Thread: Geometry of a spiral?

Hello all, wonder if you can help me? I'm an engineering student but obviously haven't been studying that hard because I can't work out this problem:

I want to create a spiral, I know the total length if it were stretched out and I know the thickness...the best way I can describe it is as if you had a bit of rope that was 5mm thick and 4m long, then you coiled it up in a spiral on a table or something. The question is, is there a general formula to work out how many revolutions the coil would have and what the overall diameter would be?

Any help much appreciated!

Originally Posted by jonny2x4

Hello all, wonder if you can help me? I'm an engineering student but obviously haven't been studying that hard because I can't work out this problem:

I want to create a spiral, I know the total length if it were stretched out and I know the thickness...the best way I can describe it is as if you had a bit of rope that was 5mm thick and 4m long, then you coiled it up in a spiral on a table or something. The question is, is there a general formula to work out how many revolutions the coil would have and what the overall diameter would be?

Any help much appreciated!

Have a look here: Archimedean spiral - Wikipedia, the free encyclopedia