Do wody o masie 5kg i temperaturze 20 stopni dolano 5kg nafty o temp. 40 stopni. Oblicz temperature powstałej mieszaniny.

[latex]m_{1}=5 [kg]\\T_{1}=20 [^{o}C]\\m_{2}=5 [kg]\\T_{2}=40 [^{o}C]\\c_{w_{1}}=4200 [frac{J}{kgcdot ^{o}C}]\\c_{w_{2}}=2100 [frac{J}{kgcdot ^{o}C}][/latex] Wyznaczamy temperaturę końcową mieszaniny: [latex]Q_{1}+Q_{2}=0\\m_{1}c_{w_{1}}(T_{k}-T_{1})+m_{2}c_{w_{2}}(T_{k}-T_{2})=0\\T_{k}=frac{m_{1}c_{w_{1}}T_{1}+m_{2}c_{w_{2}}T_{2}}{m_{1}c_{w_{1}}+m_{2}c_{w_{2}}}=26frac{2}{3} [^{o}C][/latex]