7.
[tex]dane:\\a = 0,5\frac{m}{s^{2}}\\v_1 = 10\frac{km}{h}\\v_2 = 46\frac{km}{h}\\szukane:\\t = ?\\\\Rozwiazanie\\\\a = \frac{\Delta v}{t} \ \ \rightarrow \ \ t = \frac{\Delta v}{a}\\\\\Delta v =v_2 - v_1 = (46-10)\frac{km}{h} = 36\frac{km}{h} = 36\cdot\frac{1000 \ m}{3600 \ s} = 10\frac{m}{s}\\\\t = \frac{10\frac{m}{s}}{0,5\frac{m}{s^{2}}} = 20 \ s[/tex]
8.
[tex]dane:\\v_{o} = 0\\t = 5 \ s\\v = 36\frac{km}{h} = 10\frac{m}{s}\\szukane:\\s = ?\\\\Rozwiazanie\\\\Dla \ \ v_{o} = 0\\\\s = \frac{1}{2}at^{2}\\\\a = \frac{v}{t}\\\\s = \frac{1}{2}\cdot\frac{v}{t}\cdot t^{2}\\\\s = \frac{1}{2}vt\\\\s = \frac{1}{2}\cdot10\frac{m}{s}\cdot5 \ s\\\\s = 25 \ m[/tex]
