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?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Kinetic Energy Problem - from GRE

**Physics Forums | Science Articles, Homework Help, Discussion**