A man of mass m standing at the North or South Pole is quite literally spinning on the spot. A man standing at the equator is moving acound the centre of the Earth at about 460 m/s or almost half a kilometer per second.
This means that a man standing on the equator is experiencing a centrifugal force equal to
as a result of his motion around the centre of the Earth (the speed of the man on the equator around the centre of the Earth is
). Whether the man is on the equator or at the pole, assuming the distance towards the centre of the Earth is the same and equal to
he will experience the force of gravity
where
and
is the mass of the Earth.
The difference between the two forces is small and reduces the weight of the man on the Equator slightly. If the man has a mass or 80 Kg, his weight at the pole will be
but his weight at the equator will be reduced by