A vertically oriented uniform rod of mass M and length l can rotate about its upper end. A horizontally flying bullet of mass m strikes the lower end of the rod and gets stuck in it; as a result, the rod swings through an angle Ī±. Assuming that m<(a) the velocity of the flying bullet;
(b) the momentum increment in the system "bullet-rod" during the impact; what causes the change of that momentum.
