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Topic Date User

impulse force on cams 13-Sep-2005 At 11:01:39 PM richjs

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On 12/09/2005 ti wrote:
>Um, why did you need to presume that the cam was 15m off the ground? Is
>this so that you can factor in rope stretch? If so, would it be logical
>to say that the climber falls 11m (10m + 1m due to 10% rope stretch)? And
>from this calculate the time that the force is exerted on the cam?

Because when you are 5m above your last piece and it's 15m above your belayer, you have 20m of rope out. This means you'll fall 10m before stretch, and it'll be a ~Factor 0.5 fall. If the cam was right at your belayer, in which case it's a Factor 2 fall.. ouch (assuming it's a hanging belay so you don't deck out before the rope catches you!) Yet another reason why you should get something good in just off the ground.

Worry less about figuring out the actual force, and more about the fall factor - it's easier to calculate, and as meaningful.