A、B两正方体实心金属块放在水平地面上,它们的边长之比为1:3,对地面的压强之比为2:3,则两金属的密度之比是(  ) A.4:9 B.9:4 C.1:2 D.2:1

问题描述:

A、B两正方体实心金属块放在水平地面上,它们的边长之比为1:3,对地面的压强之比为2:3,则两金属的密度之比是(  )
A. 4:9
B. 9:4
C. 1:2
D. 2:1

PA
PB
=
2
3
hA
hB
=
1
3

∴根据p=
F
S
=
G
S
=
mg
S
=
ρSgh
S
=ρgh,
可得
PA
PB
=
ρAghA
ρAghB
=
ρAhA
ρBhB
=
ρA×1
ρB×3
=
2
3

ρA
ρB
=
2
1

故选D.