Official Fulqrum Publishing forum

Official Fulqrum Publishing forum (http://forum.fulqrumpublishing.com/index.php)
-   Pilot's Lounge (http://forum.fulqrumpublishing.com/forumdisplay.php?f=205)
-   -   archimedes principle debunked, confusing you :) (http://forum.fulqrumpublishing.com/showthread.php?t=26896)

raaaid 10-08-2011 02:25 PM

archimedes principle debunked, confusing you :)
 
you have one meter stick of density 0.9

how does it float on water horizantally or vertically?

yeah horizontally the metacentrum thing

if you put it vertical from where does it get the energy to flotate horizontally if in both cases evacuates same amount of water?

do you realize the only thing they did with you is reinforce your faith and kill your critic spirit by going to college?

i know ive spent the last 20 years there :)

skouras 10-08-2011 02:29 PM

i lost you to the last part:grin:

raaaid 10-08-2011 02:35 PM

why if you put a wood long stick on water it floats horizontal and not vertical if in both cases evacuates same water?

raaaid 10-08-2011 02:54 PM

well the answer and to think like this is what keeps me failing physics :) is this:

with wood the lower its in water the more potential energy it has

the cog of the stick is lower vertically than horizontally and mother nature if it can its generous and spends potential energy

but the thought worth having its that in both cases it evacuates same water so the force should be equal

but the the only equal force is the vertical staright force in both cases

but theres a twist rotational force that only appears with the stick vertical

therefore with the same force of buoyancy according archimedes. The force is actualy stronger in one case than the other

but dont worry i wont tell this my physics teacher as i wont tell my psichiatrist that all tvs are stereovision ;)

edit:

or i could be all wrong because if you put a 0.5 density stick cog will be in same position however it floats but id say it will float horizonatlly

i know ill confuse you cause im confused and im finishing nautic engineering :)

bongodriver 10-08-2011 05:31 PM

center of gravity

AndyJWest 10-08-2011 05:48 PM

Quote:

Originally Posted by bongodriver (Post 346401)
center of gravity

Yup. The centre of gravity of the stick id presumably half way along its length, while the centre of buoyancy is half way along the length of the immersed portion - which puts it below the CoG. This is dynamically unstable., as any slight tilt will tend to increase. If the stick is horizontal, it may roll on its own long axis to reach the most stable position (which will depend on the cross section), but any tilt along its length will be self correcting.

For many real floating objects, the situation is more complex than this - a ship can have multiple 'stable' orientations, and the 'funnel up' one may actually be the least stable. See also http://en.wikipedia.org/wiki/Metacentre#Metacenter.

raaaid 10-08-2011 06:02 PM

yes but think this:

a floating stick of density 0.5 what will happen here:

either center of gravity of the stick and level of water doesnt change wetaher the stick floats horizontal or vertical

then how can go from one position to other if no energy was spent?

bongodriver 10-08-2011 06:24 PM

center of gravity....or your stick must have an equal length/width/depth.....i.e. is a cube shaped stick.......simples

superman 10-08-2011 06:33 PM

more surface tension if it floats horizontally...

AndyJWest 10-08-2011 07:05 PM

Quote:

Originally Posted by raaaid (Post 346422)
yes but think this:

a floating stick of density 0.5 what will happen here:

either center of gravity of the stick and level of water doesnt change wetaher the stick floats horizontal or vertical

then how can go from one position to other if no energy was spent?

My brain hurts! I think I need to draw a diagram...


All times are GMT. The time now is 02:16 PM.

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright © 2007 Fulqrum Publishing. All rights reserved.