[tex]dane:\\v_{o} = 5\frac{m}{s}\\t = 2,5 \ min = 2,5\cdot60 \ s = 150 \ s\\v=108\frac{km}{h} = 108\cdot\frac{1000 \ m}{3600 \ s} = 30\frac{m}{s}\\F = 12 \ N\\szukane:\\m = ?\\\\Rozwiazanie\\\\Z \ II \ zasady \ dynamiki\\\\a = \frac{F}{m} \ \ /\cdot m\\\\a\cdot m = F \ \ /:a\\\\m = \frac{F}{a}\\\\\\a = \frac{\Delta v}{t} = \frac{v-v_{o}}{t} = \frac{30\frac{m}{s}-5\frac{m}{s}}{150 \ s} = \frac{25\frac{m}{s}}{150 \ s} = \frac{1}{6}\frac{m}{s^{2}}[/tex]
[tex]m = \frac{12 \ N}{\frac{1}{6}\frac{m}{s^{2}}} = \frac{12 \ kg\cdot\frac{m}{s^{2}}}{\frac{1}{6}\frac{m}{s^{2}}} = 12\cdot6 \ kg = 72 \ kg[/tex]
Odp. Masa tego ciała m = 72 kg.
