Take the 2-minute tour ×  I'm having some trouble with a simple
classical mechanics problem, where I need to calculate the
center of mass of a cone whose base radius is $a$ and height
$h$..!  I know the required equation. But, I think that I may be
making a mistake either with my integral bounds or that $r$ at
the last..! $$z_{cm} = \frac{1}{M}\int_0^h \int_0^{2\pi}
\int_0^{a(1-z/h)} r \cdot r \:dr d\phi dz$$  'Cause, once I work
this out, I obtain $a \over 2$ instead of $h \over 4$...!  Could
someone help me?  share|improve this question Hello there
Coolcrab and please keep an eye on our Homework policy before
asking about homework questions, 'cause they're discouraged
here..! Sorry :) –  Waffle's Crazy Peanut Sep 29 '12 at 10:16
They are not homework, and I did do the sum just making a
mistake somewhere. And asking for help with that.. –  Coolcrab
Sep 29 '12 at 10:55 What!? $a/2 := h/4$!? I don't think so...
Increasing $a$ has no effect on $h$, this assertation is plane
false. –  Killercam Sep 29 '12 at 11: