A.
B.
C.
D.
[单选题]A.1cmB.2cmC.2.5cmD.3cmE.4cm
[单选题]A.1A,50Hz,30°B.1A,100Hz,-30°C.0.707A,100Hz,30°D.0.707A,50Hz,30°
[单选题]A.层流B.过渡流C.无法判断D.湍流流动
[单选题]A.0B.1/2C.1/4D.-1/2E.2010
[单选题]A.③④B.①③C.①②D.②④E.②③
[单选题]A.9/10B.4C.-4D.13/16E.无法确定
[单选题]A.1,3B.1,2C.-1,3D.-1,2E.-1,-3