Demo 05-11 Ballistic Pendulum

A ballistic pendulum can be used to measure the speed of a projectile. The projectile, in this case a ball that is shot by the device, is caught in the pendulum receptacle, conserving angular momentum. Because of the distribution of mass in this pendulum, angular momentum (rather than linear momentum) is conserved in the collision in which the ball is caught. After the collision, the energy in the system raises the center of mass of the combined ball and pendulum, converting rotational kinetic energy into gravitational potential energy. Measurement of the height to which the center of mass rises allows determination of the initial speed of the ball. Marks are shown on the screen indicating the position of the center of mass of the system just after the collision and when the pendulum rises to its highest point, as shown in Figure 1