①∵ρ=
,m V
∴mA=ρ水VA=1.0×103千克/米3×0.0004米3=0.4千克;
②FB=GB=mBg=0.64千克×9.8牛/千克=6.272牛,
pB=
=F S
=1568帕,6.272牛 0.004米2
③pA=pB,
ρ液=
=mB VB
=0.8×103千克/米3,0.64千克 0.004米2×0.2米
h水=
=V水 SA
=0.2米,0.0004米3
0.002米2
小张:分别在两个容器中抽出等体积液体,则有
ρ水g(0.2米-
)=ρ液g(0.2米-V 0.002米2
),V 0.004米2
解得V=1.38×10-4米3,所以小张的说法正确.
小李:分别在两个容器中加入等体积液体,则
ρ水g(0.2米+
)=ρ液g(0.2米+V 0.002米2
),V 0.004米2
解得V的数值为负数,所以小李的说法错误.
答:①A容器中水的质量为0.4千克.
②B容器对水平桌面的压强为1568帕.
③V=1.38×10-4米3,所以小张的说法正确,小李的说法错误.