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【简答题】
如图所示，用高位槽向用户送水，所用管路规格为ø108×4mm。管路中装有一U形管压差压力表PA和PB，Z0=20.4m，压差计的指示液密度为13 600kg/m3，试问当打开阀门V时，压力表PB读数为0.072MPa，若L1=L2=5m，R=10mm，摩擦系数为0.021，则管路系统阻力及管长与管路局部阻力当量长度之和为∑l+le= m。（注：水的密度为1000 kg/m3）【图片】
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皮皮学刷刷变学霸
举一反三
【多选题】Which two statements are correct about Layer 2 broadcast frames?（）
A.
Layer 2 broadcast frames are processed by all devices on the same VLAN
B.
Layer 2 broadcast frames are are discarded by routers that connect to multiple VLANs
C.
Layer 2 broadcast frames are relayerd by routers to all connected VLANs
D.
Layer 2 broadcast frames are relayed by switches to devices on the same VLAN
【单选题】Panting frames are located in the ______.
A.
after double bottoms
B.
centerline tanks on tankers
C.
fore and after peaks
D.
forward double bottoms
【单选题】Panting frames are located in the ().
A.
After double bottoms
B.
Centerline tanks on tankers
C.
Fore and after peaks
D.
Forward double bottoms
【单选题】Panting frames are located in the（）.
A.
after double bottoms
B.
centerline tanks so tankships
C.
fore and after peaks
D.
forward double bottoms
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