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1. |
When deriving the Bernoulli's equation,
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we have ONLY assumed that the flow is steady. |
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we have ONLY assumed that the fluid has no viscosity. |
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we have ONLY assumed that fluid is imcompressible. |
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all of the above are assumed. |
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none of the above is assumed. |
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2. |
The figure shows the motion of air around the wing of an airplane. Which of the followings is correct?
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The pressure is higher and the air flow is faster at the top of the airfoil |
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The pressure is lower and the air flow is faster at the top of the airfoil |
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The pressure is higher and the air flow is slower at the top of the airfoil |
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The pressure is lower and the air flow is slower at the top of the airfoil |
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The pressure and the air flow at the top of the airfoil is the same as those on the lower side |
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3. |
A pipe has a broad opening and a narrow ending.
Water now flows through the pipe from the opening
of cross section area
4 cm2 to the end of cross section area 2 cm2.
If water flows at a speed of 3 m/s at the opening of the pipe, then the speed at the end is |
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2 m/s |
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3 m/s |
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4 m/s |
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5 m/s |
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6 m/s |
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4. |
An incompressible fluid flows through a pipe with cross section area
50 cm2 at a speed of 20 m/s. The middle part of the pipe splits up
into two smaller pipes and their cross section areas are 20 cm2 and
40 cm2, respectively.
If the speed of fluid at the broader side is 20 m/s, the speed at the narrower side is |
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5 m/s |
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10 m/s |
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15 m/s |
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20 m/s |
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40 m/s |
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5. |
The speed of the air flow on the upper surface of
an airplane's wing is 150 m/s and on the lower surface is 120 m/s. If the density of air is
1.2 kg/m3, then the difference in pressure between the two surfaces
is |
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2430 Pa |
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4860 Pa |
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7290 Pa |
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9720 Pa |
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cannot be determined |
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6. |
A typhoon is blowing at a speed of 35 m/s towards the roof of a house,
given that the area of the roof is 100 m2 and the density of air is 1.2 kg/m3,
then the lift on the roof is |
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367.5 N |
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735 N |
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36750 N |
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61250 N |
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73500 N |
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7. |
The figure shows a Pitot tube that can measure flow velocity. If h1 = 2 cm, h2 = 5 cm, then what is the flow velocity v? (g = 9.8 m/s2) |
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77 cm/s |
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59 cm/s |
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7.7 cm/s |
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5.9 cm/s |
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11 cm/s |
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8. |
The figure shows a ball with top spin.
Which of the following statements is/are correct?
- The flow velocity of air on the top of the ball is greater than that below the ball.
- The pressure on the top is greater than that below the ball.
- The pressure difference on the ball makes it drop faster than expected.
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I |
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II |
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III |
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I and II |
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II and III |
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9. |
An incompressible fluid with density  flows through the pipe as shown in the figure. If the cross section area A of the pipe is uniform, what is the flow velocity v2 at point B?
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10. |
Referring to Q9, what is the pressure
P2 at point B? |
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