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August 7, 202239 Insightful Publications

**NCERT Solutions for Class 9 Science Chapter 10:** NCERT Class 9 Science Chapter10 is all about Gravitation. Students study the universal laws governing Gravitation, go through detailed explanations, and learn various formulas. This chapter also teaches the essential concepts of velocity, acceleration, force, work, and energy. The subject matter experts at Embibe have developed the Class 9 Science Chapter 10 Solutions by keeping the CBSE guidelines and examination pattern in mind.

Embibe’s Gravitation Class 9 question and answer PDF will help students get an in-depth conceptual understanding of the Class 9 Science Chapter 10 in-text questions. They can also take the help of the solutions while doing their homework or internal assessments. Keep reading to know more about CBSE Class 9 science chapter 10 question answers.

In this chapter, students will learn about Gravitation and the Universal Law of Gravitation. In this article, along with the Gravitation force, Universal Law of Gravitation, and its importance, mathematical equations are discussed. Later, the concepts of free fall, the value of *g*, and the motion of objects under the influence of the earth’s gravitational force are discussed.

Students will also get to know the differences between mass and weight and how to calculate an object’s weight on the Moon. This chapter consists of many numerical problems that must be understood and practised diligently.

Listed below are some of the major concepts students will learn in CBSE NCERT Class 9 Science Chapter 10.

- Universal Law of Gravitation and its Importance
- Characteristics of Gravitational Forces
- Concept of Free Fall
- Difference between Gravitation Constant and Gravitational Acceleration

Before getting into the details of CBSE **NCERT solutions for Class 9 Science** Chapter 10, let us have a look at the topics included in this chapter:

Section | Topic Name | Summary |
---|---|---|

10.1 | Gravitation | Students understand gravitational force through the example of the motion of the moon around the earth. The universal law of gravitation is also an important concept in this section. |

10.2 | Free Fall | Students understand about free fall – Whenever objects fall towards the earth under this force alone, we say that the objects are in free fall. And how to calculate the value of g through solved textbook examples. |

10.3 | Mass | Students learn that the greater the mass, the greater is the inertia. It remains the same whether the object is on the earth, the moon or even in outer space. Thus, the mass of an object is constant and does not change from place to place. |

10.4 | Weight | Students learn how to calculate weight along with some important formulas associated with it. |

10.5 | Thrust and Pressure | Students learn about pressure in liquids and buoyancy. |

10.6 | Archimedes Principle | Archimedes Principle – When a body is immersed fully or partially in a fluid, it experiences an upward force that is equal to the weight of the fluid displaced by it. |

10.7 | Relative Density | Relative Density – The relative density of a substance is the ratio of its density to that of water. |

Here, students can find the solutions to in-text and exercise questions for NCERT Science Chapter 10 Class 9 questions. They can also download the answers for CBSE Class 9 Science Chapter 10 as a PDF to practice offline. The detailed solutions to NCERT Class 9 Science Questions have been provided directly after each question.

**Q.1. How does the force of gravitation between two objects change when the distance between them is reduced to half?Solution:** The law of gravitation states that the gravitational force F acting between two objects is inversely proportional to the square of the distance r between them. Hence, if the distance is reduced to half, then the gravitational force would become four times.

**Q.2. Amit buys few grams of gold at the poles as per the instruction of one of his friends. He hands over the same when he meets him at the equator. Will the friend agree with the weight of gold bought? If not, why?****Solution:** Amit’s friend will not agree with the weight of the gold bought.

Weight of a body on the earth is given by:

W=mg

where,

m = Mass of the body

g = Acceleration due to gravity

The value of g is greater at poles than at the equator. Therefore, the same mass of gold weighs lesser at the equator than at the poles.

**Download NCERT Solutions for Class 9 Science Chapter 10 PDF**

Here we have provided you with a few questions from CBSE Class 9 Science Chapter 10 that are important from the examination point of view.

**1 and 2 Mark Questions**

- What is the acceleration of free fall?
- What is the SI unit of Pressure and Relative Density?
- What is the magnitude of the gravitational force between the earth and a 1 kg object on its surface?
- Gravitational force on the surface of the moon is only 1/6th as strong as gravitational force on the earth. What is the weight in newtons of a 10 kg object on the moon and on the earth?

**3 Mark Questions**

- Write the formula to find the magnitude of the gravitational force between the earth and an object on the surface of the earth.
- What are the differences between the mass of an object and its weight?
- Why does an object float or sink when placed on the surface of water?
- What is the importance of universal law of gravitation?

**5 Mark Questions**

- A stone is allowed to fall from the top of a tower 100 m high and at the same time another stone is projected vertically upwards from the ground with a velocity of 25 m/s. Calculate when and where the two stones will meet
- The Olympic high jump record is 2.45m held by Cuba. Let acceleration due to gravity on earth be 1m/s^2 and not 10m/s^2 . Calculate the height to which the jumper would have jumped?
- State the factors on which acceleration due to gravity (g) depends.
- The radius of earth is 6370 Km and that of mars is 3400 Km. If an object weighs 200 N or earth, what will be its weight on mars. The mass of mars is 0.11 that of earth.

Apart from the fact the NCERT solutions are created according to the latest syllabus, exam pattern and marking scheme, there are other reasons why students must make it a point to refer to them. They are listed below.

- Easy to understand solutions to every question in the NCERT Class 9 Science Book.
- Students will be learning under the supervision of qualified and experienced teachers.
- All the questions provided in this article are as per the latest syllabus prescribed by CBSE Board.
- Special attention should be given to exam-oriented questions.
- Some additional learning resources are also offered, such as sample papers and previous year’s question papers.

**Ans**: The universal law of gravitation states that every object in the universe attracts every other object with a force called gravitational force. The force acting between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.

**Ans**: When an object falls freely from a certain height towards the earth’s surface, its velocity changes. This velocity change produces acceleration in the object known as acceleration due to gravity, represented by the letter *g*.

The gravity-based acceleration value is,

g=9.8ms^{-2}

** Ans**: The moon’s mass is 1/100 times and 1/4 times the earth’s radius. As a result, when compared to earth, the gravitational attraction on the moon is about one-sixth. Thus, an object’s weight on the moon is 1/6th its earth weight.

**Ans**: The upward force possessed by a liquid on an object that’s immersed in it is referred to as buoyancy.

**Ans:** The bag of cotton is heavier than the bar of iron. The cotton bag has a larger air thrust than the iron bar. The weighing machine, therefore, indicates a smaller cotton bag weight than its actual weight.