# NCERT Solutions for Class 9 Science Chapter 10 – Gravitation

NCERT Solutions for Class 9 Chapter 10 Gravitation include topics like the laws of gravitation, gravitational force, the magnitude of gravitational force and gravitation constant. The chapter of NCERT Solutions for Class 9 Science focuses on the basic and fundamental understanding of gravitation and the various terms and applications related to it. It has a total of 6 exercises and 33 questions. It also discusses the relation between mass and force, velocity in a vertically upward direction, density, relation between gravitation and distance etc.

Preparing NCERT Solutions for Class 9 Science Chapter 10 will test your knowledge and application skills of all the topics of the chapter. If you get stuck at any point, our NCERT solutions will help you out. Whether it be long answers, numerical or short answer questions, we have provided stepwise solutions for all kinds of NCERT exercises of the chapter.

## Important Topics of NCERT Class 9 Science Solutions Chapter 10 – Gravitation

**Universal Law of Gravitation **

CBSE Class 9 Science NCERT Solutions Class 9 Science chapter 10 introduces the universal law for gravitation which states that every object that is present in this universe attracts every other object that exists. The attraction forces between all these objects are known as the gravitational force. The force that acts between two bodies is directly proportional to the product of their masses and this force is inversely proportional to the square of the distance that exists between their centres.

In the case of two objects which have their masses as m1 and m2, the distance between them is r and the force is F, then the force of attraction between them is given as –

**F = (Gm1m2)/r*r**

Here G is referred to as the universal gravitation constant.

**Free Fall **

The concept of free fall has also been discussed in the chapter. The earth has gravity which attracts every object towards its centre. Whenever an object is taken to a particular height and is released from there, it falls towards the surface of the earth due to the influence of the gravitational force that the earth applies to it. Such a motion of an object towards the earth, under the earth’s gravitational force, is known as Freefall.

**Mass and Weight **

These terms might have seemed to be similar to you, but this chapter will explain the difference between these. Mass is the quantity of matter that is contained in a body and therefore it is the measure of inertia of a body. It is a constant quantity and it only has a magnitude. Its SI Unit is the kilogram.

Weight, on the other hand, is the force of gravity that acts of a body and therefore it is the measurement of gravity on a body. Unlike mass, it is a variable quantity. It is not constant and keeps changing according to the places. It has a direction along with a magnitude and its SI Unit is Newton which is also the SI Unit of force.

**Buoyancy **

The force that is exerted in an upward direction, by the liquid on an object that is immersed in it, is known as buoyancy. When we push the object deeper in water, the force seems to get stronger in its strength while applying a resistance or an opposite force in the upward direction.

**Numerical problems **

The chapter has a fair share of numerical problems which again deal with the concepts and formulas that you will learn in the chapter.

Example –

The gravitational force on the surface of the moon is only 1/6 as strong as the gravitational force of the earth. What will be the weight in Newtons, of a 10 kg object on the moon and on earth?

Solution –

Weight of the object on moon = 1/6 x weight of the object on earth

Also,

Weight = Mass x Acceleration

Acceleration due to gravity, g = 9.8 m/s*s

Therefore, weight of the 10 kg object on Earth = 10 x 9.8 = 98 N

And, the weight of the same object on the moon = 1/6 x 98 = 16.3 N

Answer –

Weight of the 10 kg object is 98 N when on earth and it is 16.3 N when on the moon.

### Exercise-wise discussion of NCERT Class 9 Solutions Chapter 10 Gravitation

- Science NCERT Solutions for Class 9 Chapter 10 Gravitation consists of a diverse set of questions. There are questions which ask you to define the Universal law of gravitation, its formula, free fall etc.
- There are also questions which ask you to present a comparative analysis amongst physical quantities like mass and weight.
- Further, there are reasoning questions which require you to apply the logic learned from the chapter on daily life instances.
- There are numerical questions where you will have to apply the formulas that have been discussed in the chapter. These numerical problems will ask you to find quantities such as the force, the height, or the gravitation quotient from the given scenarios and values.

### About NCERT Solutions for Class 9 Chapter 10 Gravitation by Instasolv

You can refer to our NCERT Solutions for Class 9 Chapter 10 any time and find quick solutions to all your queries. Our best science subject matter experts have created these solutions as per the latest CBSE syllabus for class 9 so they will surely help you in exam preparation. Our NCERT solutions do not include any complex topics or vocabulary keeping in mind the competency level of Class 9 students.