(10%) Problem 12: The ballistic pendulum was invented in 1742 by English mathematician Benjamin Robins. It consists of an initially stationary pendulum that moves after being struck by a bullet, and it is used to measure the original velocity of the bullet. The known variables are the bullet's mass m, the Pendulum's mass M, and the height to which the block and bullet swing, determined by the length of the pendulum L and final angle θ.