Thanks! Before I was attempting to use the parallel axis theorem with the parallel axis at the elbow joint at the other end of rod ##m_2##. Why do we choose this way? My gut instinct without calculating is that it should yield the same result either way.
When I work this out I get ##I## =...
Could you expand a bit please? I would like to represent it in this way but I thought it might be simpler to do the trig first and understand that.
I've thought about how I'd go about it but I'm quite confused. I guess you might choose the axes as the axis through the center of the cylinder...
I didn't include both arms in the diagram, but I assume the other arm would also be at some angle to the torso, not necessarily the same angle as the arm pictured.
I'm trying to find the moment of inertia of a human body with (say) the upper arm at angle alpha to the torso and the lower arm at another angle beta, where beta is the angle between the lower and upper arms.
I model the torso as a cylinder of radius R, mass M and the parts of the arm as...