恒定流是()。
A.流动随时间按一定规律变化的流动
B.流动中任意空间点的运动要素不随时间变化的流动
C.各过流断面的速度分布相同的流动
D.各过流断面的压强相同的流动
参考答案:B
Not until he finished his homework him to watch TV in the evening .
A.his mother allowed
B.his mother had allowed
C.did his mother allow
D.had his mother allowed
根据Stokes定律,混悬微粒沉降速率与之成反比的是()
A.混悬微粒的半径
B.混悬微粒的直径
C.混悬微粒的半径平方
D.分散介质的黏度
E.混悬微粒的密度