|
| Crowbar is correct. This is not a conservation of energy problem, but a dynamics problem. And I believe the governing equation would look something like:
mx” = Fp - kx
where,
m = mass pulling unit
Fp = maximum force of pulling unit
x = displacement from the point where all the rope’s slack is “taken-up”
k = rope’s “spring coefficient”
This of course is a second order differential equation. And quite honestly it has been too long for me to remember how to solve it off the top of my head.
But I will save myself the time and effort by saying that I would be left with the following assumption if I took the time to find the solution to the problem.
Buy a rope as big as your pocketbook allows. Eventually, you will end up with two smaller ropes that when combined, would equal the same length as the original rope.
That happened to our 80,000 lb rope, which I considered to be in excellent condition. We had to pull a crane that was stuck just a little ways forward with our Steiger ST310. I tried pulling it from a standstill and spun-out. So I backed up and pulled forward offsetting my spinout marks at a high idle in 1st gear and then “poof,” the rope exploded right in the middle. I would bet money that it did not have over 40,000 lbs of force on it when it failed. Also, it had previously withstood much greater stresses without any indication of failure. Anyway, there was no arguing that it did indeed fail, so it has been replaced with a bigger rope as of now. I guess time will tell if it will stand up to the abuse.
Mav
Edited by Mav 6/5/2013 15:49
| |
|
How much energy stored in a moving vehicle?
