Question:What can make your car such a big air drag, costing you gas mileage and money?
Answer: Start with speed squared (speed x speed), a bleeding gas hole as the pedal hits the metal, says Barry Parker in "The Isaac Newton School of Driving." Vehicle frontal area is another factor, obviously best when kept small, and frontal areas have certainly shrunk since the 1950s — unless you're SUVing or VANing or TRUCKing it.
How low can drag get? Ideal aerodynamic shape for cars is the teardrop, or fish—drag coefficient of about .03 to .04 —best if the streamlines follow the car's contour from front to back without breaking away, though this rarely happens. Instead, turbulence! Typically, the onrushing air splits at the front bumper, some going over the vehicle and some under. The air over splits just before the windshield, then rejoins and rushes over the roof, possibly splitting again at the roof's end. Or it may leave the car smoothly. The wake behind can also be a drag, worse when the car's end is cut off, called "bobtailing."
Underside drag is another problem, says Parker, as are radio aerials, mirrors, wipers, door handles, wheels and internal drag from air going through the car. And this doesn't even factor in the car's "skin friction" and "rolling friction" — but perhaps you're out of gas by now.
Question:You know of woodwinds, strings, brass and percussions from the Western symphony orchestra. What are aerophones, chordophones, idiophones, membranophones and electrophones?
Answer: They are the five Hornbostel-Sachs classes of musical instruments. This newer division is based on the physical characteristics of the sound source, making the categorizations more scientific, says David Crystal in "The Cambridge Encyclopedia of the English Language."
Aerophones have their sound generated by vibrating columns of air within, such as brass, reeds, woodwinds; chordophones include stringed and some keyboard instruments; idiophones generate sound with the instrument body itself, such as bells, the triangle; membranophones are drums, tambourines, etc; the newcomer electrophones add synthesizers, electric guitars and the like.
Most enthnomusicologists now prefer this system since it is broad enough to encompass "instruments" from anywhere in the world — panpipes, music boxes, maracas, carillons, conch shells, guiros, jaw harps, even bull-roarers, washboards and toy spinning tops.
Send STRANGE questions to brothers Bill and Rich at strangetrue@compuserve.com