What does 100 tons of concrete weight
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Weighs 100 tons. It might be bouyant or even float but that does not change the weight. Right? What do I win?
"Weight" is a relative thing - the closer the object gets to the center (core) of the earth, the more it weighs. Now, "mass" is something different....
Reading between the lines here; the "weight" of the concrete would be 100 tons minus the weight of water displaced by the concrete. This varies but concrete (only - no rebar) density is ~150 lb/cubic foot; water is ~ 62 lb/cubic foot. This makes the concrete "weigh" about 60% submerged making the total "weight" about 60 tons underwater.
A good demonstration as to why concrete makes poor ballast for sailboats.
A good demonstration as to why concrete makes poor ballast for sailboats.
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The generally accepted submerged weight of concrete is for moorings is:
Concrete = required weight /.55 (example 1000 lbs./.55 = 1818 lbs.)
For example if your harbor master required a 1000 pound dead weight mooring you would need a block of concrete weighing 1818 pounds to have the actual submerged weight be 1000 pounds.
Granite is /.64
Extrapolate out the submerged weight, buoyancy, of 100 tons and you'll have your answer or very close to it..
Concrete = required weight /.55 (example 1000 lbs./.55 = 1818 lbs.)
For example if your harbor master required a 1000 pound dead weight mooring you would need a block of concrete weighing 1818 pounds to have the actual submerged weight be 1000 pounds.
Granite is /.64
Extrapolate out the submerged weight, buoyancy, of 100 tons and you'll have your answer or very close to it..
In the context of the Gulf oil spill, the done system is made up of a 125-ton, 14’ x 24’ x 40’ structure. not 100 tons. The weight figures are indicative of only one thing - the weight on it's skids at the dock. There is no spec for an underwater dome weight so it matters very little what it's underwater weight is.
There are far too many components on the dome made of various materials from lead, copper, steel, aluminum, plastic, glass, etc. to practically identify it's underwater weight but I guess these academic exercises are interesting regardless.
There are far too many components on the dome made of various materials from lead, copper, steel, aluminum, plastic, glass, etc. to practically identify it's underwater weight but I guess these academic exercises are interesting regardless.
http://hyperphysics.phy-astr.gsu.edu/hbase/mass.html
mass times acceleration of gravity . For greater precision you have to consider some other factors. http://encyclopedia.stateuniversity.com/pages/496/acceleration-due-gravity.html
mass times acceleration of gravity . For greater precision you have to consider some other factors. http://encyclopedia.stateuniversity.com/pages/496/acceleration-due-gravity.html
By definition, weight is a force, a vector (directional force), that results from the action of gravity on matter (w=mg). It does not matter where the object is (except when gravity changes significantly with altitude); it will weigh the same. However, when you measure the weight of the object in water or other fluid/gas, you have to account for bouyancy - a quantity acting opposite to gravity and bouyancy will reduce the weight vector acting on the measurement device.
Zero
The weight of a 100 ton concrete boat floating in water is zero until you pull it out of the water and put it on a scale. If the 100 tons is not in the shape of a boat then it could weigh more than zero.
Another example is what is the weight of a hot air balloon floating in air?
The next question will be "why does it float?"
The weight of a 100 ton concrete boat floating in water is zero until you pull it out of the water and put it on a scale. If the 100 tons is not in the shape of a boat then it could weigh more than zero.
Another example is what is the weight of a hot air balloon floating in air?
The next question will be "why does it float?"
Weight is not eliminated by bouyancy. That is like saying a house weighs nothing because it is held up by the soil!!!! If you think that a boat weighs nothing in water get between the boat and a hard place.
It would weigh less. but the mass would remain the same. weight is a vector(having magnitude and direction) force. Mass is not a vector or a force at all, it just IS.
In your example the soil pushes up equal to what the house is pushing down. If one pushed harder than the other, the house would move.
Your boat weighs exactly the same weight if it is floating or on land. The mass is always being accelerated by gravity. The only difference is that in the water the water is opposing gravity and on land the land is opposing gravity. If it is on a travel lift the straps are opposing gravity. Of course the apparent weight is different in water or when the boat is in a travel lift. http://en.allexperts.com/q/Physics-1358/Buoyancy-Weight-Loss-1.htm
Sorry have to disagree
Water is not opposing gravity nor is the soil. Both of these things with mass are also being accelerated by graviy. . Tis is a simple case of F=ma...if you don't belive me go to Westminster Abbey and ask Isaac Newton.
What we are arguing about is the uncertainty principle. The act of measuring it changes the result so we are uncertain. If you put a scale on the bottom of the ocean and rested the block on it you would have the force pushing down on the scale as f=ma with a being relative to distance from the center of earth's mass. This force is the reduced by the force pushing up on the mass by the buoyancy of water. So the measured weight would be less than the weight out of water.
Water is not opposing gravity nor is the soil. Both of these things with mass are also being accelerated by graviy. . Tis is a simple case of F=ma...if you don't belive me go to Westminster Abbey and ask Isaac Newton.
What we are arguing about is the uncertainty principle. The act of measuring it changes the result so we are uncertain. If you put a scale on the bottom of the ocean and rested the block on it you would have the force pushing down on the scale as f=ma with a being relative to distance from the center of earth's mass. This force is the reduced by the force pushing up on the mass by the buoyancy of water. So the measured weight would be less than the weight out of water.
Compression
Concrete is really good in compression. Since the water is acting in all directions the block is trying to be compressed. In fact if you could measure it you would find the volume to be a bit smaller. This in turn will reduce the buoyant force and make the block weigh more as measured on the ocean floor by a fish scale.
Concrete is really good in compression. Since the water is acting in all directions the block is trying to be compressed. In fact if you could measure it you would find the volume to be a bit smaller. This in turn will reduce the buoyant force and make the block weigh more as measured on the ocean floor by a fish scale.
Jibes why don't things just sink to the center of the earth if something is not opposing gravity???
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