Gravitation
1. Gravitation
Gravitation is the force of attraction between any two objects having mass.
This force:
keeps planets in their orbits
causes objects to fall towards the Earth
is present between all bodies in the universe
2. Universal Law of Gravitation
Every object in the universe attracts every other object with a force that:
is directly proportional to the product of their masses
is inversely proportional to the square of the distance between their centres
Mathematical Form:
𝒎𝟏 𝒎𝟐
F= G
𝒓𝟐
Where:
F = gravitational force
G = universal gravitational constant
m₁, m₂ = masses of the two objects
r = distance between their centers
3. Importance of Gravitation
Gravitation:
binds objects to the Earth
keeps the Moon around the Earth
keeps planets around the Sun
, causes tides in oceans
4. Free Fall
When an object falls towards the Earth only under the influence of gravity, it is called free fall.
During free fall:
acceleration is constant
air resistance is neglected
5. Acceleration due to Gravity (g)
The acceleration produced in a freely falling body due to Earth’s gravity is called acceleration
due to gravity.
Symbol: g
Value near Earth’s surface: 9.8 m/s²
6. Relation Between g and G
𝑮𝑴
𝑹𝟐
Where:
G = universal gravitational constant
M = mass of the Earth
R = radius of the Earth
7. Mass
Mass is the quantity of matter contained in an object.
Properties:
1. Gravitation
Gravitation is the force of attraction between any two objects having mass.
This force:
keeps planets in their orbits
causes objects to fall towards the Earth
is present between all bodies in the universe
2. Universal Law of Gravitation
Every object in the universe attracts every other object with a force that:
is directly proportional to the product of their masses
is inversely proportional to the square of the distance between their centres
Mathematical Form:
𝒎𝟏 𝒎𝟐
F= G
𝒓𝟐
Where:
F = gravitational force
G = universal gravitational constant
m₁, m₂ = masses of the two objects
r = distance between their centers
3. Importance of Gravitation
Gravitation:
binds objects to the Earth
keeps the Moon around the Earth
keeps planets around the Sun
, causes tides in oceans
4. Free Fall
When an object falls towards the Earth only under the influence of gravity, it is called free fall.
During free fall:
acceleration is constant
air resistance is neglected
5. Acceleration due to Gravity (g)
The acceleration produced in a freely falling body due to Earth’s gravity is called acceleration
due to gravity.
Symbol: g
Value near Earth’s surface: 9.8 m/s²
6. Relation Between g and G
𝑮𝑴
𝑹𝟐
Where:
G = universal gravitational constant
M = mass of the Earth
R = radius of the Earth
7. Mass
Mass is the quantity of matter contained in an object.
Properties:
