Let's say I have a 50mm length of tube with a 28mm outer diameter. The wall thickness starts at .8mm and tapers to .6mm. What would be the total volume of that piece of tubing?
I can calculate the area of a cross section of that tube by adding the area of a right triangle and rectangle that make up the shape of the cross section: A = (.5 * 50 * (.8 - .6)) + (.6 * 50)
I don't know how to take that area calculation to find the total volume of the tube.
Thanks!
hint...from what you have described, the empty space inside the tube is a frustum. The volume of a frustum is $$V=\frac{\pi h}{3}(R^2+Rr+r^2)$$ where $h$ is the vertical height and $R$ and $r$ are the radii of the opposite end faces.
You have all the information to work this out, and you just need to subtract this from the volume of a solid cylinder.