[tex]Dane:\\F_{g} = 40 \ N\\F_{z} = 15 \ N\\d = 1000\frac{kg}{m^{3}} \ - \ gestosc \ wody\\g = 10\frac{N}{kg}\\Szukane:\\a) \ F_{w} = ?\\b) \ V = ?\\\\Rozwiazanie\\\\a)\\F_{w} = F_{g} - F_{z}\\\\F_{w} = 40 \ N -15 \ N\\\\\boxed{F_{w} = 25 \ N}[/tex]
[tex]b)\\F_{w} = d\cdot g\cdot V \ \ /:(d\cdot g)\\\\V = \frac{F_{w}}{d\cdot g}\\\\V = \frac{25 \ N}{1000\frac{kg}{m^{3}}\cdot10\frac{N}{kg}}\\\\\boxed{V = 0,0025 \ m^{3} = 2,5 \ dm^{3} = 2,5 \ l}[/tex]
