1. The problem statement, all variables and given/known data In Fig. 9-39, three uniform thin rods, each of length L = 28 cm, form an inverted U. The vertical rods each have a mass of 12 g; the horizontal rod has a mass of 31 g. What are (a) the x coordinate and (b) the y coordinate of the system's center of mass? (Give your answer in cm) http://edugen.wiley.com/edugen/courses/crs1650/art/qb/qu/c09/fig09_37.gif 2. Relevant equations xcom = (m1x1 + m2x2)/M 3. The attempt at a solution I got the x coordinate alright at 14cm but I can't find the y coordinate. I took the center of mass between the two vertical rods with y1 = 14cm and its m1 = 24g as total of the vertical rods. I then compared that center of mass to the center of mass of the horizontal rod with y2 = 28cm and its m2 = 31g. I thus found y = 21.89, but this is apparently wrong, could somebody please tell me what it is that I'm doing wrong?