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# Physics/hello

Question

image of question
QUESTION: hello
my question is about mechanics i think!

A tanker full of a liquid, is static on a straight road with no friction. Outlet pipe of the tanker is on down and corner of it and Its closed by a stopper.
Describe movement (motion) of tanker after we suddenly open the outlet pipe!

http://prntscr.com/27o8cp
(its same image that i attached)

and sorry if my english is weak!

ANSWER: Well, I'd say that realistically that would depend on whether or not the water washes up against the wheels.  But if you're reducing it to a fundamental physics problem the tank will shift to the right by a certain distance.  The distance will depend on the relative masses of the tank and the water, when the water is gone the tank will stop moving.  The center of mass will remain the same.

---------- FOLLOW-UP ----------

QUESTION: there is a basic question
you know that the tanker is full of water . so there is no air in the tanker
when water is coming out of the outlet some bubbles of air may go into the tanker and fill the emptied space
when a bubble of air reaches the surface of water , makes two waves . One toward the left side of the tanker and the other toward the right side
these two waves have energy and when they hit the frame of the tanker , they cause a force toward the frame of the tanker
these two waves are mechanical waves and they need some time to reach the frame
as we know that the outlet is closer to the left side of the frame , so the left wave will reach the frame sooner and cause a motion to the left until the right wave reach to the right side of frame
when the right wave hits the right partition of tanker causes a force in the opposite direction and makes the tanker stop .
is there any similar action in the motion of tanker according to your experience ?
according to the pressure of the atmosphere is it possible that water never comes out of the outlet ?
please explain the detailed condition of the tanker and exit of water from the outlet if its possible

I was simply talking about the overall net motion of the tank.  The bubbles would cause a lot of random waves.  That might cause some shaking, yes, as the waves slosh around and the water in the tank is displaced, but it would probably be extremely weak and random.  The drawing showed a pipe hanging straight down, so that would let bubbles in.  If the pipe curved upwards, then it might stop the water, but not as drawn.  As to what would happen to the tanker, that was described in plenty of detail in my first response.

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#### Dr. Stephen O. Nelson

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I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.

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