Toronto Math Forum

APM346-2015S => APM346--Home Assignments => HA8 => Topic started by: Chaojie Li on March 19, 2015, 09:13:07 PM

Title: Solution of Question 4
Post by: Chaojie Li on March 19, 2015, 09:13:07 PM

Using Newton shell theorem (see [Section 6 of Lecture 25]) prove that if Earth was a homogeneous solid ball then the gravity pull inside of it would be proportional to the distance to the center.

Title: Re: Solution of Question 4
Post by: Chaojie Li on March 19, 2015, 09:14:32 PM

Q4 reloading

Title: Re: Solution of Question 4
Post by: Victor Ivrii on March 20, 2015, 08:17:36 AM

Yes exactly: if you drill a tunnel and drop a ball it will be a harmonic oscillations $r'' = - kr $ with $k= g/R$.

Don't try this at home on our planet! :D