This post shall discuss 'Momentum and collision' as a topic for preparation of JEE Advanced and JEE Mains. The sort of questions that are asked shall also be discussed.
So there is no observable trend, you can get upto 3 questions and you may not even get 1 question. This makes it all the more risky for those who aim to score above 200. More over this chapter is the essential ground on which Rotational Mechanics is built. If we lack understanding for this chapter it is difficult to excel in it.
As far as preparation for JEE goes, in the ‘Momentum and Collision’ chapter, no single avenue is as important as a strong grip on the general principle of conservation of momentum. All the solutions of any collision problem need application of this principle. Problems may be of the ball to ball collision type, or the bullet block type, with or without friction between the block and the surface.
Next comes the vector approach to the conservation of momentum. Whenever, collision problems or any problem for that matter, occurs in a 2D or 3D paradigm, having velocities along X and Y axis, a vector approach is used in the form of i and j vectors.
Another important topic, especially for JEE Mains is Centre of mass of compound bodies. Questions related to the position of Centre of Gravity of a complex body have frequently been asked in JEE Mains (earlier AIEEE).