Physics XI Content
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: | |||
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| 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: | |||
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| This expression indicates that the acceleration due to gravity decreases with altitude. | |||