Kodo Millet PPT made by Ghanshyam bairwa college of Agriculture kumher bhara...
Gravitation
1.
2. • Definition for Gravitation
• Acceleration Due to Gravity
• Variation Of “G” With Respect to Height And Depth
• Escape Velocity
• Orbital Velocity
• Gravitational Potential
• Time period of a Satellite
• Height of Satellite
• Binding Energy
• Various Types of Satellite
• Kepler’s Law of Planetary motion
3. 1.Gravitation is a natural Phenomenon by
which physical bodies attract each other.
2.Newton focused his attention on the
motion of the moon about the earth.
3.He declared that the laws of nature that
operating between earth and the apple is
same as the laws of operating between
earth and moon.
4.He calculated the acceleration due to
gravitation(on earth) to be 9.8 m/s2
4.
5. • The rotation of the earth around the sun or
that of the moon around earth is explained
on the basis of this law.
• The tide are formed in ocean due to the
gravitational
force of attraction between earth and the
moon.
• The value of g can be used to predict the
orbits and time
period of an satellite.
Attraction Force between two bodies
6. • The Gravitation force between two masses
is independent
of the intervening medium.
• The mutual gravitational forces between two
bodies are
equal and opposite i.e. Gravitational Forces
obey Newton’s third law of motion.
• The gravitational force is an conservative
force.
• The law of gravitation holds only for point
masses.
• The gravitational force between two point
masses is a
central force. Its magnitude depends only
on r and has no angular dependence .
• The Gravitational force between two bodies
is independent of the presence of other
bodies.
7.
8.
9.
10. The Variation of g with respect to
Depth and Height (graph).
The Variation of g with respect to
height will never be zero. It will increase
after certain height.
The Variation of g with respect to depth
will be zero when the body is placed at
the center of earth.
11.
12. Gravitational field
• Gravitational field . Two bodies attract each
other by the gravitational force even if they
are not in direct contact. This interaction is
called action at a distance. It can best
explained in terms of concept of field.
According to the field concept.
– Every mass modifies the space around it . This
modified space is called gravitational field
– When any other mass is placed in this field , it feels a
gravitational force of attraction due to its interaction
with the gravitational field
• The space surrounding a material body
within which its gravitational force of
attraction can be experiences a force of
attraction towards the centre of earth
15. • If we throw a ball into air , it rises to a certain
height and falls back. If we throw it with a
greater velocity , it will rise higher before
falling down. If we throw with sufficient
velocity , it will never come back . i.e. It will
escape from the gravitational pull of the earth
• The minimum velocity required to do so is
called escape velocity.
• Consider the earth to be a sphere of mass M
and radius R with centre O.
16.
17.
18. • Law of orbits (first law) : Each planet
revolves around the sun in an elliptical
orbit with the sun situated at the one of
the two foci.
19. • Law of areas (second law) : The radius
vector drawn from the sun to a planet
sweeps out equal areas in equal intervals
of time i.e the areal velocity ( area
covered per unit time) of a planet around
the sun is constant.
