Q吸=m水×c水×(t水末- t初)
Q放=m铁×c铁×(t初-t铁末)
已知Q放=Q初 t铁末=t水末=x
m水×c水×(t末- x)=m铁×c铁×(x-t初)
0.1kg*4.2*1000J/(kg*摄氏度)*(x-20摄氏度)=0.5kg*0.46*1000J/(kg*摄氏度)*(71-x摄氏度)
420x-8400=16330-230x
650x=24730
x=38.0461538...