Bungee Jumper with Y axis upside down [closed]

So I was reading about ODEs in Chapra’s “Applied Numerical Methods with Matlab”. So he considers bungee jumper problem, mainly system of differential equations with respect to the distance and velocity and detecting the moment the jumper landed. I wonder what the formulas would be in case The Y axis was not upside down (if it was normally in the upward direction) ? Like what if we had y0 = [200 -20] instead of [-200 -20]? How would the other part of codes change? Here are corresponding codes for this question.enter image description here

freefall ODE system

detector function

detection code