The ballistic pendulum was developed to measure the launch velocity of a high-speed projectile.  A launcher fires a ball into a catching cup on the end of a pendulum rod.  The pendulum swings up to a maximum angle.  Recording this maximum angle and measuring the mass of the ball, the mass of the pendulum and the length of the pendulum, the launch velocity of the ball can be determined.

m_ball                  = 0.0661 kg

m_pendulum            = 0.1672 kg

r_pendulum             = 0.355 m