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GRAVITATION

The term "Gravitation" refers to, the force of
attraction between any two bodies of the
universe
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NEWTON'S UNIERSAL LAW OF
GRAVITATION

Long before Sir Isaac Newton realised that
the same force that caused an apple to fall at
the Earth's surface—gravity—was also
responsible for holding the Moon in orbit
about the Earth
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And the direction of the force
is along the line joing the masses
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F=GMm/R^2
Here, G is universal gravitational constant
and its value is 6
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ACCELERATION DUE TO
GRAVITY

The acceleration produced in any body due
to gravity is known as Acceleration due to

Gravity
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The value of g varies from one celestial
body to another
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Therefore, our weight would be different on
the Moon from that of the Earth
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8m/s^2
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62519 m/s^2 about 16
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Relation between G and g
M=mass of the earth
m=mass of the body
R=radius of the earth
G=universal gravitational constant
As we know that F=GMm/R^2

Again,
(or)

F=ma
F=mg


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(2)

from eqn (1) and (2), we get-

mg=GM/R^2
g=GM/R^2

Hence, we can conclude that g depends upon
the mass of the earth and it doesn't depends
upon the mass of the body
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Which object - the ball or the
feather - will hit the ground first? Think
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As they both will experience
the same force of gravity
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VARIATION IN VALUE OF 'g'
◆ The value of acceleration due to gravity
decreases with increase in height above the
surface of the Earth
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◆ The value of acceleration due to garvity
equals to zero at the centre of the earth
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It's value is maximum at the poles
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Escape velocity is defined to be the
minimum velocity an object must have in
order to escape the gravitational field of the
earth, that is, escape the earth without ever
falling back
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186 km/s (6
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For calculating escape velocity the formula
used is-



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