# Gravitational force at equator

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#1
So I don't know but I'm really not understanding some stuff.Firstly, we know that the for anything orbiting the Earth, the centripetal force is provided by the gravitational force of the Earth.And we use mv²/r = GMm/r² .However, we know that at the poles, the Centripetal force is zero? Is it true?And what about equator? Why is value of g less at the equator? And how can we show it mathematically? Does centripetal force increase at equator?
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3 weeks ago
#2
(Original post by Knightrises10)
So I don't know but I'm really not understanding some stuff.Firstly, we know that the for anything orbiting the Earth, the centripetal force is provided by the gravitational force of the Earth.And we use mv²/r = GMm/r² .However, we know that at the poles, the Centripetal force is zero? Is it true?And what about equator? Why is value of g less at the equator? And how can we show it mathematically? Does centripetal force increase at equator?
Might want to double check this, but:

The point of rotation of the earth is at the poles. So at the poles the distance/radius from the point of rotation, r, is zero, so insert that in the formula for F=mv²/r, therefore the centripetal force is zero.

Basically the earth isn't perfectly spherical, (Imagine you hold the earth in your hands at the poles, and apply pressure, the plane along the equator is bulged out - so you can picture that in your head) so the equator is slightly further out from the point of rotation (which is the poles)
Since r would be slightly more from the centre of the earth, you experience less force, therefore weigh less.

Hope this helps 0
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