----- Original Message ----- From: "Robert Everland" <[EMAIL PROTECTED]> To: "CF-Community" <[EMAIL PROTECTED]> Sent: Tuesday, September 10, 2002 1:19 PM Subject: RE: Hole in the Earth?
> Gravity at the Earth's Center > (Two questions with the same answer) > (1) My students had a couple of questions that I thought were interesting. I > told them I'd ask ya'll. > > What would you weigh is you were at the exact center of the earth? > Essentially, it would be zero (neglecting the fact that the Earth is not a perfect sphere and the forces of gravity from other celestial bodies). > What would you weigh is you were 3 meters from the center of the earth? Essentially zero. It would be the same as your wieght if you were on a planet that had a radius of 3 meters. > Please include supporting evidence for your answers > Evidence, I don't need no stinkin' evidence :-) It's basic laws of physics... > (2) > > I am confused about Newton's discussion of the force on a particle within a > sphere in the Principia. In one place, he says that the force would be zero, > since the attraction of all the particles in the sphere would cancel each > other out. Yep, true. > Just a little further on, he says that the force would be directly > proportional to the particle's distance from the center of the sphere. > Also true. > Can you clarify these two seemingly conflicting statements? > They are not conflicting. In the center of a spherical mass the effects of gravity from the mass are cancelled out. If you venture from the center of the mass then the gravity is related to the distance from the center. > Thank you for any light that you can shed. > > Regards, Howie ______________________________________________________________________ This list and all House of Fusion resources hosted by CFHosting.com. The place for dependable ColdFusion Hosting. Archives: http://www.mail-archive.com/[email protected]/ Unsubscribe: http://www.houseoffusion.com/index.cfm?sidebar=lists
