Consider a bucket of water with two holes of equal area through which water is discharged. The water can flow out through hole ( B ), at the bottom, or through the down-spout, which begins at the top ( T ) and has its opening the same distance below the water level as the center of hole ( B).

  \-------------------------/
   \                       /
    \                     /__
     \                  T/--+|
      \                 /   ||
       \               /    ||
    ____\             /     ||
    -----\B          /      ||
          \---------/

Ignoring any friction effects, out of which opening will the water flow faster, and why?

(In reply to re(2): well well...well by Art M)

Assuming Art M's pipe is open at the top (not stated), then free fall of the ater column (that is, the water falls as one "connected slug of mass") could be approached if:

Friction is very low.  Friction in a pipe is propotional to the length, fluid type/properties, pipe meterial and "roughness" (size of minute surface irregualrities wrt the size of the pipe) and inversely proportional to the diameter (or equvalent if not circular).  Therfore a short, large dia, polished smooth pipe would have very low friction, and if the air could come in the top to replace the fluid in the pipe (no "glubbing" of air back up the pipe from the bottom), I would surmise you could get very close to 1g acceleration, at least until other factors take over.

Also, more esoterically, the fluid would have to resist any possibility of vaporizing during this event

Posted by Kenny M on 2006-09-30 09:31:49