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Another Physics Question

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minnesotamaniac
Posts: 128 - Karma: 415
This might be a bit easy, but lets see what you have to say about it.

You are out on a lake fishing on a cool morning. You finally find a good place to fish so you drop your ancor in the water. The water level
A. Rises
B. Lowers
C. Stays the same
D. Rises then lowers
Jan 17 2006 5:38PM
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oakleyaaa
Posts: 558 - Karma: 23
i'm only in chem so i have no idea, but i would think that the water level might incredibly slightly increase, or i could go out on a limb and say that since its warm out, instead of rising it will take less pressure in the water for the molecules to pack together tighter, resulting in no change in depth............and yes, i have no clue, but i'd like to hear the answser
Jan 17 2006 5:44PM
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Anathema
Posts: 21048 - Karma: 5,061
lowers
Jan 17 2006 5:49PM
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Sknsnw9
Posts: 957 - Karma: 10
i was fooled by a question similar to that...and the water level stays the same!!! thats the answer
Jan 17 2006 5:51PM
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oakleyaaa
Posts: 558 - Karma: 23
^i believe u, but how is that possiblle, we need chronic99 to answer this one
Jan 17 2006 5:52PM
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4-Front
Posts: 5306 - Karma: 199
im gunna have to say "rises" because the anchor takes up space so the water must rise
Jan 17 2006 5:54PM
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Sknsnw9
Posts: 957 - Karma: 10
ok, ill explain why it will stay the same, because you have the anchor in ur boat its the same weight, then you put it in the water still the same. but wait i could be wrong becasue the volume could be different compared to the weight so i might be wrong...
Jan 17 2006 5:56PM
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Itsbackfliptime
Posts: 18901 - Karma: 75
it stays the same because of the weight of the anchor pushing down on the boat is gonna displace the same amount of water wheter or not it is in or out of the boat.

Pretty sure.
Jan 17 2006 5:59PM
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cfveinot
Posts: 180 - Karma: 14
^ you guys are right.
Jan 17 2006 6:08PM
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cfveinot
Posts: 180 - Karma: 14
it's c
Jan 17 2006 6:11PM
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oakleyaaa
Posts: 558 - Karma: 23
haah thats actually wicked cool, physics sounds cool
Jan 17 2006 6:16PM
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Lateralis
Posts: 1228 - Karma: 332
of course it stays the same and honestly, you think a little 10 or 15lb anchor would actually make the water of a lake rise??? naw
Jan 17 2006 6:19PM
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DYFI
Posts: 3836 - Karma: 30
haha thanks. I also believe that the water would stay the same.
Jan 17 2006 6:31PM
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wang_bong
Posts: 766 - Karma: 13
actually, dropping a 15lb anchor in the lake would raise it a little bit. actually a very little bit like .0000001 inches or something. but this would only be if you dropped it in from the shore or from a plane or something. since he is putting it in the lake from the boat, it stays the same.
Jan 17 2006 6:39PM
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CooksCorner
Posts: 3939 - Karma: 22
its intresting but...its boring
Jan 17 2006 7:09PM
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C-Burg
Posts: 4729 - Karma: 130
c the same amount of force is on the water because the anchor was in the boat
Jan 17 2006 7:15PM
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thecoyote
Posts: 1937 - Karma: 14
Actually the water level in the lake will fall. Heres why:
When you have the anchor in your boat, it is pushing the boat downward with a force of Mass x 9.8m/sec. So in the boat, it is now displacing its WEIGHT in water. When the anchor is now resting on the bottom, the boat will rise up out of the water displacing less water. The anchor is in the water, but its weight is resting on the bottom, so now it is only displacing its VOLUME in water. With such a dense heavy object like an anchor, it displaces much more volume by pushing the boat downwards, then it does resting at the bottom.
Jan 17 2006 7:24PM
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thecoyote
Posts: 1937 - Karma: 14
I forgot to mention one of the principles I described.
If you float an ice cube, and it melts, the water level will stay the same. Because ice is less dense then when it melts it should take up a smaller volume. But the ice will float so that a small portion of it is above the water, it only displaces its weight in water. A boat will do the same, displacing its weight in water.
Jan 17 2006 7:26PM
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jonnydub
Posts: 940 - Karma: 10
this guy is right
Jan 17 2006 7:27PM
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iheartskiing7
Posts: 410 - Karma: 10
it rises. the anchor displaces the space that the water had filled and there for making the displaced water rise because it has no where else to go
Jan 17 2006 7:29PM
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MattMcGinnis
Posts: 2396 - Karma: 73
yea man, i think coyote is right, becuase what if you had a huge glass box that was 10'x20'x30', but had a weight of like 20lbs?
Jan 17 2006 7:33PM
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jonnydub
Posts: 940 - Karma: 10
when things float they displace their weight in water.
Jan 17 2006 7:34PM
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P-JO
Posts: 6853 - Karma: 75
Coyote is definitely right...every one else is mildy retarded.
Jan 17 2006 7:36PM
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minnesotamaniac
Posts: 128 - Karma: 415
Congrats, you got it right
Jan 17 2006 7:39PM
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jibjim
Posts: 1814 - Karma: 10
wow, your dumb, it rises because as the water heats up it expands, i might be very wrong here though
Jan 17 2006 7:44PM
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C-Burg
Posts: 4729 - Karma: 130
water expands when it freezes
Jan 17 2006 7:48PM
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jonnydub
Posts: 940 - Karma: 10
yea your wrong
Jan 17 2006 7:48PM
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Chubby.Chaser
Posts: 2926 - Karma: 15
and an anchor does not float, thus proving coyete's theory. The boat anchor combo weighs, say 100lbs, and displaces 100lbs of water, and the water pushes the boat up 100lbs, toss the anchor and the boat weighs 80 pounds now, displaces 80lbs of water. The new total water displaced is 80lbs plus the volume of the anchor, which is less than the previous displacement of of 100lbs (assuming the anchor has a lower volume than 20lbs of water). The less water displaced by objects in the water, boat/anchor, the lower the level of the water.
Jan 17 2006 8:33PM
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JazzyJ
Posts: 3233 - Karma: 18
sometimes itll hit you and you'll be like woah man! but sometimes its just not super interesting.
Jan 17 2006 8:36PM
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cfveinot
Posts: 180 - Karma: 14
wow im dumb as shit, haha, ohh well
Jan 17 2006 8:43PM
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C-Burg
Posts: 4729 - Karma: 130
any time you put something into a liquid it rises, but most of the time it is too small to care
Jan 17 2006 8:45PM
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Jessbuff
Posts: 2685 - Karma: 17
That's right because water has a density of +/- 1g/cm^3, whereas steel has a higher density (7.85g/cm^3).

