Page 1 of 3
Jeez, I hope this doesn't last too long...
Posted: Fri Aug 24, 2012 4:23 pm
by AlanOfTheBerg
Re: Jeez, I hope this doesn't last too long...
Posted: Sat Aug 25, 2012 7:07 am
by AlanOfTheBerg
jasonh300 wrote:So would 100% be 45 deg. or 90 deg.?
I imagine it would be 45deg where rise=run. Or run=fall.
Re: Jeez, I hope this doesn't last too long...
Posted: Fri Aug 24, 2012 10:54 pm
by bgodette
jasonh300 wrote:fvwazing wrote:14% means the road drops 14m if you drive 100m. That is pretty steep.
What is that in feet?
j/k
Yes, that's pretty steep. I did some research and the steepest grade on the U.S. Interstate system is 8%, and I have driven it (I-24/US-41/64 Westbound over Monteagle Mountain, TN).
For comparison, and I'm sure you drove it, the natural grade of Lombard St is 27% but the effective grade is 14% to 16%.
Re: Jeez, I hope this doesn't last too long...
Posted: Fri Aug 24, 2012 11:58 pm
by floppyrod84
We have 33% locally, and higher elsewhere.
Sent from my GT-I9100P using Tapatalk 2
Jeez, I hope this doesn't last too long...
Posted: Fri Aug 24, 2012 10:21 pm
by fvwazing
14% means the road drops 14m if you drive 100m. That is pretty steep.
Jeez, I hope this doesn't last too long...
Posted: Sat Aug 25, 2012 10:02 am
by fvwazing
1m down for 1m of road? 90 degrees, of course.
Edit:
Oops, my bad. Definition uses horizontal movement, not length of road.
Jeez, I hope this doesn't last too long...
Posted: Sat Aug 25, 2012 9:24 pm
by fvwazing
That is how I calculated/interpreted those roadsigns all the years! But harling was so assured that I looked it up -
http://en.wikipedia.org/wiki/Grade_%28slope%29 - and well, the difference is not sooo big if the percentage is small.
Re: Jeez, I hope this doesn't last too long...
Posted: Sat Aug 25, 2012 5:01 am
by harling
14% grade: arctan(0.14) = 8 deg.
27% grade: arctan(0.27) = 15 deg.
33% grade: arctan(0.33) = 18 deg.
Re: Jeez, I hope this doesn't last too long...
Posted: Sat Aug 25, 2012 7:54 am
by harling
AlanOfTheBerg wrote:jasonh300 wrote:So would 100% be 45 deg. or 90 deg.?
I imagine it would be 45deg where rise=run. Or run=fall.
100% grade (1m down for 1m forward): arctan(1.00) = 45 deg.
The "grade" of a vertical cliff is infinite.
Re: Jeez, I hope this doesn't last too long...
Posted: Sun Aug 26, 2012 1:44 am
by harling
I try not to apply my Math degree to
practical problems more than once a year. That was it.