Volumes of Revolution Cross Sections

ChemE14
Thu, 29 Apr 2010 00:18:07 +0000

I think I confused area with base because I was trying to explain that you take the area you found in the first part to use as the base in the cross section part of the problem. Usually it is stated that the region from the first part is the base.



I’m pretty sure you get the idea, but just wanted to point out to those who don’t that this phrase isn’t completely right. In those equations, “base” represents the length of the line from the upper bound to lower bound, not the area of the whole region. What you’re doing when you’re integrating this area function is adding up an infinite amount of cross-sections. I think of it as adding up a lot of very thin “slices” (the cross-sections) to get the total volume of the solid.

If that confused anyone, sorry, I have trouble explaining it. My main point to get across was that “b” (the base) is not the area of the region but a distance from the top to bottom of that region.