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three uniform disks of the same mass per unit area, and radii a, 2a, 3a are placed in contact with each other with their centers on a straight line. how far is the center of mass of the system from the center of the smallest disk?

solution:

m1=pi a^2

m2=4pi a^2

m3=9pi a^2

Xc = (m1/mtotal)Xo + (m2/mtotal)(Xo+3a)+(m3/mtotal)(Xo+8a)

Xc = 1/14Xo + 4/14Xo + 6/7a + 9/14Xo + 72/14a

Xc = Xo + 6a

therefore center of mass of system is 6a from the center of the smallest disk.

is this correct?

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# Homework Help: Mass center problem

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