Gravitation

[Avirup-Croocked Scientist]

Hello friends,

I would appreciate your thankful help in solving this problem on gravitation from an IIT practice paper:-

A tunnel is dug in the earth across one of its diameter. Two masses m and 2m are dropped from the ends of the tunnel. The masses collide and stick to each other and perform SHM. Then amplitude of SHM will be (when R=radius of the earth)

(a) R (b) R/2 © R/root3 (d) 2R/3.

I will be pleased if anyone writes the concept used and explains the steps briefly........ a fresher to the `SFN` looking forward to a reply soon.

Thanking You

[mathematic]

What are SHM and SFN?

[D H]

SHM = simple harmonic motion.

SFN = ScienceForums.net

 

 

Avirup-Croocked Scientist, what work have you done on this problem? This is essentially a homework problem. You need to show some work before we can help you.

[DrRocket]

Hello friends,

I would appreciate your thankful help in solving this problem on gravitation from an IIT practice paper:-

A tunnel is dug in the earth across one of its diameter. Two masses m and 2m are dropped from the ends of the tunnel. The masses collide and stick to each other and perform SHM. Then amplitude of SHM will be (when R=radius of the earth)

(a) R (b) R/2 © R/root3 (d) 2R/3.

I will be pleased if anyone writes the concept used and explains the steps briefly........ a fresher to the `SFN` looking forward to a reply soon.

Thanking You

 

Concepts to be used:

 

1) Newtonian gravity [math] F=G \frac {m_1m_2}{r^2}[/math]

 

2) Classical Newtonian mechanics [math]F=ma[/math]

 

But as DH said, you need to show some work and a reasonable attempt to use these principles.

[elfmotat]

Are you familiar with Gauss' Law for electric fields? There's also a Gauss' law for gravitational fields:

 

[math]\oint\boldsymbol{g}\cdot d\boldsymbol{A}=-4\pi GM[/math]

 

**Hint: In a typical E&M class you'll eventually be asked to solve for the electric field in the interior of a sphere with constant charge density (E as a function of the distance from the center).

Edited February 14, 2012 by elfmotat