Question

初二物理密度问题

甲乙两金属的密度分别为ρ甲，ρ乙，将等质量的甲乙两金属制成合金，则合金的密度为？要过程

Answer 1

设：甲乙的质量都为m
V甲=m/ρ甲
V乙=m/ρ乙
ρ合金=2m/(V甲+V乙)=2m/(m/ρ甲+m/ρ乙)=2ρ甲ρ乙/(ρ甲+ρ乙)

追问

2m/(m/ρ甲+m/ρ乙)=2ρ甲ρ乙/(ρ甲+ρ乙)这部如何转换？

追答

2m/(m/ρ甲+m/ρ乙)
分母通分：(m/ρ甲+m/ρ乙)=(mρ甲+mρ乙)/ρ甲ρ乙
2m除以它=2m乘以它的倒数
最后得：2mρ甲ρ乙/(mρ甲+mρ乙)

Answer 2

ρ合=M/V
=(m甲+m乙)/(v甲+v乙)
=2m甲/(m甲/ρ甲+m乙/ρ乙)
=2m甲/[m甲(ρ甲+ρ乙)/ρ甲ρ乙]
=2ρ甲ρ乙/(ρ甲+ρ乙)

Answer 3

ρ合=M/V
=(m甲+m乙)/(v甲+v乙)
=2m甲/(m甲/ρ甲+m乙/ρ乙)
=2m甲/[m甲(ρ甲+ρ乙)/ρ甲ρ乙]
=2ρ甲ρ乙/(ρ甲+ρ乙)

Answer 4

V甲=m/ρ甲，V乙=m/ρ乙
ρ合金=2m/(V甲+V乙）=2m/m/(ρ甲+ρ乙)*ρ甲*ρ乙=2ρ甲*ρ乙/(ρ甲+ρ乙)

Answer 5

设：甲乙的质量都为m
V甲=m/ρ甲
V乙=m/ρ乙
ρ2m/(m/ρ甲+m/ρ乙)
=2ρ甲*ρ乙/(ρ甲+ρ乙)

Answer 6

合成之后体积不会变的吗？