用手將一個(gè)質(zhì)量500g,邊長(zhǎng)10cm 的正方體物快浸沒(méi)于手中,使物快上表面離水面20cm

物理人氣：426 ℃時(shí)間：2019-09-22 06:06:56

優(yōu)質(zhì)解答

正方體物快下表面受到傷害的壓強(qiáng)

P =ρgh =ρg(0.1m+0.2m) = 1000kg/m^3 * 10N/kg * 0.3m = 3000 N/m^2
2.正方體物快上下表面受到的壓力差
壓強(qiáng)差P =ρgh =ρg(0.2m) = 2000N/m^2
壓力差 2000N/m^2* 0.2^2 = 80N
3.放手后,正方體物快最終靜止時(shí)受到的浮力(g取10N/kg)2. 壓力差 = 壓強(qiáng)差*表面積 = 2000N/m^2* 0.1m^2 = 40N 3 靜止時(shí)浮力 = 重力 = mg = 0.5kg * 10N/kg = 5N