正方体物快下表面受到伤害的压强

P =ρgh =ρg(0.1m+0.2m) = 1000kg/m^3 * 10N/kg * 0.3m = 3000 N/m^2
2.正方体物快上下表面受到的压力差
压强差P =ρgh =ρg(0.2m) = 2000N/m^2
压力差 2000N/m^2* 0.2^2 = 80N
3.放手后,正方体物快最终静止时受到的浮力(g取10N/kg)2. 压力差 = 压强差*表面积 = 2000N/m^2* 0.1m^2 = 40N 3 静止时浮力 = 重力 = mg = 0.5kg * 10N/kg = 5N