I don't think ANYONE has EVER considered the Wedgie Factor, either. In the transition from unweighted harness to weighted one, the harness becomes quite intimately well, intimate with the wearer. You're especially familiar with that if you've ever climbed sans underwear. What about that extra 3-6" of give as climber compresses into the harness on a hard fall? That's 6-12" of extra squish when you count both climber and belayer. Even more if we're talking about cows, as long as they're non-rigid cows.

Rob

Drunken texan (W?):

Extra ghetto climbing physics: If a factor 2 fall is like a 2000lb load on the climber, is a factor .3 fall a 2000/(2/.3) = 333 lb load on the climber? Kinda breaks down on real small fall factors though...

BTW - it _is_ constant. If you don't think so - you don't know what a spring constant is.

http://www.vishay.com/brands/measurements_group/guide/glossary/spr_con.htm

I'll withdraw the assertion that they don't.

b----... are those indusrial strength paper clips load reducing at high forces??

'Ma! I sah besty a rock clamberin!'

What do you think of my climbing cows photo?

(plus the 2004 BW catalog has a pic of sharma with the reddest eyes I've EVER seen, friggin rad)

From http://www.bealplanet.com/produits/anglais/produit1.html

For the beal 10.2 Flyer II rope:

Imapct force: 7.4 kN
Extension during first fall: 37 %
Static elongation: <= 10% (less than or equal)

So making an ass of u and me:

spring constant for static case:

F = 80 kg * 9.81 m/s^2 = 0.78 kN

k = F/x = 0.78kN/0.1 = 7.8 (kN/%)

for first fall:

k = 7.4kn/.37 = 20 (kn/%)


so the spring constant is 7.8 for the static and 20 for the first fall, so the spring constant does change??

Ghetto physics disclamers: k in kN/%??? a little weird but i think it'll work, also the first fall should be less than 7.4 kN, but that just makes the spring constant bigger, also the elongation for the static case is less than or equal to 10% but whatever, close a f---ing nuff. That and bluewaters figures are pretty similar (plus the 2004 BW catalog has a pic of sharma with the reddest eyes I've EVER seen, friggin rad)

Shank, good attempt, but no cigar:

Correct, but it should be lbs-m (pounds of mass)

No, the climber falls for 9.8m. If he was moving at 9.8 m/s then yes, it would take (9.8 m)/(9.8 m/s) = 1 s but the climber starts with a velocity of 0 m/s. So the climbers velocity after falling 9.8 m is:

V = sqrt(2*a*x) = sqrt (2*9.8m/s*9.8m )
V = 13.9 m/s

And the fall takes:

V = a*t
t = V/a = (13.9m/s) / (9.8m/s/s)
t = 1.4 s


And to doulbe check:

x = (1/2) *a*t^2 = (0.5)*(9.8m/s/s)*(1.4s)^2
x = 9.6 m (not 9.8 but i did some rounding so... )



Problem: I'm not sure where you got that 7% stretch, but I'm assuming its in relation to either a static loading of the rope or the strech during a UIAA test fall, either way, the amount the rope streches is going to vary on the the imact on the climber which will be related to the fall factor and friction between the rope and biner(s). So, nice idea, but using that 7% is a no go.

So i didn't really help figure out the load, but thought i could help clean up the physics. If i f*cked anything up somebody correct me, its been a good year and a lot of brain cells since i got outa school.

Mike

so the spring constant is 7.8 for the static and 20 for the first fall, so the spring constant does change??

Classic. I do have to point out, though, that your cows are not spherical.

Rob

Yeah, that's the kind of stuff I read. Given the static figures, a hard fall should stretch the rope a lot more than it actually does. Like 70-90%, which I think just doesn't happen ever. But whatever. I don't have conclusive data or sufficient credible information, so I'm not drawing a conclusion on that one yet.

Rob

Hmmm, sounds like jxl914 (WTF??) got aroused by the spherical cows and now feels embaressed.... It's alright man, cows need loving too. You can't fight who you are...