Activity for re89j
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Comment | Post #287178 |
Where did K come from?
And is there a name for the property of cylinders that they are proportional to the square of their diameter. I would expect that of perfect cubes perhaps but it is hard for me to understand how cylinders behave that way.
(Not saying you're wrong, at all. I admit this c... (more) |
— | about 2 years ago |
| Edit | Post #287175 |
Post edited: |
— | about 2 years ago |
| Edit | Post #287175 |
Post edited: Added Graph |
— | about 2 years ago |
| Comment | Post #287175 |
https://search.brave.com/search?q=area+of+a+circle
Look at that. the helpful snippet on the right of that search result page is incorrect. 2 pi r sounds like circumference to me not area. Pr^2 is area I think...
Yup, that was it. The spreadsheet finally looks plausible. (more) |
— | about 2 years ago |
| Comment | Post #287175 |
I made a sheet to run this formula and it's telling me that an 8 inch spool with 4 inch core and 6" material diameter is 50% full. That can not be. it must be less than 50% right? Since the outer two inches are larger rings than the inner two.....
https://docs.google.com/spreadsheets/d/14c3QMKsYy... (more) |
— | about 2 years ago |
| Edit | Post #287175 | Initial revision | — | about 2 years ago |
| Answer | — |
A: How to calculate remaining volume of a wire spool After I wrote up the question, I think the answer just hit me. Calculate the area of three circles: (was going to say cylindars, but I don't think that axis matters) a) the minimum/empty diameter b) the maximum/full diameter c) the current media diameter Then: b-a = the starting area of med... (more) |
— | about 2 years ago |
| Edit | Post #287174 | Initial revision | — | about 2 years ago |
| Question | — |
How to calculate remaining volume of a wire spool There are a bunch of rolls of 3d filament at my library in various degrees of emptiness/fullness. When I pick one I need to know that it likely has enough remaining for my print job. How can I calculate the (approximate) volume remaining of a spooled wire, given the diameter of the core/center of... (more) |
— | about 2 years ago |
| Comment | Post #285755 |
"it is invalid to divide by a quantity that "might" be zero [because] it [can cause] you to lose solutions"
^^ +1 THIS ^^
I wonder if it's just zero, or if it's any unknown value....
Dividing by an indeterminate value [can | does always] collapse a dimension of the problem, and so presents f... (more) |
— | almost 3 years ago |
| Comment | Post #285755 |
Is it accurate to say it is "not allowed" to divide both sides by something that includes a variable unless I can prove some other way that the denominator I'm creating can not result in 0?
In other words, I could divide both sides by a finite number or pi or something, but probably not by the var... (more) |
— | almost 3 years ago |
| Comment | Post #285755 |
So if 4ab=12b, and you want to know what a is, is it a bad idea to divide both sides by b? Is this example fundamentally different from dividing both sides by (5-x)? If so, why? (more) |
— | almost 3 years ago |
| Edit | Post #285753 |
Post edited: Probably best not to mention brand names |
— | almost 3 years ago |
| Edit | Post #285753 | Initial revision | — | almost 3 years ago |
| Question | — |
Missing a solution: Are A and B always equal if A-B=0 I just came across this problem on an online learning app: 4x(5−x)−12(5−x)+100=100 I tried to solve it by subtracting 100 from each side then inferring if something minus something else equals zero then those two things must be equal. 4x(5−x)=12(5−x) Divide both sides by (5-x) and x must ... (more) |
— | almost 3 years ago |