Chockstone Forum

      Sponsored By
      ROCK
   HARDWARE

Chockstone Photography

Australian Landscape Prints

Chockstone Forum - Gear Lust / Lost & Found

Rave About Your Rack Please do not post retail SPAM.

Topic Date User

impulse force on cams 12-Sep-2005 At 3:38:34 PM uwhp510

Message

If there is 20m of rope out then 10% stretch is 2m, not 1m. The whole thing is an idealisation anyway, so the fall of 10m is used to calculate how fast the climber is going when the rope starts to catch him/her. The deceleration won't begin until the force due to the rope catching the climber is equal to the climbers weight which would be sufficiently close to the point at which the rope came tight that it wouldn't make much difference to the outcome anyway, and would be much harder to calculate.

I would reccomend doing a numerical simulation using (Hookes) law for a spring (F=kx, where k is a constant and x is the displacement from equilibrium), and newtons second law (F=ma) and stepping though the situation with a small time step, if you want a more accurate number. You could use excel for this.