- #1

Rhi

- 10

- 0

## Homework Statement

A straight wire has uniform density and total mass M. The wire is bent to form a closed loop, one section of which is a semi-circle of radius a, and the other section the diameter joining the two ends of the semicircle. The body is free to move about the midpoint O of its straight edge. It rotates at constant angular speed about an axis through O in the plane of the body and perpendicular to its straight edge.

Using T=J

_{ij}*ω

_{i}*ω

_{j}/2 or otherwise, show that T=(1/12)Ma^2ω^2((3π+4)/(π+2))

## Homework Equations

J

_{ij}=∫ρ(r

_{k}r

_{k}δ

_{ij}-r

_{i}r

_{j})dV

## The Attempt at a Solution

I've worked out that ρ=M/(a(π+2))

I'm struggling with how to do the integrals, as its such an odd shape off to the examples we've done (cubes, etc). I tried to do the semi-circle bit and the diameter bit separately, but then I don't get aything like the answer I'm supposed to. Any pointers would be appreciated! :)