*Thả vào bình 1:

=>Qtoa(sat)1=m460.(t−4,2)(J)=>Qtoa(sat)1=m460.(t−4,2)(J)

=>Qthu(nuoc)1=5.4200.4,2=88200(J)=>Qthu(nuoc)1=5.4200.4,2=88200(J)

=>460m(t−4,2)=88200(1)=>460m(t−4,2)=88200(1)

*thả vào bình 2:

=>Qtoa(sat)2=m.460(t−28,9)(J)=>Qtoa(sat)2=m.460(t−28,9)(J)

=>Qthu(nuoc)2=4.4200.(28,9−25)=65520(J)=>Qthu(nuoc)2=4.4200.(28,9−25)=65520(J)

=>460m(t−28,9)=65520(2)=>460m(t−28,9)=65520(2)

(1)(2)=>hệ pt: {460m(t−4,2)=88200460m(t−28,9)=65520{460m(t−4,2)=88200460m(t−28,9)=65520

<=>{460mt−1932m=88200460mt−13294m=65520<=>{460mt−1932m=88200460mt−13294m=65520

=>11362m=22680=>m≈2kg(3)=>11362m=22680=>m≈2kg(3)

thế(3) vào(1)=>460.2(t−4,2)=88200=>t=100oC