The Probert Encyclopaedia of Science & Technology

BALLISTIC PENDULUM

A ballistic pendulum was an apparatus formerly employed for ascertaining the velocity of military projectiles, and consequently the force of fired gunpowder. A piece of ordnance was fired against bags of sand supported in a strong case or frame suspended so as to swing like a pendulum. The arc through which it vibrated was shown by an index, and the amount of vibration formed a measure of the force or velocity of the ball.
Research Ballistic Pendulum