It's the same as the bird in the cage question. I might expect such a question going for an engineering or a physicist's position. One question I was asked was:
Two bicycle wheels, one covered in grease and the other with sticky paint. If you let them both go down a hill which will reach the bottom first ? I got the position but turned it down for somewhere else. Don't try to guess the correct answer since it's never the answer that matters but how you get there. Sometimes there are no correct answers.