Đáp án:
${{t}_{cb}}={{47}^{0}}C$
Giải thích các bước giải:
${{m}_{Al}}=8,97kg;{{t}_{Al}}={{91}^{0}}C;{{m}_{Cu}}=2,64kg;{{m}_{nc}}=3,52kg;{{t}_{0}}={{25}^{0}}C;$
Khi cân bằng nhiệt xảy ra:
$\begin{align}
& {{Q}_{toa}}={{Q}_{thu}} \\
& \Leftrightarrow {{m}_{Al}}.{{c}_{Al}}.({{t}_{Al}}-{{t}_{cb}})=\left( {{m}_{Cu}}.{{c}_{Cu}}+{{m}_{nc}}.{{c}_{nc}} \right).({{t}_{cb}}-{{t}_{0}}) \\
& \Leftrightarrow 8,97.880.(91-{{t}_{cb}})=(2,64.380+3,52.4200).({{t}_{cb}}-25) \\
& \Rightarrow {{t}_{cb}}={{47}^{0}}C \\
\end{align}$