[tex]v_f = v_i + at\ \to\ v_f = 15\ \frac{m}{s} + 0, 5\ \frac{m}{s^2}\cdot 40\ s = \bf 35\ \frac {m}{s}[/tex]
[tex]s = v_i\cdot t + \frac {1}{2}\cdot at^2\ \to\ v_i = 15\frac {m}{s}\cdot 40\ s + 0, 25\frac {m}{s^2}\cdot 1600\ s^2 = \bf 2000\ m [/tex]
