This is #32 on the GRE practice exam from www.gre.org.(adsbygoogle = window.adsbygoogle || []).push({});

Three equal masses m are rigidly connected to each other by massless rods of length l forming an equilateral triangle, as shown above. The assembly is to be given an angular velocity w about an axis perpendicular to the triangle. For fixed w, the ratio of the kinetic energy of the assembly for an axis through B compared with that for an axis through A is equal to

[A is located at the center of the triangle, B is located at a corner of the triangle]

a. 3

b. 2

c. 1

d. 1/2

e. 1/3

The answer is B, but I get 3 for an answer.

This is an easy problem, but for some reason I don't know why I am not getting it. Can someone else work this out and tell me if you get the right answer, and how you arrive at it?

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# Homework Help: Kinetic Energy Problem - from GRE

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