## Revision Notes for CBSE Class 11 Physics Chapter 6 (System of Particles and Rotational Motion) - Free PDF Download

## FAQs on Systems of Particles and Rotational Motion Class 11 Notes CBSE Physics Chapter 6 (Free PDF Download)

1. What do You Understand by Parallel and Perpendicular Axis Theorem?

**Ans:** Parallel axis theorem states that the moment of inertia of a body is the sum of moment of inertia about a parallel axis passing through the centre of mass and Ma^{2}, where M is the mass of the body and a is the perpendicular distance between the two axes.

Perpendicular axis theorem states that the moment of inertia of a body about a perpendicular axis can be calculated by the sum of the moment of inertias of the body about two axes perpendicular to each other and intersects at the point where the perpendicular axis passes.

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2. Define Angular Momentum?

**Ans:** Angular momentum is defined as rotational momentum or moment of momentum. It is the rotational equivalent of linear momentum. Conservation of angular momentum states that angular momentum is a conserved quantity, which means that the angular momentum in a closed system remains unchanged. Mathematically,

L = r̅ × p̅

It can also be defined as the product of Moment of Inertia and the angular velocity.

L = Iω

Where,

I = Moment of Inertia

ω = Angular velocity

The SI unit of angular momentum is kgm^{2}/s.

3. How can I download the PDF file of notes of Chapter 6 of Class 11 Physics?

**Ans:** The steps mentioned below will help you to download the PDF file of notes of Chapter 6 of Class 11 Physics:

Visit the page Class 11 Physics Revision Notes for Chapter 6.

This will help you to reach the page of Vedantu.

As the link will open, the website of Vedantu will appear on your device screen.

The “Download PDF” option will be available on the page.

By clicking this option you will get access to download the PDF file.

These notes are available at free of cost and can be accessed from the Vedantu app as well.

4. What are the concepts discussed in Chapter 6 of Class 11 Physics?

**Ans:** The chapter “System of Particles and Rotational Motion” is a very important and scoring chapter for a student of Class 11. This chapter is very easy to understand. The themes or points mentioned in this chapter are:

The motion of Centre of Mass

Centre of Mass of a uniform rod, rigid body and 2 particle system.

Momentum Conservation and Momentum of Force

Torque

Moment of Inertia

Laws of Preservation of Angular Momentum and Angular Momentum

Radius of Gyration

Perpendicular and Parallel Axis Theorem

5. Note down some differences between the centre of gravity and the centre of mass.

**Ans: ****Centre of Mass –** It is defined as the point where the total mass of the body is supposed to be concentrated to describe the motion of the body as a particle. This does not lie in the object's body.

**Centre of Gravity – **The point where the total weight of the body is presumed to be concentrated, which means that on this point, the resultant gravitational force on all the particles of the body acts. It is always present in the object's body.

6. Write the characteristics of the angular momentum.

**Ans:** The important features of the angular momentum are:

With respect to a point, the angular momentum provides an idea regarding the strength of its rotational tendency about that point.

The definition of angular momentum is in terms of mass, distance from the reference point and particle's velocity i.e. L = mvr.

It is important to know about the vector concept of angular momentum. With the help of the right-hand rule, the direction of angular momentum can be determined. Velocity and distance are vertical to the direction of angular momentum.

7. What is the moment of inertia of a body rotating about the axis?

**Ans:** The moment of inertia of a body rotating about the axis is defined as the sum of the product of the square of the distance from the axis and mass of each particle of the body.

This helps to know about the force that the body would take to slow down, speed up or stop.

The factors on which the moment of inertia of a body rotating about the axis depends on:

Body’s distance from the axis.

Mass distribution of the body.