Mini Ballistic Pendulum Accessory The Ballistic Pendulum is an accessory to the Mini Launcher. It attaches to a Rotary Motion Sensor which measures the speed of the catcher assembly immediately after the collision, as well as the maximum height to which the pendulum swings. The Rotary Motion Sensor can also be used to measure the rotational inertia of the pendulum, for detailed study of the collision using conservation of angular momentum. The initial launch velocity of the ball can be calculated using projectile motion, or measured directly using photogates (not included). replacement foam inserts are available as a 5-pack (ME-6835) Includes: -Pendulum Arm with Catcher -Counter Weight -Ballast Mass