Acceleration due to gravity is found to decrease with increase in depth and vice versa. But, on the poles its value is more than as compared to that on the equator even though the depth is increasing.Why is this so? I know about the relation g is inversely proportional to R squared, but without this relation I can’t seem to b able to answer it with the depth relation.
Asked Thakrei Ruivah
The force of gravity is inversely proportional to the the distance from the centre of earth and hence it is evident that at poles the acceleration due to gravity should be more since the polar radius is less that the equatorial radius.
Putting it simply, the entire mass of earth is attracting the object kept at the pole towards it centre and the distance from the centre is less. Therefore the force and hence the acceleration due to gravity will be maximum.
The decrease in g with depth is due to the fact that:
At any depth, the mass of earth coming within the sphere with radius equal to the distance from the centre of earth to the object under consideration will be responsible for the force of gravity and hence the value of acceleration due to gravity decreases.
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