Pi * d to the fourth power all over 32 ((pi*d^4)/32)

[Endangered Specie]

Any guesses on that one?

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1. you figured out how to square the circle?

[Endangered Specie]

3. Be more specific.

[LynzM]

2. Erm, dammit, I knew this!

At least, I think I knew this.... dammit, nope, I'm imagining things again.

[X_republican]

4. You got me on that

one.

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5. volume of a 4-dimensional sphere?

pi*(d^4)/32
=
pi^((2*r)^4)/32
=
(16*pi*r^4)/32
=
(pi*r^2^2)/2

pi*r^2 of course is the area of a circle.
you've squared this so you've added 2 dimensions,
so it's a 4-dimensional sphere.

i'm guessing volume.

[Endangered Specie]

7. The volume of a 4-d sphere would be infinity I believe...

(I got this from a Civil Engineering class, so I doubt it has to do with 4-d objects)

But assume you really meant a 4-d "volume".

Anyways

(pi*r^2)^2 = (pi*d^2/4)^2 = (pi^2*d^4)/64

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10. might have to punt, i know zero about civil engineering.

does that mean this has something to do with building bridges?

[Endangered Specie]

11. It has to do with Torsion in a beam. (answer inside)

"Polar Moment of Inertia" (I-sub-p) used in this equation:
Shear stress = Torque*radius / I-sub-p IF your are trying to find the shear stress in a (cylindrical) beam of given radius and some applied torque... Important to know if that shear stress is more than the beam can take without breaking.

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12. does this mean how high can i rev my engine before the axle snaps?

[Endangered Specie]

13. Hopefully...

the person who designed it put an axle that could withstand the torques the engine was capable or producing, but, in a way that situation does apply.

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8. after a little googling,

the sources i'm finding from math geeks, not necessarily authoritative, but it looks like the volume of a 4-dimensional sphere is

(pi^2*r^4)/2

which is equal to what you've got except you have pi instead of pi^2.

[Endangered Specie]

9. Only trouble is I didnt get this from a math class

Although the coincidence is interesting.

[onebigbadwulf]

14. Spheres are 3 dimensional

its the formula for a sphere.

4-d includes time which this formula does not.

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15. uh, wrong

a fourth dimension is a mathematical concept, having many theoretical and practical manifestations.

time as the fourth dimension, (with length, width, and depth being the first three) is merely one such manifestation (and application of a mathematical concept to physics.)

it's not true that a fourth dimension is not represented in the formulas we're discussing, nor is it the case that there can't be a meaning that applies one of those dimensions to time.

[jfalchion]

6. what's nu?

C/lambda