Variation of g-variation of acceleration due to gravity
We know that the force of gravity varies from place to place on the surface of earth.
There are two reasons behind this variation:
- The shape of earth.
- The rotation of earth.
The earth is not a perfect sphere, but bulges at the equator. Therefore, if a body is taken from pole to the equator its distance from the centre of the earth will change. Consequently, the gravitational force also varies.
Variation of g with altitude
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:
This expression indicates that the acceleration due to gravity decreases with altitude.
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