In: Physics
A 80 kg man weighs himself at the north pole and at the equator. Which scale reading is higher? (The radius of the earth at the equator is 6.37 x 106m). By how much? ____N
The two reasons (centripetal acceleration and less g due to
increased radius at the equator) have been given in the answers
above, but only one answer referred to both of them, and then only
suggested that it was one or the other. Well it's the combined
effect of the two that reduces your equatorial weight. And (this
shouldn't be too surprising) the reason Earth's equatorial radius
is greater than its polar radius is in fact centripetal
acceleration applied to the earth itself. Earth's huge size causes
the solid materials like rock that it's made of, that are rigid on
a smaller scale, to behave more like a thick liquid and be
distorted in the direction of the centripetal acceleration.
Note that you won't see your weight difference on a weight-balance
type scale, since those weights are subject to the same centripetal
and gravitational accelerations as you are. Only a spring-based
scale can measure these differences.