[tex]Dane:\\m = 2 \ 400 \ g = 2,4 \ kg\\S = 20 \ cm\cdot 40 \ cm = 800 \ cm^{2} = 0,08 \ m^{2}\\g = 10\frac{N}{kg}\\Szukane:\\p = ?\\\\\\p = \frac{F}{S}\\\\F = m\cdot g = 2,4 \ kg\cdot10\frac{N}{kg} = 24 \ N\\\\p =\frac{24 \ N}{0,08 \ m^{2}}\\\\\boxed{p = 300 \ Pa}[/tex]
