David_Campen wrote:yes, it is that simple.
So, then where does friction fit into the equation? There are variables. What if the rappeller descended without a rope? I doubt 400+ degree (F) temps would be generated then.
Moderator: Tim White
David_Campen wrote:yes, it is that simple.
As to the "bounce=lost energy" equation, it makes sense to me, tho like Scott I didn't do so well in HS Physics.
What if the rappeller descended without a rope?
cob wrote: As to the "bounce=lost energy" equation, it makes sense to me
Scott McCrea wrote:David_Campen wrote:yes, it is that simple.
So, then where does friction fit into the equation? There are variables. What if the rappeller descended without a rope? I doubt 400+ degree (F) temps would be generated then.
David_Campen wrote:The solution to that is to learn how to frog properly ; there is just not that much difference between the ropes.
cob wrote:...I heard their pleas for help. Neither knew how to down climb, ...tom
RescueMan wrote:With a 300 lb load, the BWII+ 11.6mm has about 2.3% elongation, Sterling HTP 12mm 1.4%, PMI Classic 11mm 1.2%, (all of these ropes are labelled 7/16").
RescueMan wrote:Actually, there's quite a bit of difference in the static elongation of the various ropes.
With a 300 lb load, the BWII+ 11.6mm has about 2.3% elongation, Sterling HTP 12mm 1.4%, PMI Classic 11mm 1.2%, (all of these ropes are labelled 7/16").
The static stretch of the BW is double that of the PMI. That makes a difference.
- Robert
David_Campen wrote:I suppose a good bit of energy could be going into friction of the rope fibers rubbing against each other as the rope flexes around the bars of the rack so that a significant amount of heat is deposited inside the rope and all along its length. Also that different ropes could exhibit different ratios of internal friction due to flexing vs friction from the rope rubbing against the rack bars.
Hmm, is this what you were suggesting in your earlier post?
But, wouldn't the friction between the sheath and the bars have a much greater influence on the temp readings?
David_Campen wrote:The type of rope, bars, rack, speed etc does not affect the value W times D that has to be converted to heat if the rappeller is to be traveling at near zero speed when they touch the deck.
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