On 28.03.2010, at 06:48, Edward Cherlin wrote: > > On Sat, Mar 27, 2010 at 23:11, Yamandu Ploskonka <yamap...@gmail.com> wrote: >> How much lighter is a person in La Paz, Bolivia, than at sea level? >> This actually was asked by a kid when I was there last time. >> For practical purposes let's assume La Paz is 3.800 m over sea level > > Fascinating question. The simplest answer is that weight is inversely > proportional to distance from the center, which we can approximate as > 40,000 km/pi, or 12,742 km on average. This would give us a difference > of roughly one part in 5,000 in weight for a difference of 4 parts in > 10,000 in height. > > However, the distance between surface and center is actually 43 km > greater at the equator than at the pole, so we have to do some much > finer calculations to locate sea level at he latitude of La Paz. Then > we have to decide whether to ask what the weights would be on a > stationary Earth, or whether we will take rotation into account, > resulting in apparent decreases in centripetal forces. If we wanted to > be really finicky, we could take relativity into account also. ^_^
Indeed. My 10 year old son came home recently with the claim that people on mountains live longer. We had some fun introducing relativity, but didn't actually bother to calculate what fraction of a second this would amount to over a lifetime ;) - Bert - _______________________________________________ IAEP -- It's An Education Project (not a laptop project!) IAEP@lists.sugarlabs.org http://lists.sugarlabs.org/listinfo/iaep
