Will a door float if you open it??

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EBunting

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I know how many bears of bigger brain are out there, so can anyone help me with the answer to a niggling physical/existential question. Will a door still float if you open it?

The full explanation of this conundrum is on my Yachting World blog Most grateful if you can help solve the riddle. If you email me at elaine@elainebunting.com I'll post the comments.

Thanks
Elaine
 
Hmmm - if he is sitting on it he couldn't open it upward! If he is sitting on it then it's floating and it won't "open" downward anyway!

Ian, bear with small brain!
 
opening the door would make no difference, unless the door was in the bottom of a boat shaped frame with no positive buoyancy.
 
Elaine

perhaps it might be prudent to modify your email so that it doesn't get picked up by spambots. /forums/images/graemlins/grin.gif

e.g.

fredATblogDOTcom
 
The door sinks - but not you...

The door will immediate orient itself so that it opens downwards, away from you. And because there is no door frame - it will immediately open the moment you sit on it. Arg! BUT... the curvature of the earth combine with the fact that the earth spins at around 1000mph means that you are always on the outside of that door, just as with any other revolving door.
 
Assuming you mean just a door (in or out of a frame) the yes, it will still float, assuming at was floating in the first place. The door is clearly internally boyant, as there is no other structure associated with it causing it to float. Therefor, whatever its orientation, its boyancy remains constant. It may float in a different way, but it will still float.
 
Re: The door sinks - but not you...

Elaine's Door Conundrum is missing one key piece of data.

The apparent speed of rotation of our planet is dependent upon the latitude of the door.

Until we know this datum, all hypotheses are supererogatory.

So there ! /forums/images/graemlins/grin.gif
 
Right...

According to Archimedes for the door and occupant to float the weight of water displaced must be more than equal to the weight of the door and occupant.

Now I assume to be able to open the door, it must be in some sort of frame (otherwise you would be lifting it, not opening it). So the occupant stands on the frame and lifts the door towards them self. The door is now displacing less water and will sink up to the point where equilibrium reurns. However the frame with the occupant will have sunk substantially at the same time.

Am I taking this too seriously?
 
Check out the old Yachting World controversy about whether a supertanker or a yacht causes more water loss from the Panama canal during transit.
 
...... and if it's ajar there will be a draft. Providing the draft isn't too deep you should clear the sandbanks and get away into open sea without any difficulty.
 
Is the door flat or panelled?

If panelled it may have air trapped in the recesses around the water-facing-side panels increasing its bouyancy. Opening the door would allow the trapped air to escape, potentially reducing the bouyancy of the door sufficiently for it to sink.

Hmmm. All my doors at home are panelled. But as home is 300M above the nearest watercourse I am also above the flood plain. Phew!
 
Surely the point of the story was to provoke a stupid debate like this ????

The concept of opening a floating door is ridiculous. The concept of there being anything behind a floating door (apart from water) is ridiculous.

OK, I have fallen for the bait also /forums/images/graemlins/laugh.gif
 
A door is only a concept, a device or an ideology to provide an occasional barrier between 2 or more voids, imaginations, realities or dimensions!
 
Well if you accept (as many people do) that an airplane is kept aloft by the collective willpower of the passengers,then the door ,as a lifesaving concept,is a sure thing.

However,deciding to open it ,like jumping out of a perfectly good plane,may result in a sinking feeling.

Rest assured that whatever happens,the door will continue to support itself (unless it came from B+Q) .
 
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