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## Homework Statement

A closed and elevated vertical cylindrical tank with diameter 2m contains water to a depth of 0.8m.

A circular hole is made at the bottom of the tank with diameter 0.2m.As the water drains from the tank, compressed air above the water in the tank maintains a gauge pressure of 5000Pa at the surface of the water.

Ignore viscosity.How much time does it take for all the water to drain from the tank?

## Homework Equations

Bernoulli's equation

Continuity equation

## The Attempt at a Solution

I have no idea how to approach a problem like this in general but here is what i thought:

I can calculate water flow through a small hole using

[tex]

dV/dt=A\upsilon

[/tex]

Now

[tex]

dt=dV/A\upsilon

[/tex]

and integrate both sides to get t.

Unfortunately, I get nowhere.Units do not match and so on.I don't know if this is even conceptually right.

Now a friend of mine says i should watch out for dh/dt rate, but I can't see how is that useful