juliom_at_cisco.com wrote: > > > Therefore F = V sqrt(kM). > > > Cool formula! Awesome work! > > > Substituting weight for mass F = V sqrt( k w/g) where g = acceleration > > of gravity. > > F = 52.8 sqrt[ (1.6 * 300)/ (386.4) ] = 58.8 lb. > > Water tends to be horizontal, though. Or are you referring to the case where > both boats become airborne and during the trip down one of them > gets entagled in a tree? :-D > > The acceleration is the key factor here. And apparently you used > the acceleration of gravity to find your k's. > The relationship between mass and weight is the same F = Ma, in this case, a is that due to gravity and F is the weight, hence: w = Mg or M = w/g which is what I put into the equations. > But I digress. > > The maximum acceleration that the human body can > withstand for a very short period of time without suffering injury > is 20 g's. [...] Mine is a _static_ analysis without considering the dynamic loading. In the commentary I intend to write RSN, I'll explain the difference and the reason why I haven't done that. I have my dynamics book here, so I may break down to do it anyway. No time tonight though. > k < 4491.2 meter^2/second^3 > > There you have it, k for a spring to prevent injury on a towing paddler. k has to have the units of pounds per inch or newtons per meter. The error I made, for those that want to work it out for themselves is that I measured k for an 8 inch section and didn't normalize it out so that it could be applied to any length of bungie. But that introduces the length of the bungie into the equation where it wasn't before. That complicates things a bit. Tomorrow I get to take Amie out to dinner, so I may have to wait til Wednesday to finish it. Don't worry, I will. Mike *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Mon Oct 18 1999 - 18:22:36 PDT
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