So on the boat a 20kg anchor would displace 20 cubic meters of water. Whereas in the water it would only displace 2.55 cubic meters of water.
Jan 17 2006 8:50PM
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Chubby.Chaser
Posts: 2926 - Karma: 15
20 cubic metres of water is 20,000 kg dude
Jan 17 2006 8:53PM
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Chubby.Chaser
Posts: 2926 - Karma: 15
Systeme Internationale!
Jan 17 2006 8:54PM
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Jessbuff
Posts: 2685 - Karma: 17
Yea, I think you're right, I definitely messed up the decimal place. FIX IT FOR ME! But either way, the point is that the density of the anchor is greater than the water and that is why it displaces less whe it is in the water than when it is on the boat.
Jan 17 2006 8:57PM
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Anathema
Posts: 21048 - Karma: 5,061
woops, i meant to say rises. because the volume of the boat is greater than the volume of the anchor. sure, the weight it the same, but the displacement of the water is related to volume, not weight.
Jan 17 2006 9:05PM
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C-Burg
Posts: 4729 - Karma: 130
what is the answer
Jan 17 2006 10:15PM
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thecoyote
Posts: 1937 - Karma: 14
YEEESSSSSSSSSSS
Jan 17 2006 11:29PM
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thecoyote
Posts: 1937 - Karma: 14
Although I am an astrophysics major, so it's kinda like cheating
Jan 17 2006 11:29PM
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Anathema
Posts: 21048 - Karma: 5,061
oh shit, maybe i meant lowers.....


but all in all, who cares. the anchor is displacing a couple cubic feet of water out of an entire fucking lake. relatively speaking, that's basically saying the water level is staying the same. volcanic activity, tectonic plates shifting, glaciers melting, surrounding land eroding, precipitation, evaporation. all this shit contributes way greater to the level of water in a lake.
Jan 17 2006 11:32PM
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logange
Posts: 1428 - Karma: 159
i get it with cayote, wen the anchor is in the boat it is pushing the whole boat down which is greater then just allowing it to float
Jan 18 2006 12:09AM
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jambone
Posts: 934 - Karma: 11
stays the same. the anchor displaces the same amount of water in or out of the boat
Jan 18 2006 10:34AM
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Lateralis
Posts: 1228 - Karma: 332
unless a 4 billion tonne asteroid were to slam into a huge lake. only then would we see a significant rise in the water but only for a little bit cuz then there would 400foot killer waves going in each direction eliminating mankind for thousands and thousands of miles
Jan 18 2006 12:17PM
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spo14
Posts: 285 - Karma: 10
yupp
Jan 18 2006 2:08PM
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