Rotational Motion made easy for JEE

3 min readDec 16, 2022


Rotation, or spin, is the circular movement of an object around a central axis. A two-dimensional rotating object has only one possible central axis and can rotate in either a clockwise or counterclockwise direction. A three-dimensional object has an infinite number of possible central axes and rotational directions.

Why it is one of the toughest!

The reason why rotational mechanics is a challenging subject is significant. The combination of all the mechanics is the cause.

You see, there isn’t much of a connection between the chapters in electrodynamics. However, you should be knowledgeable about kinematics, laws of motion, friction, centre of mass, momentum, etc. when it comes to RM.

As a result, each time you answer a question from rotational mechanics, you are actually answering a question from each chapter of complete mechanics.

And by the time one begins with RM, the majority of people have forgotten most of the earlier topics, making RM seem like a difficult subject.

What should be done before Rotational Motion?

All the mechanics ideas and fundamental physics math concepts are covered in the chapter on rotational motion: You will research the following subjects:

Moment of inertia: A thorough understanding of integral calculus is necessary for this.

Torque: For which understanding of all types of forces and vectors is necessary.

Work-energy theorem and energy balance concepts are all included in the Kinetic Energy of Rotation.

You must have a thorough understanding of linear momentum in order to comprehend angular momentum.

When rolling, you must have a solid understanding of friction and circular motion.

Combined Translational and rotational motion: A thorough understanding of all mechanics concepts, including rotational dynamics, is necessary for this topic.

Tips & Tricks

Don’t Mess up

Devote at least 1–2 hours per day to reading theory and formulas, reading theory on some days. Then begin by using notes, move on to HC Verma, and then revise some of DC Pandey’s formulas.

Cover the basics

Yes, Cover the basics, as there can be n number of questions from this chapter and all require a good concept. And even if something irrelevant occurs that you have never come across, you’ll be able to solve that by hook or crook.

● If the above point is fulfilled you can always took up the chapter in full swing starting with the very basics of Moment of Inertia. Grasp the basics of deriving the MOI of all bodies by integration techniques. It helps a lot for JEE. Don’t just remember the result. Learn how to derive.

● Then comes the basics of Torque.

For this first thing to know is to find the direction of torque by the Right Hand Thumb Rule. Calculation of Torque is easy while finding it’s direction is tough.

● Once you get hold to above concepts, Angular Momentum hold the key now. Grasp this concept as it is one of the most important one for JEE. Numerous questions have been asked and at least one question from here every year is a surety.

● Now that the base for the chapter is made, Combined Transactional and Rotational Motion will take your troll. Pure Rolling forms the most important part in this. One question from this part is again 99% sure.

Notes Sample :

These notes are provided by Ashta Prasad on Quora, Click on this link to find all the notes.

Always remember: -

“If You Can Dream It, You Can Achieve It”

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Now that you’re here, we’re sure that you’re going to pull up your socks and be ready for a crazy ride of Rotational Motion. We’re pretty confident that you’ll do well, but if you get stuck anywhere or find any doubt regarding anything, don’t forget we’re here at DoubtConnect. DoubtConnect is an instant doubt solving app, which provides you with master faculties who have a grip on their subject.

Doubt connect caters subject like Physics, Chemistry and Math, you can even find more blogs on Chapters made easy series by clicking here, So get back to your study and let Doubt connect be your ultimate maths doubt solver.

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