# Center of Mass Question!

1. Mar 9, 2013

### dgx

1. The coordinates of the center of mass for the extended object shown in the figure are (L/4, −L/5). What are the coordinates of m1? (Assume m1 = 7 kg, m2 = 3 kg, and m3 = 5 kg. Use any variable or symbol stated above as necessary.)

2.

3. I too the centroid cordinates and substracted them from each corresponding x and y value in each coordinate. Then, distributed the mass to each corresponding coordinate...ie 7(x,y) = (7x,7y), then solved for x and y. My answer was (L/7, -21L/10). But its wrong. Anybody have any insight?

2. Mar 9, 2013

### ap123

Hello dgx!
Can you upload the diagram for us?

3. Mar 9, 2013

### dgx

http://www.tiikoni.com/tis/view/?id=b95408f [Broken]

http://www.tiikoni.com/tis/view/?id=b95408f [Broken]

thanks

Last edited by a moderator: May 6, 2017
4. Mar 9, 2013

### ap123

Use the definition of the centre of mass.
You will get 1 equation for the x-direction and 1 for the y-direction.
Each of these equations will only have 1 unknown.

If you post your working we can see what you did.