Gravitation
Gravitation is the form of attraction b/w any two bodies in the universe due to masses of the
bodies called Gravitation. The applied force is gravitation force.
It's weakest force in the all-fundamental forces.
Range of this force infinite but the effect becomes weaker as the object moves away.
All the object in the universe attracts each other with a certain amount of force, but in most
cases, the force weak to be observed due to the very large distance of separation.
1
Distance ∝ Graviation
Gravitation ∝mass
Gravity – Earth attracts everything towards It by a seen force of attraction. This force is
called Gravity
Some e.g.:
1. The force that causes the ball to come down is known as gravity.
2. Gravity keeps the planets orbit around the sun.
3. Gravity is the force that causesa rock to roll downhill.
Note: Object fall towards the earth when released from height due to gravity.
Universal law of Gravitation
According to it:- Everybody in the universe attract every other body with a force which
directly proportional to the product of their masses and inverselyproportional to the square of
the distance b/w them.
This law is given by Newton.
F X m1 x m2-(1)
FX 1 -(2)
D^2
F= G m1 x m2
D^2
When G= universal contact or gravitation contact.
The formula of Gravitational force
S.I unit=N (Newton)
Note- The force of gravitation is a vector quantity."
F= G m1 x m2
D^2
So,
SI unit =nm^2
, Kg^2
Value = 6.67×10^-11 nm^/kg^2
Why G is called universal constant?
As value of G remains constant throughout the universe which its value does not change with
place, height, etc.
That’s why to called universal constant.
Note! Gis numerically equal to the force of gravitation which exists b/w two bodies of unit
mass kept at unit distance from each other.
Note: Though the various objectsan earth attract one another. Constantly they do not cause
motion because the gravitational force of attraction b/w then very When both the object is
very big having very large masses, then the gravitational extremely large.
Free Fall
When an object falls from any height under the influence of gravitation. Force only it's
known as free fall.
In this case direction no change.
Velocity change because of acceleration.
Free fall not depends on Mass.
Free fall depend of fall on the size &period of fall.
Acceleration due to gravity
The acceleration of a freely falling body due to gravitational force of earth.
Let mass of object (mo) freely fall on earth due to gravity, h is the height o object from earth
surface and Re is the radius of earth, so acceleration due to gravity on the object is.
w.k.t, F =Gm1Xm2
(Re+h)^2
So, g=G Ma
(Re)^2
be this formula we say that acceleration due to gravity is independent to mass of object.
When an object is near to surface of earth, distance b/w object and centre of the earth will be
equal to the radius of earth.
g = Gma
(Re)^2
Value of g various at pole & equator Because earth is not a perfect circle. Hence it's radius
change due to which value of g also change.
↓↑ g X 1↓↑
h
Gravitation is the form of attraction b/w any two bodies in the universe due to masses of the
bodies called Gravitation. The applied force is gravitation force.
It's weakest force in the all-fundamental forces.
Range of this force infinite but the effect becomes weaker as the object moves away.
All the object in the universe attracts each other with a certain amount of force, but in most
cases, the force weak to be observed due to the very large distance of separation.
1
Distance ∝ Graviation
Gravitation ∝mass
Gravity – Earth attracts everything towards It by a seen force of attraction. This force is
called Gravity
Some e.g.:
1. The force that causes the ball to come down is known as gravity.
2. Gravity keeps the planets orbit around the sun.
3. Gravity is the force that causesa rock to roll downhill.
Note: Object fall towards the earth when released from height due to gravity.
Universal law of Gravitation
According to it:- Everybody in the universe attract every other body with a force which
directly proportional to the product of their masses and inverselyproportional to the square of
the distance b/w them.
This law is given by Newton.
F X m1 x m2-(1)
FX 1 -(2)
D^2
F= G m1 x m2
D^2
When G= universal contact or gravitation contact.
The formula of Gravitational force
S.I unit=N (Newton)
Note- The force of gravitation is a vector quantity."
F= G m1 x m2
D^2
So,
SI unit =nm^2
, Kg^2
Value = 6.67×10^-11 nm^/kg^2
Why G is called universal constant?
As value of G remains constant throughout the universe which its value does not change with
place, height, etc.
That’s why to called universal constant.
Note! Gis numerically equal to the force of gravitation which exists b/w two bodies of unit
mass kept at unit distance from each other.
Note: Though the various objectsan earth attract one another. Constantly they do not cause
motion because the gravitational force of attraction b/w then very When both the object is
very big having very large masses, then the gravitational extremely large.
Free Fall
When an object falls from any height under the influence of gravitation. Force only it's
known as free fall.
In this case direction no change.
Velocity change because of acceleration.
Free fall not depends on Mass.
Free fall depend of fall on the size &period of fall.
Acceleration due to gravity
The acceleration of a freely falling body due to gravitational force of earth.
Let mass of object (mo) freely fall on earth due to gravity, h is the height o object from earth
surface and Re is the radius of earth, so acceleration due to gravity on the object is.
w.k.t, F =Gm1Xm2
(Re+h)^2
So, g=G Ma
(Re)^2
be this formula we say that acceleration due to gravity is independent to mass of object.
When an object is near to surface of earth, distance b/w object and centre of the earth will be
equal to the radius of earth.
g = Gma
(Re)^2
Value of g various at pole & equator Because earth is not a perfect circle. Hence it's radius
change due to which value of g also change.
↓↑ g X 1↓↑
h
