標題:
F.3-Physics Heat
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發問:
Given that:(1).the specific heat capacity of tea=3900 J kg-1 ℃-1;(2).the specific heat capacity of coffee=3200 J kg-1 ℃-1;(3).the specific heat capacity of milk=3500 J kg-1 ℃-1.0.5kg of tea at 45 ℃,0.2kg of coffee at 85 ℃ and 0.025kg of milk at 25 ℃ are mixed together .Assume there is no heat lost to the... 顯示更多 Given that: (1).the specific heat capacity of tea=3900 J kg-1 ℃-1; (2).the specific heat capacity of coffee=3200 J kg-1 ℃-1; (3).the specific heat capacity of milk=3500 J kg-1 ℃-1. 0.5kg of tea at 45 ℃,0.2kg of coffee at 85 ℃ and 0.025kg of milk at 25 ℃ are mixed together .Assume there is no heat lost to the surroundings.Find the final T ℃.
最佳解答:
(1).the specific heat capacity of tea=3900 J kg-1 ℃-1; (2).the specific heat capacity of coffee=3200 J kg-1 ℃-1; (3).the specific heat capacity of milk=3500 J kg-1 ℃-1. 0.5kg of tea at 45 ℃,0.2kg of coffee at 85 ℃ and 0.025kg of milk at 25 ℃ are mixed together .Assume there is no heat lost to the surroundings.Find the final T ℃. 設混合後的溫度為 T，因為主要是茶和咖啡混合，所以溫度應在45℃和85℃之間。 因此放熱的是咖啡 E1 = m1c1ΔT1 = 0.2 x 3200 x (85 – T) = 54400 – 640T 吸熱的有茶及奶 茶的吸熱 E2 = m2c2ΔT2 = 0.5 x 3900 x (T - 45) = 1950T – 87750 奶的吸熱 E2 = m3c3ΔT3 = 0.025 x 3500 x (T - 25) = 87.5T – 2187.5 因為沒有其他能量的吸收及散失則吸熱 = 放熱 E2 + E3 = E1 1950T – 87750 + 87.5T – 2187.5 = 54400 – 640T 2677.5T = 144337.5 T = 53.91℃ 最後溫度為53.91℃
其他解答:
我不肯定。 E=mcxT 0.5x45x3900+0.2x85x3200+0.025x25x3500 =144337.5 144337.5 / [ (3900+3200+3500)/3 ] =40.85 40.85 / (0.5+0.2+0.025) =56.345℃ the final T is 56.345℃
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