Courses: P3, P13, P15
A heavy ball is launched at a pendulum, where is sticks. The pendulum swings upward and is prevented from falling back down by a ratcheting mechanism. While a simple approach to solving this problem works reasonably well, apparently "the accuracy of the Cenco Blackwood pendulum is improved by at least 4 percent if it is considered a conservation of angular momentum and conservation of energy in rotational motion problem." (AJP 44(2), 182)
