Satellite Motion

Monika V SikandPh.d StudentStevens Institute of TechnologyDepartment of Physics.Light and Life Laboratory. Hoboken.

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OBJECTIVE

• Review laws of motion and gravitation

• Satellite motion• Escape velocity• Geosynchronous

orbit(Telecommunication satellites)

Newton’s laws of motion

I. Law of Inertia

II. F=ma

III. Action-ReactionQuickTime™ and a

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Isaac Newton January 4, 1643 -March31,1727

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What is Gravity?

Gravity is a pulling force

It pulls things down towards the earth

Things fall because of gravity

Things always fall down

Why do people not fall off the earth?

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Newton’s Law of Gravitation

Gravity holds everything and every one on the earth

In Space, Gravity keeps the planets moving around the sun

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Gravity on earth and moon

So how can we understand orbital motion?

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Motion of the ball on earth

Example

Earth’s curvature

Satellite

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Smaller body revolving around a larger body

Natural satellites

Moon, planets, comet

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Artificial satellites

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Weather , spy , communication

Escape velocity

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Artificial satellite in a circular orbit around earth first achieving a speed of 7900m/s.

If speed greater than 7900m/s satellite has a elliptical orbit.

If velocity greater than 11km/s then satellite leaves earth’s orbit and has a escape orbit. The escape orbit’s velocity is called escape velocity.

Figure 7-22Satellite orbits

Geostationary Earth Orbit (GEO)

Orbit is synchronous with the earths rotation.

From the ground the satellite appears fixed.

Altitude is about 22,300 miles or 36,000Km.

Coverage to 40% of planet per satellite.

Conclusion

• Newton’s law of gravitation F =Gm1m2/r2

• Satellites are revolving bodies around earth.

• Escape velocity is the maximum velocity required to escape the earth’s orbit.

• Geostationary orbits are synchronized with earth’s rotation at 36000 km of height.