1.
[tex]dane:\\t = 5 \ s\\v = 36\frac{km}{h} = 36\cdot\frac{1000 \ m}{3600 \ s} = 10\frac{m}{s}\\szukane:\\s = ?\\\\s = v\cdot t\\\\s = 10\frac{m}{s}\cdot5 \ s\\\\s = 50 \ m[/tex]
2.
[tex]dane:\\s = 12 \ km = 12 \ 000 \ m\\v = 15\frac{m}{s}\\szukane:\\t = ?\\\\t = \frac{s}{v}\\\\t = \frac{12000 \ m}{15\frac{m}{s}} = 800 \ s = 13 \ min \ i \ 20 \ s[/tex]
3.
[tex]dane:\\s = 4 \ km\\t = 2 \ min = \frac{2}{60} \ h = \frac{1}{30} \ h\\szukane:\\v = ?\\\\v = \frac{s}{t}\\\\v = \frac{4 \ km}{\frac{1}{30}h} = 120\frac{km}{h}[/tex]