A ball is thrown straight upwards from the top of a cliff with an initial velocity of 25ms^-1. On the way down it misses the cliff edge and falls on the ground 40m below. In addition to gravity, a drag force opposes the motion of the ball. The drag force is proportional to speed of the ball and the motion of which is described by: (d^2z/dt^2) = -g a(dz/dt) Note: take the drag coefficient, a, to be 1.1 Use Eulers method to solve the balls motion to determine how long it takes the ball to reach the ground and what its velocity is on impact (Answer is approx. 9ms^-1) (Bonus marks for using Runge-Kutta method)."

I used the Runge-Kutta method on a question before hand but Ive no idea where to start this question, any help would be appreciated. This is octave/Matlab