Motion of Satellites and Planets


Motion of Satellites and Planets

Gravitation is a chapter which isn't that important from the point of view of JEE advanced, but is important from the point of view of JEE Main and Indian National Physics Olympiad (INPhO). Those aiming to perform well in olympiads can absolutely not afford to ignore this chapter. Brilliant questions are asked from motion of satellites and planets in Indian National Physics Olympiad.



For mastering this chapter, students should have a fundamental understanding of the following topics:

  1. Law of Gravitation – understanding the Universal Law of Gravitation is absolutely important. Students should be familiar with the statement of the law of Gravitation. They should also know the conditions under which the law is valid and the condition under which it isnt applicable.
  2. Gravitational Field and Potential - Students should properly understand the concept of Gravitational field. There are a large number of formulae of Gravitational field by various objects. Examination paper setters expect the students to know these formulae and apply them directly as an when needed (skipping the derivation). Also, you should well understand the definition of Gravitational potential as the work done under certain circumstances. At the same time, you should remember the various formulae involving Gravitational potential calculation by objects of different types.
  3. Acceleration due to gravity – Since most students are already familiar with acceleration due to gravity, this topic is quite straight forward.
  4. Kepler's law – these are the most important laws and are central to the understanding of the motion of satellites and planets. You just cannot skip them at any cost! These laws are the most important set of rules and you will need them to actually solve the various problems involving the motion of satellites and planets.
  5. Escape Velocity – This is fairly a simple topic – direct application of the law of gravitation and the concept of gravitational potential.

It is important to practice a large number of problems from this chapter. This chapter isn't a huge chapter like many others, but the problems of Kepler's laws are mind bending and may sometimes need a deep knowledge of calculus (differential and integral calculus). If at any point you feel that you are unable to solve some problem, make sure you understand the associated theory properly. Read as much as you can in this chapter. Resnick Halliday and Walker by Wiley publishers is the best book to master not only the motion of satellites and planets, but also the chapter on Gravitation as a whole.


About the Author

Aman Goel IIT B2 Aman Goel is B.Tech, computer science and engineering undergraduate student at Indian Institute of Technology, Bombay. Born in a business oriented family of Kanpur he secured an All India Rank 33 in JEE advanced 2013 and also scored 323/360 in JEE main 2013. He has also cleared Indian National Physics and Chemistry Olympiads, and KVPY. In his free time, he likes to write articles related to JEE preparation. He loves speedcubing (the art of speed solving a Rubik's cube) and also loves to play computer/mobile games.


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