Glob on the Table
On a frictionless table, a glob of clay of mass 0.56 kg strikes a bar of mass 0.74 kg perpendicularly at a point 0.39 m from the center of the bar and sticks to it.

If the bar is 1.06 m long and the clay is moving at 7.4 m/s before striking the bar, what is the final speed of the center of mass?
(in m/s)


At what angular speed does the bar/clay system rotate about its center of mass after the impact?
(in rad/s)

What are your specific questions here?

You have to use two conservation laws to find the answer. Energy conservation is not one of those two (this because the collision is inelastic -- a sure sign that some untrackable amount of the energy was turned into heat). Remember also that the angular momentum of a system could be represented as a sum of two angular momenta: Lc -- angular momentum of the center of mass and Li -- angular momentum of the bodies in that system relative to their center of mass.

You are free to select the point relative to which calculate angular momenta before and after collision. Because it is conserved irrespective of that. Why is it conserved? Well, because there are no extrnal forces here -- just internal. You would have to know what rod's moment of inertia is. Remember "frictionless"?

You will have to use Huygens-Steiner's (or something like that) theorem.

Pretty straightforward.