a bungee jumper of mass 80kg jumps from 20m, bungee cord has an original length=4m, end of cord in 2m from the bottom when jumper is momentarily at rest at the bottom. find k value.

why can't you use f=kx to solve, where f=mg and x=14?

1 answer

because the stretch stops when the kinetic energy has all been stored in the cord, which is 1/2 kx^2