比热容练习题想得到6kg50℃的温水,而把25℃的冷水和100℃的开水混合,问需用冷丶开水各多少?················_物理解答

比热容练习题
想得到6kg50℃的温水,而把25℃的冷水和100℃的开水混合,问需用冷丶开水各多少?·········································································································

人气：298 ℃　时间：2020-03-24 11:02:47

解答

设用xkg冷水,（6-x）kg热水
Q末=Cm10△t=4.2X10^3X6X50=1.26X10^6J
Q冷=Cx△t=x`1.05X10^5J
Q热=C（6-x）△t=(6-x)`4.2X10^5
Q热+Q冷=Q末
x=4kg
6-x=2kg