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69dodge
18th August 2003, 07:16 PM
I have a dictionary that defines "center of mass" as:that point of a body (or system of bodies) at which its entire mass could be concentrated without changing its linear inertia in any directionWhat does that mean?

I know what center of mass is. What I'm curious about is whether the above definition, understood properly, gives some extra insight into the concept, or whether it is nonsense.

(P.S. Hey, how about that? My 127th post. You know, 127 = 2<sup>7</sup> - 1.)

Ziggurat
18th August 2003, 10:03 PM
I think that's a pretty poor definition in the sense that it's pretty confusing. But I think the point is, if you take an object at rest and collapse it down into a point, you need to impart some momentum to it if you want that point to be anywhere other than the original center of mass - it's got to move sideways to collapse to anywhere other than its center of mass.

Crossbow
19th August 2003, 05:39 AM
You have to be a bit careful when using standard dictionaries to define technical terms. If you want a better definition, then use a physics dictionary.