# Lagrange constraint mechanics problem

by DylanG
Tags: constraint, lagrange, mechanics
 P: 5 Just a simple question. I can see that for this to work I need: Trot = 1/5 ma2(thetaDOT + phiDOT)2 Just can't work out what phi has to do with rotational kinetic energy. I would have thought it would need to be simply the same thing but without the phiDOT term.
 HW Helper P: 2,156 $\theta$ is the angular position of an identified point on the smaller sphere, measured with respect to the line joining the centers of the two spheres, right? Note that not only does $\theta$ change with time, but so does the orientation of that joining line, so you need to take that into account as well. That's where the $$\dot\phi$$ comes from.

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