1.
[tex]Dane:\\S = 4 \ dm^{2} = 0,04 \ m^{2}\\F = 19,6 \ N\\Szukane:\\p = ?\\\\Rozwiazanie\\\\p = \frac{F}{S}\\\\p = \frac{19,6 \ N}{0,04 \ m^{2}}\\\\\boxed{p = 490 \ Pa}[/tex]
2.
[tex]Dane:\\m = 5 \ kg\\a = 5 \ cm = 0,05 \ m\\S = a^{2} = (0,05 \ m)^{2} = 0,0025 \ m^{2}\\g = 10\frac{N}{kg}\\Szukane:\\p = ?\\\\Rozwiazanie\\\\p = \frac{F}{S}\\\\ale \ \ F = m\cdot g = 5 \ kg\cdot10\frac{N}{kg} = 500 \ N\\\\p = \frac{500 \ N}{0,0025 \ m^{2}}\\\\\boxed{p = 200 \ 000 \ Pa = 200 \ kPa}\\\\(1 \ kPa = 1000 \ Pa)[/tex]
3.
[tex]Dane:\\p = 2,5 \ kPa = 2,5\cdot10^{3} \ Pa = 2,5\cdot10^{3} \ \frac{N}{m^{2}}\\F = 0,5 \ MN = 0,5\cdot10^{6} \ N = 5\cdot10^{5} \ N\\1 \ m^{2} = 100 \ dm^{2}\\Szukane:\\S = ?\\\\Rozwiazanie\\\\p = \frac{F}{S} \ \ /\cdot S\\\\p\cdot S = F \ \ /:p\\\\S = \frac{F}{p}\\\\S = \frac{5\cdot10^{5} \ N}{2,5\cdot10^{3} \ Pa} = \frac{5\cdot10^{5} \ N}{2,5\cdot10^{3} \ \frac{N}{m^{2}}}\\\\S = 2\cdot10^{2} \ m^{2} = 200 \ m^{2}\\\\1 \ m^{2} = 100 \ dm^{2}\\\\S = 200 \ m^{2} = 200\cdot100 \ dm^{2}[/tex]
[tex]\boxed{S = 20 \ 000 \ dm^{2}}[/tex]
