5.6-5.7 Centroids by integration & Pappus-Guldinus

Example:  Find the centroid of a triangle:

https://www.youtube.com/watch?v=Wg79PFCV2m8

I want this to be a statics class, not a math class, so you can use:

http://integrals.wolfram.com/index.jsp

Example:

Volume of Sphere from rotating semicircle around axis.

Use: http://en.wikipedia.org/wiki/List_of_centroids

(Circumference of a circle = 2*Pi*r)

Surface area of sphere:

5.8b:








Examples:

HW:

y=x=9a/20

x=(2/5)L, y=(12/25)h

V=31.91