1.
[tex]Dane:\\v_1 = 40\frac{km}{h}\\v_2 = 60\frac{km}{h}\\t_1 = 50 \ s\\t_2 = 54 \ s\\Szukane:\\a = ?\\\\\\\Delta v = v_2-v_1 = (60-40)\frac{km}{h} = 20\frac{km}{h} = 20\cdot\frac{1000 \ m}{3600 \ s} = 5,(5)\frac{m}{s}= 5,56\frac{m}{s}\\\\\Delta t = t_2-t_1 = 54 \ s - 50 \ s = 4 \ s\\\\a = \frac{\Delta v}{\Delta t}=\frac{5,56\frac{m}{s}}{4 \ s}\\\\\boxed{a = 1,39\frac{m}{s^{2}}}[/tex]
2.
[tex]Dane:\\v_{p} = 5\frac{m}{s}\\a = 0,45\frac{m}{s^{2}}\\\Delta t = 20 \ s\\Szukane:\\v_{k}=?\\\\\\v_{k} = v_{p} + a\cdot \Delta t\\\\v_{k} = 5\frac{m}{s}+0,45\frac{m}{s^{2}}\cdot 20 \ s\\\\v_{k} = 5\frac{m}{s} + 9\frac{m}{s}\\\\\boxed{v_{k} = 14\frac{m}{s}}[/tex]
