I got a homework problem the other day, and it was a conservation of angular momentum problem. Basically a bullet hits a rod, and a rod starts to spin. I needed to find how fast the rod was rotating. I didn't get the answer right, but I was looking up the answers, and it says that to convert it to the angular momentum, I had to divide my linear momentum by l/4(because the bullet strikes the rod l/4 over the center of mass.) So it looked like this: P = Linear Momentum = M(b)*V(b) + M(r)*V(r) AM =Angular Momentum = (I(b)+I(r))*ω P*L/4 = AM and then solve for ω Why does dividing by L/4 get me to Angular momentum? Or was initial momentum suppose to be covering linear momentum and angular momentum? So Initial Momentum should have been (initial Linear momentum + initial Angular momentum ) and Final Momentum should have been (final linear momentum + final angular momentum)?