> 物理 >
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
人气:111 ℃ 时间:2019-08-18 23:01:41
解答
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.
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