Greetings to all, Today we are going to upload the Gravitation Class 9 Notes PDF to assist students. Class 9 Science introduces you to the most fascinating chapters and concepts you have been studying for the past few years. In Class 9 Science, you will delve a little deeper and get to know more about various natural phenomena and learn how they happen. **Class 9 Science Chapter 10** is on gravitation and the things happening around us related to it. To understand the chapter better, you can refer to the **Gravitation Class 9 notes** prepared by the highly experienced.

You will be able to understand the concepts related to gravitation, the law of **Gravitation Chapter 10** from these **revision notes** and prepare the chapter well. Every section of these notes has been compiled in such a way that students can understand the new concepts, learn the formulas, and can solve various questions easily with the help of these notes.

### Detailed Table of Chapter 10 Notes – Gravitation Class 10 Notes PDF

1. |
Board |
CBSE |

2. |
Textbook |
NCERT |

3. |
Class |
Class 9 |

4. |
Subject |
Notes |

5. |
Chapter |
Chapter 10 |

6. |
Chapter Name |
Gravitation |

7. |
Category |
CBSE Revision Notes |

## Gravitation Class 9 Notes PDF – Short Notes

**Toss a stone from a great height. What are your observations? **

- The stone, which was at first at rest, begins to move towards the ground and reaches its maximum speed right before it meets it.
- The stone is not traveling at a constant rate. Its speed fluctuates at all times, indicating that the stone is accelerating.
- A force is necessary to cause an acceleration in a body, according to Newton’s second law of motion.
- The stone was not pushed or pulled in any way. What was the source of the force?
- Sir Isaac Newton came up with the solution to this dilemma after seeing an apple fall from a tree.
- The apple, on the other hand, is unable to draw the Earth since the force it exerts on it is insignificant.

**The Universal Law of Gravitation or Newton’s Law of Gravitation:**

- The universal law of gravitation is a mathematical relationship that Sir Isaac Newton proposed to measure the gravitational force.
- According to this law “Every particle in the universe attracts every other particle with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them, the direction of the force being along the line joining the masses”.
- Consider two mass

m1m1

and

m2m2

objects separated by a distance

dd

. The gravitational force

FF

is proportional to the product of the masses, according to Newton’s law.

F ∝ m1m2 …… (1)F ∝ m1m2 …… (1)

and inversely proportional to the square of the distance between the masses

F ∝ 1d2 …… (2)F ∝ 1d2 …… (2)

Two Objects of Masses

m1m1

and

m2m2

separated by a distance

dd

Inversely proportional is always represented as directly proportional to the reciprocal of that quantity.

Combining equation

(1)(1)

and equation

(2)(2) we get

F ∝ m1m2d2F ∝ m1m2d2

F ∝ Gm1m2d2 ……. (3)F ∝ Gm1m2d2 ……. (3)

Where GG is a proportionality constant known as the universal gravitational constant.

GG is known as the universal constant because its value remains constant throughout the cosmos and is unaffected by object masses.

**Universal Gravitational Constant:**

- The mathematical form of Newton’s Law of Gravitation is

F = Gm1m2d2F = Gm1m2d2

If m1 = m2=1m1 = m2=1 and d = 1d = 1 then

F = G × 1 × 112F = G × 1 × 112

F = GF = G

- As a result, the universal gravitational constant can be defined as the gravitational force that exists between two unit masses separated by a unit distance.
- SISI

**Separated by a Distance **

dd

** **When the masses of both bodies are doubled, the force of attraction is given as;

F3 = G2m2md2F3 = G2m2md2

F3 = 4Gm2d2F3 = 4Gm2d2

F3 = 4F1F3 = 4F1

That is whenever the mass increases the force of attraction also increases.

**Dependence of Gravitational Force on Distance:**

The force of attraction between two bodies is inversely proportional to the square of their distance, according to the universal law of gravitation.

** Force of Attraction Between Two Bodies of Mass **

mm

**Separated by a Distance **

dd

** **F1 = Gm1m2d2F1 = Gm1m2d2

= Gm2d2 = Gm2d2

Here, two bodies of mass

mm

are separated by a distance

dd

and hence,

F1 = Gm2d2F1 = Gm2d2

**you can Download the Gravitation Class 9 Notes PDF by clicking on the link given below**