[tex]dane:\\V = 4\ cm\times 6 \ cm\times 4 \ cm = 96 \ cm^{3} = 0,000096 \ m^{3}\\d = 21\frac{g}{cm^{3}} = 21\cdot\frac{\frac{1}{1000}kg}{\frac{1}{1000000 \ m^{3}}} = 21\cdot1000 \ \frac{kg}{m^{3}} = 21 \ 000 \ \frac{kg}{m^{3}}\\g = 10\frac{N}{kg}\\szukane:\\F_{w} = ?\\\\F_{w} = d\times g\times V\\\\F_{w} = 21000\frac{kg}{m^{3}}\times10\frac{N}{kg}\times0,000096 \ m^{3}\\\\F_{w} = 20,16 \ N[/tex]
