By copying and pasting your spreadsheet from exercise 15, find and plot the values of L needed (in ft) vs. W, weight of jumper (in lbf) for successful bungee jumps (coming to a stop 5.0 ft above the ground) for K = 6.25 lbf/ft and from a cliff of height 150. ft above the ground. The graph should cover weights from 100. lbf to 300. lbf in increments of 25 lbf.  The function Goal seek under Tools is one way to solve this exercise.

At full stretch, the elastic rope of original length L stretches to L + x. For a person whose weight is W lbf and a cord with a stiffness K lbf/ft, the extension x is given by this formula:

 

and that can be written in spreadsheet script as x = W/K + sqrt(W^2/K^2 + 2 * W * L/K).

w2 2W x L W X=+ K*VK K