# Homework Help: Center of mass of three beads

1. Oct 27, 2014

### starJ9

• OP warned about not including an attempt at a solution
1. The problem statement, all variables and given/known data

Three beads are placed on the vertices of an equilateral triangle of side d = 1.8 cm. The first bead of mass m1 = 150 g is placed on the top vertex. The second bead of mass m2 = 55 g is placed on the left vertex. The third bead of mass m3 = 85 g is placed on the right vertex.

Write a symbolic equation for the horizontal position of the center of mass relative to the left vertex of the triangle.

2. Relevant equations

xcm = m1x + m2x + m3x...+mnxn / Mn

3. The attempt at a solution

2. Oct 27, 2014

### BvU

Hello star! Welcome to PF. :)
Good start, this equation. Since we are dealing with three masses, you can stop at 3. But we are also dealing with two dimensions, so we need something similar for the y coordinate. And I think I am missing some brackets -- at least if $M_n = \Sigma_i m_i$

Furthermore, PF rules dictate that you show an actual attempt at solution (otherwise we would be in trouble with all teachers all over the place). No problem in your case: just fill in some numbers to see what you get !