Question

A rectangular trough, 2.0 m long, 0.50 m wide, and 0.50 m deep, is completely full of water. One end of the trough has a small drain plug right at the bottom edge.
When you pull the plug, at what speed does water emerge from the hole? (in m/s)

Hint: V = sqrt (2 g H

I just don't know where to start.

Answer 1

the hint is the answer

v = sqrt (2*9.8*.5)

from
m g h = (1/2)mv^2
is
2 g h = v^2
the potential energy of a chunk of water at the surface is its kinetic energy exiting at the bottom
you can do it with Bernouli if you want to get sophisticated :)

p + rho g h + (1/2) rho v^2 = constant

at water surface p and v are 0
at bottom exit, p and h are 0

Answer 2

Thank you