[tex]dane:\\m = 6 \ kg\\v_1 = 5\frac{m}{s}\\t = 12 \ s\\v_2 = 40\frac{m}{s}\\szukane:\\F = ?\\\\Rozwiazanie:\\\\F = m\cdot a\\\\ale:\\a = \frac{\Delta v}{t} = \frac{v_2-v_1}{t}, \ zatem\\\\F = m\cdot\frac{v_1-v_1}{t}\\\\F = 6 \ kg\cdot\frac{(40-5)\frac{m}{s}}{12 \ s}\\\\\underline{F = 17,5 \ N}[/tex]
