①ρB=mB/VB 1分 =13.5千克/27×10-3米3=0.5×103千克/米3 1分 ②pA=FA/SA=ρAghA 1分 =2×103千克/米3×9.8牛/千克×0.2米=3920帕 1分 ③若pA′=pB′ FA′/SA=FB′/SB ρAg(VA-V)/SA=ρBg(VB-V)/SB 1分 2×103千克/米3×(8×10-3米3-V)/0.04米2 =0.5×103千克/米3×(27×10-3米3-V)/0.09米2 V=5.625×10-3米3 1分 若pA′>pB′ V<5.625×10-3米3 1分 若pA′<pB′ V>5.625×10-3米3 |