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A large tank is filled with water. The total pressure at the bottom is $$3.0atm$$. If a small hole is punched at the bottom, what is the velocity of efflux?

Solution:

A large tank is filled with water. The total pressure at the bottom is $$3.0atm$$. A small hole is punched at the bottom.
Pressure at the bottom due to water coloumn $$(3-1)atm$$ $$=2atm$$ $$=2\times 10^5 Pa$$

The equation for pressure is $$P=h\rho g$$
Hence, $$h=\frac{P}{\rho g}$$ $$=\frac{2\times 10^5}{1000g}$$ $$=\frac{200}{g}$$
Hence, velocity $$v=\sqrt{2gh}$$ $$=\sqrt{\frac{200}{2g}}$$ $$=20m/s$$