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Impact factor calculations and microwire placement 23-Nov-2009 At 7:23:42 AM mikl law

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Ittake a while to churn through that doesn't it.
The important point is that if a piece pulls it doesn't really absorb much energy or slow you down much:- Attaway did a nice paper where he showed that with equally spaced equally bad gear and the top piece fails, they will all fail. So you need to eiother equalise a bunch of bad gear, or climb on doubles (the load is spread over 2 pieces if they are within a meter or two so only half the load comes on each, and the impact force of a thin rope is less).
Or get your belayer to let slip the rope.
The Wexler equation covers all this, I don't have a web reference for it, but it was a neat piece of work which invented the "fall factor" long before we had nylon ropes.
Attaway also had a more accurate fit to rope forces
http://web.mit.edu/sp255/www/reference_vault/second_order_rope_fit.pdf