24K Pipe & the Banana Slug
By dcb on Feb 28, 2005
Here is an interesting little puzzle. It isn't so much a puzzle as a highly counter-intuitive reality. If you run the math to check your assumptions, you might think you've been hit by the Intel Processor computation bug. :-)
To help you out, the average radius of the Earth is about 3,959 miles, and the classic formula is: "circumference = 2 \* pi \* radius", where "pi" is approximately 3.14156. Polar (3,949.8 mi) and Equatorial (3,963.2 mi) radii are close enough to assume a perfect (smooth) sphere for this problem.
Your company has just completed a massive global engineering project. You've built a particle accelerator, a superconducting supercollider that circumnavigates the globe! A perfectly circular hollow pipe thru which protons and anti-protons are accelerated and smash into each other.
But just before you flip the switch to energize the superconducting magnets, the UN caves to the protest of environmentalists. Seems your pipe is hindering the migration of the revered Banana Slug in the forests adjacent to Santa Cruz (apparently there are a lot of laywers there with nothing better to do, except maybe sue IBM). You are commanded to raise the level of the pipe by 3 feet. Since the shape must remain a perfect circle, you must raise the pipe by this much around the entire length of the 24,850 mile pipe, not just there in Santa Cruz.
Try to guess the length of the segment of pipe you will need to add to raise the level of the supercollider by 3 feet around the entire circumference of the globe (multiple choice). After you've made a guess, go ahead and run the math.
- More than 5,000 feet
- 1,000-2,000 feet
- 100-200 feet
- Less than 20 feet
Extra credit: What if you wanted to "raise" by 3 feet a circular pipe with a radius equal to the distance between the Sun and Neptune (average radius = 2,798,842,261 miles)?
In case you give up, here is the solution: