We know that the force of gravity varies from place to place on the surface of earth.
| There are two reasons behind this variation: | ||||||||||
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The shape of earth.
The rotation of earth. |
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| The earth is not a perfect sphere, but bulges at equator. Therefore if a body is taken from pole to equator its distance from the centre of the earth will change. Consequently,the gravitational force also varies. | ||||||||||
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VARIATION
OF g WITH ALTITUDE
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| Consider the variation of g when a body moves distance upward or downward from the surface of earth. | ||||||||||
| Let
g be the value of acceleration due to gravity at the surface of
earth and g' at a height h above the surface of earth. If the earth is considered as a sphere of homogeneous composition, then g at any point on the surface of the earth is given by: |
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| This expression indicates that the acceleration due to gravity decreases with altitude. | ||||||||||
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