Gravitation is a universal force acting between all objects with mass or energy, governed by Newton's law of universal gravitation, which states that the force is proportional to the product of their masses and inversely proportional to the distance squared. Key concepts include the role of gravitons as hypothetical particles of gravity, the elliptical orbits of planets described by Kepler's laws, and the distinction between mass and weight, with weight varying based on location. Additionally, gravitational potential energy and escape velocity are important aspects of the force of gravity.

1. GRAVITATION

2. WHAT IS
GRAVITATION ?
• Gravitational force is a universal force and it
acts not only between two objects on the
earth but also between any two objects in the
universe.
• Gravitation is a natural phenomenon by
which all things with mass or energy—
including planets, stars, galaxies, and even
light—are brought toward (or gravitate
toward) one another.

3. LAW OF GRAVITATION
• Newton's law of
universal gravitation states that every
particle attracts every other particle in
the universe with a force which is
directly proportional to the product of
their masses and inversely proportional
to the square of the distance between
their centers.
•F=G m1m2/d2

4. GRAVITONS
• Basic particles of Gravity.
• Yet to be discovered
• In theories of quantum gravity,
the graviton is the hypothetical quantum of
gravity, an elementary particle that mediates
the force of gravity.

6. CIRCULAR MOTION &
CENTRIPETAL FORCE

7. KEPLER’S LAW
• The orbit of a planet is an ellipse with
the Sun at one of the foci.
• The line joining the planet and the Sun
sweeps equal areas in equal intervals
of time.
• The square of its period of revolution
around the Sun is directly proportional
to the cube of the semi major axis of a
planet from the Sun.

8. 1ST LAW

9. 2ND LAW

10. 3RD LAW

11. EARTH’S
GRAVITATIONAL
ACCELERATION
• Standard value is 9.807 m/s2
• Change along the surface of Earth.
• Change along variation in height.
• Change along depth.
• g=GM/r2

12. MASS VS WEIGHT
MASS
• Amount of matter
present in the
object.
• Value is same
everywhere.
• It is a scalar
quantity.
WEIGHT
• The force with which
the earth attracts the
object.
• Value changes with
respect to place on
Earth.
(F=W=ma=mg).
• It is a vector quantity
directed towards the
centre if Earth.

13. FREE FALL
• When an object moves under the
influence of the force of gravity alone, it
is said to be falling freely.
• But its not a true free fall, since motion
is opposed by friction with air.
• Terminal velocity.

14. GRAVITATIONAL
POTENTIAL
• The energy stored in an object because of its
position or state is called potential energy.
• For an object of mass m, at a height h from
the ground is mgh and on the ground it is
zero.
• For large value of h, value of g decreases
with increase in h.
• Gravitational potential energy is given by “-
GMm/(R=h)

15. ESCAPE VELOCITY
• Escape velocity is the minimum speed
needed for a free object to escape from
the gravitational influence of a massive
body.

16. THANK YOU