【简答题】试计算直径为60μm玻璃球在20℃水中自由沉降速度。已知玻璃球的密度为2500kg/m 3 ,水的密度为1000kg/m 3 ,水在20℃条件下的黏度为1.0×10 -3 Pa·s。
【单选题】Many types of lilies with ornate blossoms are cultivated for their beauty.
【单选题】Panda romance blossoms in capital
A.
1963: Kennedy assassination
B.
1969: 1st moon landing
C.
1983: panda mating in the US
D.
1989: the reunification of Germany
F.
2003: 1st Chinese space flight
【简答题】直径为1m的油管输送煤油,流量为2m 3 /s。在直径为10cm的水管中进行模型试验。煤油的相对密度为0.8,动力黏度为0.002Pa·s;水的动力黏度为0.001Pa·s。试求:
【单选题】______ is the best and most attractive food on Thanksgiving dinner table.
B.
Cranberry juice and squash
C.
Roast turkey and pumpkin pie
D.
Apples, oranges, chestnuts