推 shcyril :U-tube 09/22 15:26
→ goaremdy :U型管 09/22 15:27
→ i19hasen :太棒啦~~~:DD 感謝!!! 下回補推回來XD 09/22 23:11
其實我也不確定我的對不對耶囧
3-87
It is said that Archimedes discovered his principle during a bath while
thinking about how he could determine if King Hiere's crown was actually made
of pure gold. While in the bathtub, he conceived the idea that he could
determine the average density of an irregularly shaped object by weighing it
in air and also in water. If the crown weighed 3.20 kgf(= 31.4N) in air and
2.95 kgf(= 28.9N) in water, determine if the crown is made of pure gold. The
density of gold is 19300 kg/m^3. Discuss how you can solve this problem
without weighing the crown in water but by using an ordinary bucket with no
calibration for volume. You may weigh anything in air.
3-109
A 3-m-diameter, 7-m-long cylindrical tank is completed filled with water.
The tank is pulled by a truck on a level road with the 7-m-long axis being
horizontal. Determine the pressure difference between the front and back ends
of the tank along a horizontal line when the truck (a) accelerates at 3m/s^2
and (b) decelerates at 4 m/s^2.
3-128
Consider a U-tube filled with mercury except the 18-cm-high portion at
the top, as shown in Fig. P3-128. The diameter of the right arm of the U-tube
is D = 2 cm, and the diameter of the left arm is twice that. Oil with a
specific gravity of 2.72 is poured into the left arm, forcing some mercury
from the left arm into the right one. Determine the maximum amout of oil that
can be added into the left arm.
Fig. P3-128 http://ppt.cc/8JSA
3-141
A semicircular 30-ft-diameter tunnel is to be built under a 150-ft-deep,
800-ft-long lake, as shown in Fig. P3-141. Determine the total hydrostatic
force acting on the roof of the tunnel.
Fig. P3-141 http://ppt.cc/qSO@
3-142
A 50-ton, 6-m-diameter hemispherical dome on a level surface is filled
with water, as shown in Fig. P3-142. Someone claims that he can lift this dome
by making use of Pascal's law by attaching a long tube to the top and filling
it with water. Determine the required height of water in the tube to lift the
dome. Disregard the weight of the tube and the water in it.
Fig. P3-142 http://ppt.cc/0orJ
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