Talk:Atomic Structure

Centrifugal force is actually a fictitious force. It seems to exist, but this is illusory. see [1]. I am not very adept at stating the nature of the matter (something I only kind of got in physics 40 years ago), but I'll give it a try:

All particles in motion tend to continue in that motion (this is one of Newton's Laws of Motion). A particle in motion has a force equal to mv, where m = the mass of the particle and v = its velocity. This force is also termed "momentum." (see [2].)

Now, when a particle in motion is acted upon by another force, the path of the particle's motion changes.

For example, as the moon orbits the earth, the earth's gravity is continuously exerting a force on the moon, pulling the moon toward the earth. HOWEVER, the moon is so perfectly positioned in relation to the earth that its momentum (which is acting at a right angle to the earth's gravitational force) is sufficient to balance the pull of the earth's gravity.

If the earth's gravity could be canceled for a moment, the moon would go shooting off, NOT directly away from the earth, but at a tangent to the moon's orbit. This is easy to explain by drawing but hard by words alone.

The moon's momentum would have the moon go shooting off on a tangent, but for the earth's gravity. So, the moon is perpetually falling around the earth.

Physicists would use concepts of "angular momentum" and "angular acceleration" to explain this whole thing. I know "about" the matter, but I don't know it well enough to express it succinctly for the Wiki. If you know a high school physics teacher, perhaps he or she could could give us a suitable summary.