\(s = \frac{1}{1-t^2}\)
\( \frac{ds}{dt} = \frac{0 -1 (1-t^2)^2}{(1-t^2)}\)
\(\frac{ds}{dt} = v = \frac{-(1-t^2)^2}{1-t^2}\)
At \(t = 2 ~sec\)
\(v = \frac{-(1-4)^2}{1-4}\)
\(v = \frac{9}{4} ~fps\)