NCERT Solutions for Class 9 Science Chapter 10 Gravitation: When we shake a tree leaf falls down because of gravitational force due to earth. When we drop a pen it falls gown due to gravitation. In NCERT Solutions for Class 9 Science Chapter 10, we study the gravitational force between two bodies, acceleration due to gravity, free fall, buoyancy force, and relative density. Throughout NCERT Solutions for Class 9 Science we will take the acceleration due to the gravity of earth as 9.8ms^{2}.
NCERT Solutions for Class 9: Universal law of gravitation
The gravitational force of attraction between two bodies is directly proportional to the product of their masses and inversely proportional to the square of the distance between the object. That is if two masses M and m are separated by a distance d apart then the gravitational force
Where G is called universal gravitational constant whose value is
NCERT Solutions: Acceleration due to gravity
The value of acceleration due to the gravity of earth (g) on an object is given by the equation
Where M is the mass of the earth and d is the distance between the object and the earth. If the object is on the surface of earth or near to earth then the radius of the earth is approximately = distance between the object and the earth. Therefor
Where R is the radius of the earth.
An important topic of NCERT Solutions for Class 9 Science Chapter 10 is BUOYANCY
We have experienced that it is easy to lift a bucket of water from a well till the surface of the water and above the water weight increase. The less weight inside the water is due to a force exerted by water against the weight of a bucket of water. This force exerted by the liquid is known as upthrust or buoyant force. All the objects experience a force of buoyancy when they are immersed in a fluid. The magnitude of the upthrust (buoyant force) depends on the density of water. Objects of density less than that of a liquid float on the liquid and the objects of density greater than that of a liquid sink in the liquid.
The main topics of NCERT Solutions for Class 9 Science Chapter 10 Gravitation are given here:
10.1 Gravitation
10.1.1 Universal Law of Gravitation
10.1.2 Importance of The Universal Law of Gravitation
10.2 Free Fall
10.2.1 To Calculate The Value Of g
10.2.2 Motion of Objects Under the Influence of Gravitational Force of the Earth
10.3 Mass
10.4 Weight
10.4.1 Weight of an Object on the Moon
10.5 Thrust and Pressure
10.5.1 Pressure in Fluids
10.5.2 BUOYANCY
10.5.3 Why Objects Float Or Sink When Placed on The Surface of Water?
10.6 Archimedes’ Principle
10.7 Relative Density
The difference between mass and weight is also mentioned in NCERT Solutions
What is the difference between weight and mass?
Mass of an object is a measure of inertia. It is the measure of the amount of matter in a body and is constant everywhere. But weight is the force due to gravity. If m is the mass of the object and g is the acceleration due to gravity then weight w=mg. Weight varies according to the distance since g is dependent on distance. The weight of an object in the earth is different from the weight of the same object in the moon since the value of g is different in the moon and Earth. But the mass of the object will be the same in the moon and earth.
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Chapter 2 

Chapter 3 

Chapter 4 

Chapter 5 

Chapter 6 

Chapter 7 

Chapter 8 

Chapter 9 

Chapter 11 

Chapter 12 

Chapter 13 

Chapter 14 

Chapter 15 
NCERT Solutions for Class 9 Maths 
NCERT Solutions for Class 9 Science 
Q. 3. What is the magnitude of the gravitational force between the earth and a object on its surface? (Mass of the earth is and radius of the . earth is)
Write the formula to find the magnitude of the gravitational force between the earth and an object on the surface of the earth.
Q. 8. What is the acceleration of free fall?