Geostationary and Polar Satellites

The lowest altitude by an Earth observation satellite in orbit is _____. 

What are low height satellites?

Why are polar satellites not used for radio and television broadcast?

How does a polar satellite revolve around the earth?

It is possible to put an artificial satellite in orbit in such a way that it always remains directly over New Delhi.

The _____satellite constellation also uses a polar orbit to provide telecommunications services.

Polar satellites:

As you have learnt in the text, a geostationary satellite orbits the earth at a height of nearly $36,000 \mathrm{km}$ from the surface of the earth. Potential due to earth’s gravity at the site of this satellite is $-9.4\times {10}^n {\mathrm{Jkg}}^{-1}$. Find $n$ (Take the potential energy at infinity to be zero). Mass of the earth$=6.0\times {10}^{24} \mathrm{kg},$ radius$=6400 \mathrm{km}$. 

If a satellite has to orbit the earth in a circular path every $6 \mathrm{h}$, at what distance from the surface of the earth should be satellite placed (radius of earth, $R_{\mathrm{e}}=6400 \mathrm{km}$) (assume, $\frac{GM}{4{\pi }^2}=8.0\times {10}^{12} \mathrm{N} {\mathrm{m}}^{-2} {\mathrm{kg}}^{-1}$, where $G$ and $M$ are gravitational constant and mass of earth and ${10}^{1/3}=2.1$),

Calculate the height of the communication satellite. $(\mathrm{Given}: G = 6.67\times {10}^{-11} {\mathrm{Nm}}^2/{\mathrm{Kg}}^2 , M = 6\times {10}^{24} \mathrm{kg}, R = 6400 \mathrm{km})$

What is geo-stationary satellite? State uses of satellites.

A synchronous satellite goes around the earth once in every $24\mathrm{ }\mathrm{h}.$ What is the radius of orbit of the synchronous satellite in terms of the earth's radius?
(Given: mass of the earth, ${\mathrm{M}}_{\mathrm{E}}=5.98\times {10}^{24}\mathrm{ }\mathrm{k}\mathrm{g}$ , radius of the earth, ${\mathrm{R}}_{\mathrm{E}}=6.37\times {10}^6\mathrm{ }\mathrm{m}$ and universal gravitational constant, $\mathrm{G}=6.67\times {10}^{-11}\mathrm{N}\mathrm{ }{\mathrm{m}}^2\mathrm{ }\mathrm{k}{\mathrm{g}}^{-2}$)

Polar satellites

A period of geostationary satellite is

LANDSAT series of satellites move in near polar orbits at an altitude of