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hardnox604008
Veteran Advisor

Any math whizzes?

My memory of geometry is failing me so I'll do it the lazy way- ask somebody.

 

If you pile 250 tons of potash on a floor, how much area will it take up?

 

Pounds per cu/bic foot= 70. Angle of repose is 30 degrees.

 

Whatday think?

11 Replies
kraft-t
Senior Advisor

Re: Any math whizzes?

According to my calulations an inverted cone at 30 degree angle of repose 8.25 feet high by 57 feet in diameter would contain a volume (drum roll) 7100 cubic feet which equals roughtly 500K lbs/ 70 lbs.

 

Lack confidence in old Kraft-t?  Do a google search for "volume of a cone" There are plenty of options or formulas available on the web.

hardnox604008
Veteran Advisor

Re: Any math whizzes?

Thanks Don,

 

I was approaching the thing from a wrongheaded point of view from the start- thinking in terms of a rectangular pile which was causing me some difficulty.

 

The hypotheetical pile would be somewhat rectangular in nature but the cone works just fine for the purpose of estimation.

 

Thanks, h

 

BTW, as to some questions about the state of the educational system- either my father or grandfather could put me to shame in terms of knowledge of math. I supppose they'd both had plenty of time sitting on a tractor to think through the mathematical proofs but both could easily explain how they arrived at the area of an irregular field, etc.

 

 

tomtoolbag
Veteran Advisor

Re: Any math whizzes?

  Good job Mr. Kraft. I started to work it out and got sidetracked by a problem, and my calculator with sin and cos is an oldy, and I had to stand by the window to get it to power up.

  Stupid me, I didn't think of using the web and a online calc. I should of had jr. come in here and do it while I wired up a switch on the truck, instead of the other way around. He's pretty good at it and it just shows me how much I've forgotten.

hardnox604008
Veteran Advisor

Re: Any math whizzes?

After thinking about how to do the calc on a long pile, what you have to do is take 2 half cones to make 1 (both ends, then measure the length of the peak to peak height and split that into two wedges.

tomtoolbag
Veteran Advisor

Re: Any math whizzes?

  Yeah, it would be like a roof measurement then with the angle/rise over run.

kraft-t
Senior Advisor

Re: Any math whizzes?

I was a math major in college and geometry was kind of my forte. Unfortunately I forgot most of what I knew. I just did a google search on the volume of a cone and lucked out.

GreaTOne_65
Senior Contributor

Re: Any math whizzes?

Good job, Don. I could have done it long hand, but I would have needed one of my seed books. Even though I have learned a lot on the computer, until you said you googled it, did the light bulb come on. Great job.

Canuck_2
Veteran Advisor

Re: Any math whizzes?

I always seemed to struggle with math at least 'mental arithematic' that they used to like to train us with in school.

One girl in our highschool class would have the answer about the time the teacher finished reading the question.

Like Great One I always had to dig out the book and then I could work through it.

Was I ever glad to get pocket sized calculators and then computers with spread sheets.

 

Further to the topic of math my son who gets math easy and works in IT was just telling me of someone older than him who was discussing how 'they used to do it' before computers and he mentioned slide rules. My son was aware of those old antiques because I have always had one on a shelf above my desk, just to remind me that I never really figured the dad-begumed thing out.

kraft-t
Senior Advisor

Re: Any math whizzes?

In 1982 I filled a new machine shed with corn. The farmer owned reserve. When the ASC came out to measure the amount of corn in the bin they were stimied as to how to calculate it. The building was 60 X 99 with a six foot high grain liner around the perimeter.   So the corn was 16 ft deep in the center and there was a 20 foot flat area on the topat the deepest point. I don't remember but I assume the angle of repose was about 40 degrees from the highest poin to the 6 ft high grainliner walls.

 

The measure guy tried for quite a while and finally asked me how much I thought was in it. I had previously calculated it by segmenting the pile in various shapes. Base rectangle of 60X99 X 6 foot deep. Then another rectangle with the Upper section which was  20 ft wide X 60 foot long X 10 ft high.

 

Thus I had the botton 6 ft measure and the `middle 10 ft above that measured. The rest was picking out triangular segments  which matched up with the angle of repose. Of course it wasn't an exact calculation but it was pretty close just by figuring  trianglular piles by the various lengths such as  20 ft wide X 60ft long X (10 ft high / 2 )  which was the average height.

 

So I kept breaking down the pile into different segments and calculating the volume of each segment.

 

So there s a method to figure your pile should it be 8 foot high by 50 ft wide by 100 ft long.

 

I hope that s at least as clear as mud.