Friday, July 11, 2008

More Bad Usage Of Physics Terminology

I mentioned earlier about the media's abuse (misuse?) of the phrase "rate of speed". They mean one thing, but the words/phrase they actually used means something else. Well, here's another one.

This gem comes to use from, of all places, the New York Times editorial column, no less! It was an article written about the oil rush in Iraq. You can read the content for yourself since it isn't relevant to the issue. But read the very last paragraph of the editorial.

The United States and the oil companies must encourage Iraqi officials to make the political compromises needed to establish in law the rules for managing Iraq’s abundant natural resources with as much transparency as possible. Otherwise, oil will just become one more centripetal force pulling the country apart.

"Centripetal force" doesn't normally pull things apart. If anything, it pulls things INWARDS, together. Centripetal force provided by gravity is what keeps satellites and planets in orbit rather than flying apart. It is a "central force", acting inwards towards a force center.

What they meant in this article is "centrifugal force", which is a "fictitious" force. It is the result of being in a non-inertial reference frame and experiencing a body's tendency to maintain its inertia. Thus, in a circular motion, if you sit on the body that is moving in that circular motion, you feel an outward "force" pulling you out.

So ironically, if they had used the common centriFUGAL force as the analogy in this article, I wouldn't have paid that much attention to it, because while it isn't really a real force, the analogy is, nevertheless, accurate. But using centriPETAL force in this context is definitely not if they intended to make that point of things being pulled "apart".

Zz. {Going off to nitpick some other issues}

1 comment:

Kent Leung said...

The problem is that in physics classes in school, whenever you mention "centrifugal" force, the teacher would say it does not exist. I think that this comes about, even in teachers, is that when textbooks call a force "fictitious", it is not the usual everyday meaning of the world. In terms of mechanics, it has a very special meaning.