wykorzystam bilans cieplny Cw mp (Tk - Tpp)= Cw mo (Tpo-Tk) mp Tk- mp Tpp= mo Tpo- mo Tk mp Tk + mo Tk= mo Tpo+ mp Tpp Tk (mo + mp)= mo Tpo+ mp Tpp Tk=mo Tpo+ mp Tpp/mo + mp Tk= 20 x 80 + 10 x 20/ 20 + 10 Tk= 1600 + 200/30 Tk= 1800/30 Tk=60 C Temperatura końcowa wody wyniesie 60 C.
obliczam masę wody : V = 10 dm³ = 10000 cm³ d = 1 g/cm³ m = ? d = m / V m = V * d m = 1000 cm³ * 1 g/cm³ m₁ = 10000 g = 10 kg m₂ = 20000 cm³ * 1 g/cm³ m₂ = 20 kg T₁ = 20⁰C T₂ = 80⁰C T = ? zasad bilansu cieplnego : Q₁ = Q₂ m₁ * cw * ΔT₁ = m₂ * cw *ΔT₂ ; dzielę obustronnie przez cw ( bo obie substamcje to woda) m₁ * ΔT₁ = m₂ *ΔT₂ ; 10 kg * ( T - 20⁰C ) = 20 kg * ( 80⁰C - T ) 10 kg * T - 200 kg * ⁰C = 1600 kg * ⁰C - 20 kg * T 10 kg * T + 20 kg * T = 1600 kg * ⁰C + 200 kg * ⁰C T ( 10 kg + 20 kg ) = 1800 kg * ⁰C T = 1800 kg * ⁰C/ 30 kg T = 60⁰C
