VARIATION OF g -VARIATION OF ACCELERATION DUE TO GRAVITY

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 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.
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.