第八章单元测试
- A 2-in. diameter shaft is supported by two sleeves, each of length = 2 in. The internal diameter of the sleeves is 2.1 in. The radial space between the shaft and the sleeves is filled with an oil of viscosity = 8 × 10-3 lb-s/ft2. If the shaft is rotated at a speed of 600 rpm, the viscous torque (ft-lb) on the shaft is most nearly （ ）。
- “The pressure at a point in a fluid at rest, or in motion, is independent of direction as long as there are no shearing stresses present”This important result is known as
- The force amplification can be realized by increasing the acting area. True or False? （ ）
The pressure amplification can be realized by increasing the acting area. （ ）
- How to reduce hydraulic shock? （ ）。
A:6.40
B:0.15
C:0.64
D:3.20
答案:0.15
A:对 B:错
A:对 B:错
A:Increase the diameter of the pipeline
B:Extend the time of valve closing
C:shorten the length of the pipeline as far as possible
D:Limit pipeline flow rate
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