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# NCERT Solutions Class 11 Physics Chapter 7 Gravitation - PDF Download

Class 11

Gravitation is a very popular subject for Class 11 among students, as most of the topics you study in the future are based on this phenomenon. We should also know the difference between gravitation and gravity in order to understand more complex subjects. This chapter's gravitation consists of questions belonging to many important concepts, such as how can a body or object be shielded from gravitational influences of any nearby matter whose gravitational force is greater on earth, the sun or the moon.

We will find various complex but easy to understand topics in this chapter, such as acceleration due to gravity and finding potential energy differences between two points which are at a certain distance from the earth’s center. We will also learn that the acceleration due to gravity increases/decreases when the depth increases or altitude decreases. We will be finding questions on many topics like interplanetary motion, such as a planet revolving around the sun with a speed double that of the earth; this question will show you the use of Kepler’s laws of motion.After that we will see questions on Jupiter’s satellite radius of revolutions.

This chapter discusses the distance and speed of light among stars which are far away in a different galaxy and the time taken for the stars to complete one revolution. Here, you will also see questions related to a space shuttle’s escape velocity and its dependency on factors like an object’s mass, location, the direction of projection and the gravitational influences on it. We will be finding the kinetic energy,angular speed, total energy, potential energy, linear speed and angular momentum of an asteroid revolving around a star.

We will learn the mass of the sun in one of the questions asked below. Do you know the distance between Uranus and earth and the time taken to reach there? They will get to know it by studying this solution.

You will see here the maximum height attained by a missile when the missile is fired vertically upwards before falling down on the earth’s surface. After that, we will see the international space station’s motion around the earth and the influence of the earth’s gravitational field upon it. Do you know what will happen when two planets collide with each other, what will be their speed? We will learn it in this chapter. How a star turns into a black hole and the energy required to launch a space station on Mars are the type of questions they will find below.

In order to help you to cover this topic in a detailed and comprehensive way by solving problems, we have provided Physics Chapter 7 NCERT Solutions for Class 11 in PDF format.

## Important Concepts of NCERT Solutions for Class 11 Physics Chapter 7

Chapter 7 provides students with all the required knowledge about Gravitation and related important concepts. NCERT Solutions provides a clear understanding of the fundamental concepts of this chapter. Some of the important concepts discussed in Chapter 7 are

7.1 Introduction
7.2 Kepler’s laws
7.3 Universal law of gravitation
7.4 The gravitational constant
7.5 Acceleration due to the gravity of the earth
7.6 Acceleration due to gravity below and above the surface of the earth
7.7 Gravitational potential energy
7.7 Escape speed
7.9 Earth satellites
7.10 Energy of an orbiting satellite
7.11 Geostationary and polar satellites
7.12 Weightlessness

## Introduction

A seemingly unrelated phenomenon, observation of stars, planets and their motion has been the subject of attention in many countries since the earliest of times which has been discussed in this chapter. Observations since early times recognised stars which appeared in the sky with positions unchanged for so many years. The more interesting objects are the planets which seem to have regular motions against the background of stars.

### Kepler’s Laws

The three laws of Kepler stated as follows:

1. Law of orbits : All planets revolve in elliptical orbits with the Sun situated at one of the foci. An ellipse traced out by a planet around the sun. The closest point to the sun is P and the farthest point is A, P is called the perihelion and A the aphelion.

2. Law of areas : The line that connects any planet to the sun sweeps equal areas in equal intervals of time. This law comes from the observations that planets appear to move slower when they are far from the sun than when they come nearer.

3. Law of periods : The square of the time period of revolution of a planet is directly proportional to the cube of the semi-major axis of the ellipse traced out by the planet

### Universal Law Of Gravitation

Newton's Law of Universal Gravitation says that every particle attracts every other particle in the universe with force directly proportional to the product of the masses and inversely proportional to the square of the distance between them.

### Acceleration Due To The Gravity of The Earth

Like for earth on or near its surface, the average value of acceleration ‘a’ due to gravity is 9.8 m/s2.

## Benefits of NCERT Solutions for Class for Class 11 Physics Chapter 7

Students have not only found Class 11 Physics Ch 7 Gravitation NCERT Solutions to be extremely beneficial for class 11 exams but also for entrance exams like JEE and NEET.

Here are Some of the Benefits of Gravitation Class 11 Solutions:

• Step-by-Step Solutions: NCERT solutions for Class 11 Physics chapter 7 gravitation provide comprehensive step-by-step solutions for all the critical problems so that it becomes easy for you to comprehend every complicated concept.

• Covers All the Important Subtopics: The Gravitation ch 7 NCERT solutions class 11 covers all the major subtopics like the universal law of gravitation, Kepler’s law, escape speed, weightlessness and more.

• Important Questions: The Gravitation Class 11 questions PDF have important previous year problems which are important for your upcoming exams.

• Follow CBSE Guidelines: All the NCERT Solutions for Class for Class 11 Physics Chapter 7 are prepared by a team of highly qualified  expert subject teachers who have many years of experience in teaching. They strictly adhere to exam guide instructions while preparing every answer.

• Reduces Revision Time: The structure of Class 11th Physics Chapter 7 NCERT solutions is such that it significantly cuts down your revision time during exam. Detailed and point-wise solutions make it effortless to go through each topic and boost your study-retention capacity.

• Valid Even After CBSE Exams: NCERT physics Class 11 Chapter 7 solutions come in handy even after your CBSE exams, especially for competitive exams like JEE.

Question 1 : What are the topics in chapter 7 class 11th?

Answer : Following are the topics in chapter 7

7.1 Introduction
7.2 Kepler’s laws
7.3 Universal law of gravitation
7.4 The gravitational constant
7.5 Acceleration due to the gravity of the earth
7.6 Acceleration due to gravity below and above the surface of the earth
7.7 Gravitational potential energy
7.7 Escape speed
7.9 Earth satellites
7.10 Energy of an orbiting satellite
7.11 Geostationary and polar satellites
7.12 Weightlessness