Gravitation Class 9th Notes - Free NCERT Class 9 Science Chapter 10 Notes - Download PDF

# Gravitation Class 9th Notes - Free NCERT Class 9 Science Chapter 10 Notes - Download PDF

Edited By Vishal kumar | Updated on Mar 19, 2024 09:43 AM IST

In Chapter 10 of Class 9 Science, we look into the interesting world of gravity. Gravitation, one of nature's fundamental forces, governs the attraction between masses. Gravity shapes our universe and daily experiences in a variety of ways, from the motion of celestial bodies to the simple act of dropping a pen.

We have provided comprehensive Gravitation class 9 notes to help you understand this important chapter. These class 9 physics chapter 10 notes are a concise yet thorough resource that covers the essential concepts and key points outlined in the NCERT Textbook. Whether you're studying for an exam or just need a quick review, these Gravitation notes class 9 will help you understand the fundamentals of gravity.

These CBSE class 9 physics ch 10 notes aim to simplify complicated concepts by using clear explanations, diagrams, and examples to make them accessible and understandable to Class 9 students. This chapter will teach you about the principles of gravitational attraction, its effects on planetary motion, and its applications in a variety of real-world scenarios.

Download the PDF ch 10 physics class 9 notes to improve your understanding and grasp of this fascinating subject. With these notes, you'll be well-prepared to answer questions, solve problems, and expand your understanding of Gravitation. Discover the wonders of gravity and solve its mysteries with our comprehensive Class 9 Science notes on Gravitation.

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## NCERT Class 9 Physics Chapter 10 Notes

What is the Centripetal Force?

• We know that an object in circular motion keeps on changing its direction.

• The velocity of an object also changes.

• A force named Centripetal Force acts upon an object which keeps it moving in a circular path.

• The centripetal force is exerted from the centre of the circular path followed.

Example: Rotation of the Moon around Earth is possible because of the centripetal force exerted by Earth.

Newton's Observations

• Apple falls on the ground because the earth attracts it towards itself.

• Can Apple also attract the earth? - Yes. apple also attracts the earth as per Newton's third law. But the mass of the earth is extremely larger than Apple's mass hence, the force applied by Apple is negligible and Earth never moves towards it.

• Newton then suggested that every object in this universe attracts another object. This force of attraction is called Gravitational Force.

## Universal Law of Gravitation by Newton

• The Universal Law of Gravitation states that every object attracts another object with a specific force.

• This force is directly proportional to the product of the masses of both the objects

( F∝m1m2)

• Also, this force is inversely proportional to the square of the distances between the two objects.

F∝1/r2

• Observe the given figure below. The force of attraction between two objects is shown. The masses of the two objects are m1 and m2 respectively. These two objects are ‘d’ distance apart.

F∝m1

F∝m2

F∝1/r2

From the previous equations, we can write :

F∝m1m2/r2

Remove the proportionality we get proportionality constant G as follows:

F=Gm1m2/r2

This is the mathematical representation of Newton’s Universal Law of gravitation

SI Unit of G: Nm2 kg-2

G = 6.673 × 10-11 Nm2 kg-2

• The proportionality constant G = Universal Gravitational Constant.

Important phenomena of the universe –

• Earth’s gravitational force

• The circular trajectory of the moon around the sun

• Planets revolve around the sun

• Tides due to the moon

• Acceleration due to gravity

When an object falls towards the Earth there is an acceleration related to the movement of the object. This acceleration is the acceleration due to gravity.

• Symbole: g

• SI Unit of g: m s-2

• F=mg

• g=GM/r2

• The value of ‘g' varies in different parts of the earth.

• The value of ‘g' depends upon the distance of the object from the earth's centre.

• The value of ‘g' is greater at the poles and lesser at the equator. But we take the same value of g all over.

## What is Free Fall?

When an object falls towards the earth because of the earth’s gravity and there is no other force acting upon it, the object is in a free-fall state. Air resistance is negligible.

