Brainteaser Options

[james]

Here's a question for you:

"A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction). Can the plane take off?"

A couple of links discussing it (and some funny rationalizations for peoples incorrect assumptions):
www.kottke.org/06/02/plane-conveyor-belt
www.straightdope.com/columns/060203.html

[camsmith]

Alternatively, think about a matchbox car (I'm not talking about a wind-up car, simply a freewheeling model) on a similar (but smaller) conveyor.

The force applied to the matchbox car comes from your hand, not from the wheels on the conveyor. You would still be able to push the matchbox car off the end of the conveyor, regardless of how fast someone wants to make the conveyor move.