Real-world Problem for Chapter 13 - Swinging Chandelier

Write a complete solution to the following problem using the GOAL problem-solving protocol.  Carefully consider any assumptions you make in solving the problem, along with an explanation of how the answer would vary under different conditions.  Clearly specify any estimations you make, and be sure your answer will agree with anyone else who correctly analyzes the same problem.

While sitting in church one Sunday, you notice a large chandelier swaying slowly as it hangs from a heavy chain attached to the apex of the cathedral.  You decide to repeat Galileo's famous observation by timing the period of this motion with your pulse.  You count 5 pulses of the beat of your heart in the time that it takes the chandelier to make one complete oscillation.  You estimate that the bottom of this chandelier is about 10 feet above the ground.  How tall is the cathedral?  Estimate the uncertainty of your result.