Help finding mass and center of mass?

Center of mass physics problem help?

• Four very thin rods, each 8.0 m long, are joined to form a square, as part (a) of the drawing shows. The center of mass of the square is located at the coordinate origin. The rod on the right is then removed, as shown in part (b) of the drawing. What are the x- and y-coordinates of the center of mass of the remaining three-rod system? It's a square with the right vertical side removed so it makes a sort of square C shape. I figure the right side now has 8 mass and the left side has 16 mass. 16-8=8 8/3=1.6 But this is not right. I don't understand how to put in the x-coordinates of sticks that are parallel to the x-axis. Please help!!!

• Answer:

  You need to find the centroids by equation. The y value will remain the same but the 'x' can be calculated as follows: x_system = (x_north * L + x_west * L + x_south * L ) / (L + L + L) x_system = (0 + -4 + 0)/3 = -4/3 from the centroid of the open square