# Help with centre of mass please

1. May 2, 2006

### dirac1

http://i3.tinypic.com/wmjdqh.jpg

its question number 10

hi all i was wondering if you could help me with my centre off mass question sthanks

the diagram shows a thing uniform sqaure of metal which has a corner folded over. Calculate the distance the centre of mass of ABCDEF is from A

thanks you

2. May 2, 2006

### Staff: Mentor

So what techniques do you use to calculate the center of mass of an object? You need to show us how you are starting to solve the problem....

3. May 2, 2006

### dirac1

i used or tried centr mass of triangle =1/3 height and 1/3 width i then used centre mass of square is 1/2 base and 1/2 height.

i then took the triangle away from the sqaure a little like this

centre of mass of triangle
x=4+4/3=5 and 1/3
y=4+4/3=5 and 1/3

centre of mass of sqaure =
x=4
y=4

mass of square - 8x8=64
mass of triangle - 4x4=16

i tried distance between two points is [(x1-x2)^2+(y1-y2)^2)]^0.5

but it didnt work :(

just wondered where im going wrong

4. May 2, 2006

### Hootenanny

Staff Emeritus
You may want to check the x distance for your COM of the triangle. And also the mass of your triangle.

~H

Last edited: May 2, 2006
5. May 2, 2006

### dirac1

thyanks buddy i got it now