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rmfw
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Homework Statement
An homogeneous cube of mass M and side 2a spins around one diagonal of the faces with constant angular velocity w. Show that the size of the angular moment in relation to one of the fixed vertexes is [itex] \sqrt{\frac{43}{3}}Ma^2w [/itex]
What I visualize here is a cube with one of its vertexes on the origin and then it spits in a way that the vertex on the origin is always keeps there.
Homework Equations
[itex]\vec{L}=\vec{L}_{cm;O} + \vec{L}_{rel cm} = I \vec{w} + I_{cm} \vec{w}[/itex]where I are inertia tensors
The Attempt at a Solution
I was able to calculate the inertia tensors:
[itex] I =Ma^2 \begin{pmatrix} \frac{2}{3} & 0 & 0 \\ 0 & \frac{2}{3} & 0 \\0 & 0 & \frac{2}{3} \end{pmatrix} [/itex]
[itex] I_{cm} =Ma^2 \begin{pmatrix} 2 & -1 & -1 \\ -1 & 2 & -1 \\-1 & -1 & 2 \end{pmatrix} [/itex]
but now I'm stuck on what the vector w should represent, I think it has something to do with euler angles.