某水泵运行时进口压力为0.05Mpa,排出口压力为0.25Mpa,则水泵的压头为()。
A.20mH2O
B.25mH2O
C.30mH2O
D.35mH2O
参考答案:A
简述教育发展战略与教育规划的关系。
The force resulting from the earth’s rotation that causes winds to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere is called().
A.pressure gradient
B.Coriolis effect
C.aurora borealis
D.ballistic deflection