[حسين14]

سلام عليكم

اذا كان من الممكن من الاساتذة حل المسائل با التفصيل سوف اكون لهو من الشاكرين

Fluid Mechanic
_



1) A container has a vertical tube, whose inner radius is 13.00 mm, connected to it at its side. An
unknown liquid reaches level A in the container and level B in the tube􀁎level A being 5.0 cm
higher than level B. The liquid supports a 20.0-cm high column of oil, between levels B and C,
whose density is 730 kg/m3. In Fig. 14.1, the mass of the oil, in grams, is closest to:
1)
A) 150 B) 230 C) 77 D) 310 E) 390


2) A 3.4-kg solid sphere, made of metal whose density is 4600 kg/m3, is suspended by a cord. The
density of water is 1000 kg/m3. When the sphere is immersed in water, the tension in the cord is
closest to:
2)
A) 37 N B) 41 N C) 33 N D) 30 N E) 26 N



3) What force does the water exert (in addition to that due to atmospheric pressure) on a submarine
window of radius 94 cm at a depth of 8000 m in sea water (density 1025 kg/m3)?
3)
A) 2.23 × 108 N
B) 1.12 × 108 N
C) 7.10 × 107 N
D) 2.23 × 1012 N
E) 1.12 × 1012 N
1



4) A pressurized cylindrical tank, 5.0 m in diameter, contains water that emerges from the pipe at
point C, with a velocity of 12 m/s. Point A is 10 m above point B and point C is 3 m above point B.
The area of the pipe at point B is 0.06 m2 and the pipe narrows to an area of 0.04 m2 at point C.
Assume the water is an ideal fluid in laminar flow. The density of water is 1000 kg/m3. In Fig. 14.3,
the rate at which the water level is falling in the tank, in mm/s, is closest to:
4)
A) 13 B) 28 C) 17 D) 24 E) 21



5) At a depth d in the ocean, the gauge pressure is p. The depth at which the gauge pressure would be
three times as great is:
5)
A) 6d B) 3 d C) 9d D) 6 d E) 3d



6) Water is flowing in a horizontal pipe of diameter d. If you want to change the diameter of this pipe
so that the speed of the water would be half as great as it was, the new diameter should be:
6)
A) d/ 2 B) d/4 C) 2d D) d/2 E) d 2



7) The Bernoulli effect is described by the equation
p1 + 1/2􀎕v21 + 􀎕gh1 = p2 + 1/2r22 + 􀎕gh2
The origin of this relation is that it is a statement of
7)
A) the continuity principle for fluids.
B) the conservation of linear momentum.
C) Newton's Third Law, i.e equal action and reaction.
D) the conservation of energy for a moving fluid.
E) F = ma as applied to a fluid


.
8) A solid wooden sphere of density 0.650 g/cm3 is released inside a liquid of density 1.15 g/cm3 at a
depth of 1.50 m. The liquid has no appreciable viscosity. Just after it is released, the acceleration of
the sphere is closest to:
8)
A) 4.26 m/s2 downward
B) 7.54 m/s2 downward
C) 7.54 m/s2 upward
D) 4.26 m/s2 upward
E) It is impossible to tell without knowing the radius of the sphere.
2

[ALZAHRANI]

سؤال 3 جوابه c
باستخدام قانونالضغط اللي هو القوي مقسومة على المساحة
وبمان الكثافة موجودة و الارتفاع نجد من قانون الضغط الاخر اللي هو الضغط يساوي الارتفاع مضروب في الكثافة نستنتج منه الضغط ومن نرجع للقانون الاول ونطلع القوة القريبة من الجواب c

[mahmoud khodary]

1 - Ans. c

mass = volume * density
volume = area * height
area = pi * r^2
m = 730 * 3.14 * 0.013^2 * 0.2
m = 77.48 *10^-3 kg
m = 77.48 g

2 - Ans. c

the density of the solid sphere is much higher than the density of water so it goes down to the bottom
and the tension in the cord is equal to the weight of the solid sphere
W = T = m *g = 3.4 *9.81
T = 33.33 N

3 - Ans. a

pressure = density * gravitational acceleration * column height
p = 1025 * 9.81 * 8000
p = 80442 Pa
force = pressure * area
area = pi * r^2 = 3.14 * 0.94^2 = 2.77 m^2
F = 80442 * 2.77
F = 2.23 *10^8 N