Do you weigh differently at the North Pole than what you do at the equator?


Yes you do, because at the equator the centrifugal force due to the spinning of the Earth is at its maximum, and vanishes at the poles. This means that the attractive force of gravity is slightly reduced because it is directed towards the center of the Earth, while the centripetal force is directed outward from the center. The effective acceleration of gravity at the poles is 980.665 cm/sec/sec while at the equator it is 3.39 cm/sec/sec less due to the centrifugal force. If you weighed 100 pounds at the north pole on a spring scale, at the equator you would weigh 99.65 pounds, or 5.5 ounces less. Your mass, in grams, however would stay the same because 'grams' is a measure of the resistance of a body to being moved and has nothing to do with acceleration or gravity. Your mass in kilograms would remain the same. It is common for people to use 'pounds' and 'grams' interchangeably but they are not.


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All answers are provided by Dr. Sten Odenwald (Raytheon STX) for the
NASA IMAGE/POETRY Education and Public Outreach program.