(1)p1=ρgh1=1.0×103kg/m3×10N/kg×0.2m=2×103Pa;
(2)∵浸没F浮=ρgV排1=ρgVB=1.0×103kg/m3×10N/kg×50×10-6m3=0.5N,
F拉=G-F浮=3.9N-0.5N=3.4N,
(3)V水=Sh1=500×10-4m2×0.2m=0.01m3,
F浮A=ρgV排2=1.0×103kg/m3×10N/kg×640×10-6m3=6.4N,
G进水=F浮A+F浮-GA-GB=6.4N+0.5N-2N-3.9N=1N,
G进水=ρgV进水=1.0×103kg/m3×10N/kg×V进水,
解得V进水=1.0×10-4m3,
V水2=V水-V进水=0.01m3-1.0×10-4m3=99×10-4m3,
玻璃杯A最终漂浮,
F浮A2=GA+G进水=1N+2N=3N,
F浮A2=ρgV排3=1.0×103kg/m3×10N/kg×V排3,
解得V排3=3×10-4m3,
h2==
99×10?4m3+3×10?4m3+50×10?6m3
|
500×10?4m2
|
=0.205m,
p2=ρgh2=1.0×103kg/m3×10N/kg×0.205m=2.05×103Pa.
答:(1)没有放入玻璃杯和铁块时水对容器底部的压强为2×103Pa;
(2)A、B两物体在水中静止时细线对铁块B的拉力为3.4N;
(3)水对容器底部的压强为2.05×103Pa.