For a 150 pound person who plans to jump off a ledge attached to a 42 ft. length of cord, the stiffness of the

cord (k, measured in pounds per foot) is related to the amount of stretch (s, measured in feet) by the function,

k(s) = 300(s+42)/s2

1.

If safety requirements will not permit the jumper to get any closer than 3 feet to the ground,

what is the minimum height required for the ledge? (Assume all previous findings still hold.)