# Center of mass

1. Oct 11, 2008

### shirel

Hi!

I'm very curious to know how the Center of mass, that I know from Math is relevant for the physics' subjects.

I know already how it affects stars, but I'm interested to know how it is being used in electricity, magnetism, mechanics and other stuff on EARTH :tongue2:

Therefore, I refer to 3D shapes and not 2D.

Thank you very much!

2. Oct 11, 2008

### Staff: Mentor

Start here: http://en.wikipedia.org/wiki/Center_of_mass" [Broken]

Last edited by a moderator: May 3, 2017
3. Oct 12, 2008

### Naty1

Center of mass isn't generally used for subatomic interactions describing electricity or magnetism. electrons or fields are the common description vehicles.

Center of mass is widely used in the study of statics and dynamics, for example rotating bodies or forces exerted by beams. If you know the center of mass of a steel beam for example, usually the venter of it's length it becomes very easy to calculate it's torque (twist) about some fixed point....Torque = weight (at the center of mass) times the distance ( from the center of mass to the point at which torque is measured)...

4. Oct 12, 2008

### shirel

Thank you both very much!
I'm still waiting for more ideas :)

5. Oct 12, 2008

### Naty1

When ideal bodies interact, say a pair of billard balls, the momentum of the balls combined center of mass before they collide equals that after the collision....

A related reaction is FT =MV..force applied x time equals mass x velocity....

Try Wikipedia for things like conservation of momentum, of angular momentum, elastic collisions....also search statics or static forces....

6. Oct 12, 2008

### shirel

Ohh I liked this idea, thanks :)