Finding volume with polar coordinate.

AI Thread Summary
The discussion revolves around estimating the volume of an irregular shape defined by a set of polar coordinates (r, theta, z) without any provided equations. The user contemplates using the area of a hexagonal projection multiplied by the average height as a potential method for volume estimation. They also consider whether to assume flat vertical sides between points or a curved surface. As additional points are introduced, the shape's complexity increases, resembling a sand clock. The user seeks clarification on visualizing these points to aid in their calculations and understanding of the shape.
isdouble
Messages
3
Reaction score
0
The question I have is a bit strange.
I do not have ANY formulas or equations given.
I was only given bunch of points with r, theta, and z. Z being the depth. R being radius and Theta being the angle.
I was wondering if there is a way to find a rough estimate volume of the following.
R Theta Z
0.5 0 0
0.4 60 0.1
0.3 120 0
0.4 180 0.2
0.5 240 0
0.4 300 0
0.5 0 3
0.4 60 3.1
0.3 120 3.1
0.4 180 3
0.5 240 3.2
0.4 300 2.9

Of course I tried using triple integral method but was immediately out the window since there is no equations to input. Any advice would be great. Thank you.
Oh BTW, this is a irregular shape so I cannot link it to any common shapes either..
 
Mathematics news on Phys.org
It looks like you have 6 points around the bottom and top. If you look straight down at these points you see an irregular hexagon shape. Are the vertical sides assumed to be flat between the given points like a hexagonal cylinder or are the sides curved and just pass through the six points of the hexagon shape? I'm thinking you could take the area of the hexagon projection times the average height maybe? What else do you know about the shape?
 
I got nothing. My prof just gave me these points and told me to find an estimated volume by using Excel VBA but I can't even use the VBA if I can't even solve the problem on paper. She told me there is no right or wrong answer so am I suppose to just guess what it's suppose to be? I was thinking about the same as you but that would be my last choice. Thanks for your input.
 
Here's a picture. The scale on the vertical axis is compressed. One could certainly imagine a cylinder like surface.

points.jpg
 
That's one part. I forgot to mention the second part. BTW thanks for the drawing. It's really helping. So for part 1, I'm going to assume that its a cylinder and use the volume formula to find it. For part B, there are more points added to the original.
R Theta Z
0.55 0 0.4
0.45 60 0.6
0.35 120 1
0.45 180 0.8
0.55 240 1
0.45 300 1.5
0.45 0 1.9
0.35 60 2.1
0.25 120 2.5
0.35 180 2
0.45 240 2
0.35 300 2
Now it changed the form from cylinder into a irregular shape.
I can kind of visualize it like a sand clock shape. (I think?)
I'm sorry but can you draw these points on top of the ones you drew previously?
That would help me visualize better.
Thank you.
 
isdouble said:
Now it changed the form from cylinder into a irregular shape.
I can kind of visualize it like a sand clock shape. (I think?)
I'm sorry but can you draw these points on top of the ones you drew previously?
That would help me visualize better.
Thank you.

This is probably pushing the boundary of how much I should do for you:

points2.jpg


Note that the lines aren't plotted in the order the points are given. You will have to sort that out.
 
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
Thread 'Imaginary Pythagorus'
I posted this in the Lame Math thread, but it's got me thinking. Is there any validity to this? Or is it really just a mathematical trick? Naively, I see that i2 + plus 12 does equal zero2. But does this have a meaning? I know one can treat the imaginary number line as just another axis like the reals, but does that mean this does represent a triangle in the complex plane with a hypotenuse of length zero? Ibix offered a rendering of the diagram using what I assume is matrix* notation...
Back
Top