\(\therefore 5, -\left( \alpha + \frac{1}{2} \alpha^{2} \right) :\) .....(i)

and velocity after first t sec

\(\mathbf{v} = \mathbf{u} + \alpha t\)

Now, \(S = -vt - \frac{1}{2} at^2\)

\(-\left\{s + \alpha \right\}t + \frac{1}{2} \alpha^{i}\) ..... (ii)

Equation (ii) – (i) \(\Rightarrow S_2 - S_1 = \frac{1}{2}at^2\)

\(a = \frac{s_2 - s}{t^2} = \frac{65 - 40}{(5)^2} = 1 \, m/s^2\)

From equation (i), we get,

\(S_1 = -i \alpha + \frac{1}{2} \alpha^2\) \(\Rightarrow 40 - 5x + \frac{1}{2} \times 1 \times 25\)

\(\rightarrow S_v = 27.5\) \(\therefore u = 5.5 \, m/s\)