In forensic science, it is useful to measure the speed at which
firearms propel bullets. Before modern instruments, this was done
with a device called a “ballistic pendulum”, consisting of a block
of some soft material hanging from the end of a string. The
experimenter fires a bullet into the block, which lodges into it;
the block swings up at an angle. By measuring the angle, the
experimenter can determine the velocity of the bullet.
Suppose that you are a...