This next statement is a big deal. It should be up on a board, surrounded by flashing red and yellow lights, and hung on the wall of every Science classroom. Although we never see it in our daily lives, it's fundamental to the workings of the universe, and it's also Newton's first law of motion:
<em>Without friction, it doesn't take <u>ANY</u> force to keep a moving object moving. </em><em>Force is only required to <u>change</u> the object's speed, or to <u>change</u> the direction </em><em>in which it's moving.</em>
The answer to the question is: On a level road, and neglecting any friction, the engine doesn't have to supply ANY force to keep the car going at the same speed.
The correct answer to the question above is that the magician is seeking the wavelength of the standing wave. The part of a standing sound wave, which is its wavelength, the magician is seeking when playing a musical note of a specific pitch.
