[tex]Dane:\\S_2 = 800 \ cm^{2}\\S_1 = 4 \ cm^{2}\\F_1 = 40 \ N\\Szukane:\\F_2 = ?\\\\\\\frac{F_1}{S_1} = \frac{F_2}{S_2}\\\\S_1\cdot F_2 = S_2\cdot F_2 \ \ /:S_1\\\\F_2 = \frac{S_2}{S_1}\cdot F_1\\\\F_2 = \frac{800 \ cm^{2}}{4 \ cm^{2}}\cdot 40 \ N\\\\F_2 = 200\cdot 40 \ N\\\\\boxed{F_2 = 8 \ 000 \ N}[/tex]
