# Homework Help: Engineering Statics Center of Gravity Problem

1. Apr 18, 2010

### ttran1117

1. The problem statement, all variables and given/known data
For the machine element shown, locate the x coordinate of the center of gravity.
The picture of 2 different problems are attached

2. Relevant equations
V = 1/3*a*b*h

3. The attempt at a solution
I can figure out the coordinates fine for everything except the triangles. I looked at the solution for problem 96 and I can't seem to figure out why the solution is 2/3*66 + 34 (coordinate). I understand that the base would be x/3, or 66/3, which is true for problem 98, so why isnt it problem 96 using 34+ 1/3*66 and instead is using 34 +2/3*66? Any help would be greatly appreciated, as I have spent a long time on this and can't seem to figure it out. Also, would this be same for the y component as well? Thank you very much

#### Attached Files:

File size:
90.3 KB
Views:
136
• ###### Prob05098.pdf
File size:
83.6 KB
Views:
82
Last edited: Apr 18, 2010
2. Apr 18, 2010

### pongo38

I think the triangle you speak of is the 'empty' triangle in the xz plane. What is the x-coordinate of its centre of gravity? To check this, draw a plan of the triangle and obtain the position of G by joining the mid point of each side to its opposite corner. Hopefully this is enough for the penny to drop.