and I thought you were a theodologian. On Sunday, January 5, 2014 4:00:48 AM UTC-6, Deacon Patrick wrote: > > Och! Good catch, Eli. Daft beggar I am -- my mistake once again making it > clear why I'm a theologian and not a mathematician. Grin. Thank you. I sen > demonstrate this by writing sin instead of sine. Dumb me. Dummie! Grin. > > With abandon, > Patrick > > On Saturday, January 4, 2014 6:14:42 PM UTC-7, Eli wrote: >> >> Wow, of all topics to get me to de-lurk, it's this one! >> >> I've always naively assumed that % grade was just a fraction of 90 >> degrees -- eg, a 45 degree slope would be a 50% grade. >> >> If it is based on the sine of the angle (the ratio of vertical rise to >> distance along the road) as Patrick says, then a 45 degree slope would be >> about at 71% grade, and a 30 degree slope would be a 50% grade. >> >> But according to this Wikipedia page >> http://en.wikipedia.org/wiki/Grade_(slope)<http://en.m.wikipedia.org/wiki/Grade_(slope)> >> it's >> actually normally based on tangent of the angle (ie, ratio of vertical rise >> to flat horizontal distance). In this system, a 45% slope is actually a >> 100% grade and a sheer cliff is infinite grade. >> >> Weird. >> >> For small angles, like you find on actual roads, the tangent- and sine- >> based approaches are almost the same (because flat horizontal distance and >> distance along the road are almost the same). But they're still both >> pretty significantly different from my naive assumption of what grade meant. >> >> A 10-percent grade, for example, means a roughly 5.7-degree angle using >> either sin- or tan-based systems, and not a 9% angle (10% of 90) like I >> would have thought. >> >> -Eli Daniel >> Snowed in in Somerville, MA and not riding my Sam today >> >> >> On Jan 4, 2014, at 1:25 PM, Deacon Patrick <[email protected]> wrote: >> >> I'll let someone smarter than me delve into the details, but if you take >> the degree of a slope and get it's sin you have the percent of the grade. >> Since I'm (and most of us) more familiar with the % rather than the degree, >> I translate it. >> >> Yes, Theodolite is the app I used for the photo. It's very handy, and I >> feel a bit like Luke Skywalker scanning the horizon in Star Wars whenever I >> use it. >> >> With abandon, >> Patrick >> >> On Saturday, January 4, 2014 11:12:48 AM UTC-7, Patrick Moore wrote: >>> >>> Looks like fun (except for the cold). >>> >>> What is the difference between slope and grade? >>> >>> >>> On Sat, Jan 4, 2014 at 10:36 AM, Deacon Patrick <[email protected]>wrote: >>> >>>> Slopes in pictures so rarely show how steep it actually is. Here is a >>>> study, using Theodolite to show the actual degree of the slope and a photo >>>> without it. >>>> >>>> Theodolite (reveals it’s a 7˚ slope, or 12% grade): >>>> http://www.flickr.com/photos/32311885@N07/11755929135/ >>>> >>>> Plain photo (looks like 4-6% grade): >>>> http://www.flickr.com/photos/32311885@N07/11756178903/in/photostream/ >>>> >>>> Oh, and the ride was wondrous! I did 7 miles in heavy snowfall and 15˚F >>>> and had a blast! >>>> >>>> With abandon, >>>> Patrick >>>> >>>> *www.MindYourHeadCoop.org <http://www.MindYourHeadCoop.org>* >>>> *www.OurHolyConception.org <http://www.OurHolyConception.org>* >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "RBW Owners Bunch" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> To post to this group, send email to [email protected]. >>>> Visit this group at http://groups.google.com/group/rbw-owners-bunch. >>>> For more options, visit https://groups.google.com/groups/opt_out. >>>> >>> >>> >>> >>> -- >>> Burque (NM) >>> >>> Resumes that get interviews: >>> http://www.resumespecialties.com/ >>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "RBW Owners Bunch" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/rbw-owners-bunch. >> For more options, visit https://groups.google.com/groups/opt_out. >> >>
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