a)
[tex]Dane:\\v_{o} = 0\\t = 3 \ s\\v = 6\frac{m}{s}\\Szukane:\\a = ?\\\\\\a = \frac{\Delta v}{t} = \frac{v-v_{o}}{t} = \frac{v}{t} = \frac{6\frac{m}{s}}{3 \ s}\\\\\boxed{a = 2\frac{m}{s^{2}}}[/tex]
b)
[tex]Dane:\\a = 2\frac{m}{s^{2}}\\t = 3 \ s\\Szukane:\\s_1 = ?\\\\\\s = \frac{1}{2}at^{2}\\\\s_1 = \frac{1}{2}\cdot2\frac{m}{s^{2}}\cdot(3 \ s)^{2}\\\\\boxed{s_1 = 9 \ m}[/tex]
c)
[tex]s_1 = 9 \ m\\\\s_2=v\cdot t =6\frac{m}{s}\cdot7 \ s = 42 \ m\\\\s = s_1 + s_2 = 9 \ m + 42 \ m\\\\\boxed{s = 51 \ m}[/tex]
