(1) \(a = -2\alpha v^3\)
\(t = \alpha x ^2 +\beta x\) (differentiating wrt time)
\(\frac {dt}{dx}= 2 \alpha x + B\)
\(\frac {1}{v} = 2\alpha x +\beta\)
(differentiating wrt time)
\(-\frac {1}{v^2}\frac {dv}{dt}= 2\alpha \frac {dx}{dt}\)
\(\frac {dv}{dt}=-2\alpha v^3\)