Satellites - Important points to be noted

1.  Orbital velocity of satellite is independent of mass of the satellite but depends on mass of planet and radius of orbit.

2. A satellite orbiting around a planet will have both Potential energy and Kinetic energy. Here Potential energy is negative and Kinetic energy is positive.

3. Total energy of satellite is negative.

4. With the increase of height of orbit from surface of planet, for a satellite

              a) Potential energy increases (from more negative to less negative)
              b) Kinetic energy decreases
              c) Orbital velocity decreases
              d) Total energy increases
              e) Period of revolution increases

5. A satellite orbiting very close to surface of Earth is known as its surface satellite. Orbital velocity for such a satellite is V = √gR = 8 Km.S⁻¹.

6. Relative velocity of parking satellite with respective to Earth is zero.

7. Orbital linear velocity is about 3 Km.Sec⁻¹.

8. A satellite cannot be coast in a stable orbit in a plane not passing through the Earth's center.

9. If two satellite move around the Earth in its equitorial plane such that one moves from West to East and other from East to West and other from East to West, the time period of revolution of first satellite will be more compared to other.

10. If a rocket launched in equitorial plane from West to East, advantage is up to 0.47 Km.Sec⁻¹  in the launching speed.  

11. If the Kinetic energy of an orbiting satellite is E, its Potential Energy will be -2E and total energy will be -E.

12. If a body is in a satellite which does not produce its own gravity, its true weight in that satellite W' is given by

W'/W =mg'/mg  ; W' = W/(1+[h/R])²

W - Weight of body on Earth
 h  - Height of orbit of satellite
 R - Radius of Earth

so true weight is lesser than its weight on Earth.  

13.  Apparent weight of a body in a satellite is zero and is independent of radius of orbit .


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