[tex]dane:\\F = 250 \ kN = 250 \ 000 \ N\\p = k_{c} = 10 \ MPa = 10 \ 000 \ 000 \ Pa = 10 \ 000 \ 000 \ \frac{N}{m^{2}}\\S = a^{2}\\szukane:\\a = ?\\\\Rozwiazanie\\\\p = \frac{F}{S} \ \ \rightarrow \ \ S = \frac{F}{p}\\\\S = \frac{250 \ 000 \ N}{10 \ 000 \ 000 \ Pa}=\frac{25 \ N}{1000\frac{N}{m^{2}}}=0,025 \ m^{2}}\\\\a^{2} = 0,025 \ m^{2}}\\\\a= \sqrt{0,025 \ m^{2}}\\\\\underline{a\approx0,158 \ m}[/tex]