Creative Commons License Copyright © Michael Richmond. This work is licensed under a Creative Commons License.

Computing the center of mass

The center of mass is an important feature of single objects, and perhaps even more important for collections of objects.

Now, when an object is a compact sphere, the center of mass is easy to find: it's just the geometric center of the body. But what happens if we need to find the center of mass of a system consisting of several objects?


What about extended objects? Some of the nice rules you've learned so far in the class, such as


    " ... in projectile motion, the x-velocity remains 
      constant while the y-velocity changes linearly with
      time.  The trajectory of an object thus traces
      a parabolic curve ...."

don't seem to work if you pick any arbitrary part of an extended body. For example, if I toss a baseball bat up into the air, a movie might show this:

Speaking of real movies, look at this real motion of a sort of dumbbell-shaped object:

But how can we find the center of mass of an extended object?

Creative Commons License Copyright © Michael Richmond. This work is licensed under a Creative Commons License.