The value of ‘g' is the same on the earth, thus the equations of motion for an object with uniform motion are valid.

v=u+gt

s=ut+gt2/2

2gs=v2-u2

## Mass v/s Weight

 Mass Weight Mass is the quantity of matter in an object. The weight of an object is the force because of which the gravitational pull of the earth attracts the object. Mass is a scalar physical quantity Weight is a vector physical quantity The mass of an object is always constant. The weight of an object can vary at different locations on earth. Mass is never zero Weight can be zero at places where there is no gravitational force, i.e. space Symbol: m Symbol: W g = acceleration due to gravity W = mg SI Unit: kg SI unit: N

Significance of NCERT class 9 physics chapter 10 notes

Comprehensive Revision: The NCERT Gravitation class 9 notes provide a comprehensive overview of the chapter, allowing students to thoroughly review all key concepts.

Detailed Understanding: These class 9 physics chapter 10 notes provide detailed explanations of the chapter's main concepts, ensuring that students understand the principles of gravitation.

Simplicity: The Gravitation notes class 9 are intended to be straightforward and easy to understand, making complex concepts more accessible to students.

Step-by-Step Approach: Each concept is explained step by step, allowing students to follow along and grasp the material more effectively.

CBSE Syllabus Coverage: Because Gravitation is part of the CBSE Science syllabus for class 9, these notes are perfectly aligned with the curriculum, ensuring that students cover all of the required topics.

Offline Preparation: CBSE class 9 physics ch 10 notes are available in PDF format, allowing students to download and access them offline, allowing for convenient preparation at any time and from any location.

## NCERT Class 9 Exemplar Solutions for Other Subjects:

### Class 10 Chapter Wise Notes

 NCERT Class 9th Science Chapter 1 Notes NCERT Class 9th Science Chapter 2 Notes NCERT Class 9th Science Chapter 3 Notes NCERT Class 9th Science Chapter 4 Notes NCERT Class 9th Science Chapter 5 Notes NCERT Class 9th Science Chapter 6 Notes NCERT Class 9th Science Chapter 7 Notes NCERT Class 9th Science Chapter 8 Notes NCERT Class 9th Science Chapter 9 Notes NCERT Class 9th Science Chapter 10 Notes NCERT Class 9th Science Chapter 11 Notes NCERT Class 9th Science Chapter 12 Notes NCERT Class 9th Science Chapter 13 Notes NCERT Class 9th Science Chapter 14 Notes NCERT Class 9th Science Chapter 15 Notes

1. What are the main points discussed in NCERT notes for class 9 Science chapter 10?

NCERT Class 9 Science chapter 10 notes covers and discusses the following topics in-depth:

Universal Gravitational Law

Acceleration due to gravity

Difference between Mass and Weight

2. How will CBSE class 9 Science chapter 10 notes benefit students?

Subject experts have created Class 9th Science chapter 10 notes that will give you further information on the topics. You can reinforce your foundation with these class 9 science chapter 10 notes. Important concepts are well-explained here. Every aspect of gravitation discussed in the CBSE syllabus is covered in these notes.

3. What is free fall?

When an object falls towards the earth because of the earth’s gravity and there is no other force acting upon it, the object is in a free fall state. Air resistance is negligible.

4. Is Gravitation class 9 notes important for JEE Main?

Yes, understanding the basic principles of gravitation from Class 9 notes can contribute to a stronger foundation in physics, which may indirectly benefit JEE Main preparation by enhancing conceptual understanding and problem-solving skills.

5. Why do objects fall towards the Earth?

Objects fall towards the Earth due to gravity, which is the attraction between the object's mass and the mass of the Earth. Gravity accelerates objects towards the Earth's centre at a rate of 9.8 m/s².

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 Option 1) 0.02 Option 2) 3.125 × 10-2 Option 3) 1.25 × 10-2 Option 4) 2.5 × 10-2

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