March 31–April 6, 2009

Problem

(Suggested by Gary Raymond.) The Earth (assume a perfect sphere with radius R=3959 miles) is wrapped with a string around the equator. An additional 24π inches of string are added to the string. The string is then lifted at a single point until it is taut. Ignore the effects of gravity. The string is unstretchable.

  1. To what height is the string lifted above the earth at the topmost point (in feet)?
  2. What is the length of the string not in contact with the earth (in miles)?
  3. What is the area between the earth and the string (in square miles)?

Solution

here

List of solvers

Dustin Moody, Koopa Koo, Justin Shih (graduate); Gary Raymond (staff); Mark Morse, Lloyd Sakazaki, Greg Rudzinski, Mukund Tirumalai (outside).

Greg Rudzinski wins the prize!