Another Physics Question

minnesotamaniac

minnesotamaniac

Member
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
 
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
 
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...
 
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.
 
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
 
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.
 
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.
 
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.
 
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
 
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?
 
wow, your dumb, it rises because as the water heats up it expands, i might be very wrong here though
 
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.
 
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.
 
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.
 
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.
 
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.
 
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
 
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
 
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