A wood block of 2.5 kg suspends from the bottom of a 1.1 kg, 1.3 m long rod. The block and rod make a pendulum which swings on a frictionless pivot at the top end of the rod. A 13 g bullet is fired into the block, where it sticks, causing the pendulum to swing out to a 32 circ angle.
Find out the speed of the bullet? You can take the wood block as a particle.