- #1

raptik

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## Homework Statement

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

## Homework Equations

x

_{com}= (m

_{1}x

_{1}+ m

_{2}x

_{2})/M

## 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 y

_{1}= 14cm and its m

_{1}= 24g as total of the vertical rods. I then compared that center of mass to the center of mass of the horizontal rod with y

_{2}= 28cm and its m

_{2}= 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?