I remember reading that people are actually lighter when they are at high altitudes, and the main reason given is "greater distance from center of mass of the Earth" (inverse square law, and all, dontchaknow?), but wouldn't part of the effect be due to an equivalently increased centripetal force from planetary rotation? The higher you are above sea level, the greater the radius of rotation that point would have to go through in any given 24-hour period.
It is similar to the old math puzzle where you are given a length of string long enough to circle the equator, and then asked how much more string you would have to have tied onto the end to be able to suspend the string exactly one foot above the surface, all the way around the roughly 25,000 mile long equator. (Hint: Unless you know the answer, you WILL overestimate the amount needed.)
Answer: Highlight here if you want to know -- roughly 6' 3-1/2". The reason is because the 25,000 miles is around a planet with a diameter of roughly 8,000 miles, using the C=pi*D (circumference = diameter times 3.141592653+ ), and adding a foot above the equator is only adding two feet to the diameter, and 2 x 3.141592653 = 6.283185306+, or roughly 75 1/2". I'm taller than that. End of answer.
Anyhow, for every foot above sea level you get, you will be traveling that extra distance every 24 hours (added onto the roughly 1,050 mph the people on the equator are already doing -- 25,000 miles every 24 hours), and the slight extra lift they get would make them weight just a trifle less.
Not so?
2 comments:
Makes perfect sense: except it's centriFUGAL force, isn't it
I know one is supposed to be the force drawing TOWARDS the center of rotation (centripetal) and the other pulls away from it (centrifugal), but since we are measuring the force pulling down to the center of rotation (making things lighter), it would still be "centripetal".
It is the increased centrifugal force being exerted that reduces the centripetal force being measured...
So YMMV ;)
Post a Comment