[tex]Dane:\\a = 40 \ cm = 0,4 \ m\\b = 0,5 \ m\\S = a \times b = 0,4 \ m \times 0,5 \ m = 0,2 \ m^{2}\\p = 800 \ hPa = 800\times 100 \ Ps = 80 \ 000 \ Pa = 80 \ 000 \ \frac{N}{m^{2}}\\Szukane:\\F = ?\\\\Rozwiazanie\\\\p = \frac{F}{S} \ \ /\cdot S\\\\F = p\times S\\\\F = 80 \ 000 \ Pa\times 0,2 \ m^{2} = 80 \ 000 \ \frac{N}{m^{2}}\times 0,2 m^{2}}\\\\\boxed{F = 16 \ 000 \ N = 16 \ kN}\\\\(1 \ kN = 1000 \ N)[/tex]
