Hi.
I intend to plot a function with a term 'F' which is dependant on the value of 'y':
m := 1200
k := 300000
b := 25
g := 9.81
F := If[y[t] < -0.4, -m g +
Abs[b (-y'[t]) Sqrt[y[t] + 0.4] + k y[t]], -m g]
y''[t_] := F/m
system = DSolve[{y''[t_] := F/m, y[0] == 0, y'[0] == 0}, y, t]
Plot[y[t] /. system, {t, 0, 5}]
The scenario is a falling object which can be modelled as a damper and spring; once it hits the floor then a bouncing force will arise, defined when y=-0.4. I am not sure how to go about this. Thanks for any help!