasethe rate at whichthose gases wreak
havoc
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Global climate change
Impact 2
The exhaust from space-ship engines does addseveral kilotons of carbon
dioxide to the atmosphereevery year.
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Change the radiation balance in the atmosphere
Impact 3
aluminium oxide, for example, reflect the visiblelight from the sun back into space, which cools theEarth.
those particles can also absorb infrared radiationemanating from the planet's surface, essentiallytrapping heat the way a greenhouse gas does.
These may also increase rates of skin cancer andcataracts.
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Perchlorate impairs the proper functioning of thyroidgland
Improper regulation of thyroid function is the leadingknown cause of neurological impairment world wide.
At higher level of exposure, perchlorate causes thyroidcancer and harm the immune system.
Impact 4
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