Register to reply

Center of Mass

by ticklemepink20
Tags: mass
Share this thread:
Dec11-06, 12:52 PM
P: 1
[b]1. A composite slab has dimensions of d1=11.0cm, d2=2.80cm, and d3=13.0cm. Half the slab consists of aluminum (density=2.70g/cm^3) and half consists of iron (density=7.85g/cm^3). What are the x coordinate, y coordinate, and z coordinate of the slab's center of mass?

There's a figure in my book where the dimensions are for each the iron and aluminum. In other words, if you find the volume using the dimensions they give you, if you double it you have the volume for the whole figure.

I have no idea where to even begin.
I found the volume for each piece to be 400.4g

I tried finding the mass for each using p=m/v.
For the aluminum I got m=(400.4cm^3)(2.70g/cm^3) = 1081.08g
For the iron I got m=(400.4cm^3)(7.85g/cm^3) = 3143.17g

No clue how to find x, y, and please!!
Phys.Org News Partner Science news on
Experts defend operational earthquake forecasting, counter critiques
EU urged to convert TV frequencies to mobile broadband
Sierra Nevada freshwater runoff could drop 26 percent by 2100
Dec11-06, 01:01 PM
Sci Advisor
HW Helper
P: 3,031
If you are saying that each metal is a rectangle 11cm x 13cm with a thickness of 2.8cm stacked to make a total thickness of 5.6cm, then by symmetry the CM position is on a line through the centers of the big ractangular faces. You just need to find the position along the direction of the 5.6cm thickness. You can do that by using the mass and the CM positions of the individual metals.

Register to reply

Related Discussions
Center of gravity (it's not center of mass ) General Physics 28
The geometric center of the Earth and the center of mass Classical Physics 9
Can two objects with the same center of mass oscillate about that center? Introductory Physics Homework 0
Help with problem of Center of mass, linear mass density and total mass Introductory Physics Homework 1
The center of Mass perfectly match the center of Force-> General Physics 9