Tóm tắt :
\(m_1+m_2=6kg\)
\(t=50^oC\)
\(t_1=70^oC\)
\(t_2=15^oC\)
\(c_1=2500J/kgK\)
\(c_2=4200J/kgK\)
\(m_1=?kg\)
\(m_2=?kg\)
GIẢI :
Ta có : \(m_1+m_2=6kg\)
\(m_1=6-m_2\) (1)
Ta có : \(Q_{thu}=Q_{tỏa}\)
\(\Rightarrow m_1.c_1.\left(t_1-t\right)=m_2.c_2.\left(t-t_2\right)\)
\(\Rightarrow m_1.2500\left(70-50\right)=m_2.4200\left(50-15\right)\)
\(\Rightarrow m_1.50000=m_2.147000\)
\(\Rightarrow m_2=\dfrac{50000m_1}{147000}\) (2)
Thay (1) vào (2) ta được :
\(50000\left(6-m_2\right)=147000m_2\)
\(\Leftrightarrow300000-50000m_2=147000m_2\)
\(\Leftrightarrow197000m_2=300000\)
\(\Leftrightarrow m_2=\dfrac{300000}{197000}\approx1,52\left(kg\right)\)
Thay \(m_2\) vào (1) ta có :
\(m_1=6-m_2=6-1,52=4,48\left(kg\right)\)
