Q. A ballistic pendulum consists of a chunk of clay suspended from a rope. While a bullet is fired into clay it sticks causing the clay to swing. This is an instance of a totally inelastic collision. If the velocity of pendulum after the collision can be measured, after that the Law of Conservation of Momentum can be used to calculate how fast bullet was travelling before the collision. A 0.04 kg bullet collides in elastically with a 0.5 kg ballistic pendulum. Before the collision the pendulum was at rest but immediately after collision the pendulum is moving with speed of 13.6 m/s. How fast was the bullet travelling before the collision?