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Ultimate IQ test for those who are interested..
- Thread starter out_at_sea
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S
Sundance
Guest
There seem to be some controversy about this one
A rowboat is floating in a swimming pool. Which will raise the level of the water in the pool higher?
Dropping a marble in the pool.
Dropping a marble in the rowboat.
Both will raise the water the same.
A rowboat is floating in a swimming pool. Which will raise the level of the water in the pool higher?
Dropping a marble in the pool.
Dropping a marble in the rowboat.
Both will raise the water the same.
S
Sundance
Guest
And this one too:
Roentgen : (X rays : Van Allen Belt)) is to ( Bohr : (Hydrogen : Unnilennium )) as ( Oppenheimer : (theory of relativity : atomic bomb)) is to _____ ?
(Planck : (radiation formula : thermonuclear bomb))
(Feynman : ( nanotechnology : radio telescope))
(Rutherford : (atomic structure : theory of gravity))
(Teller : ( quantum foam : hydrogen bomb))
(Curie : (radiation : neutron bomb))
(Einstein : (E=MC2 : cold fusion))
Roentgen : (X rays : Van Allen Belt)) is to ( Bohr : (Hydrogen : Unnilennium )) as ( Oppenheimer : (theory of relativity : atomic bomb)) is to _____ ?
(Planck : (radiation formula : thermonuclear bomb))
(Feynman : ( nanotechnology : radio telescope))
(Rutherford : (atomic structure : theory of gravity))
(Teller : ( quantum foam : hydrogen bomb))
(Curie : (radiation : neutron bomb))
(Einstein : (E=MC2 : cold fusion))
out_at_sea
Banned
plornive said:
What did you answer to those posted by SUndance ?
When we break most of the questions apart yesterday those 2 questions have different answers..
Imnotdutch
butler monkey
Sundance said:
The third answer is correct. It is related to density. Water has a density of one.......so 1 cm3 has a mass of 1g.
Assume the volume of the marble is 1cm3 (any numbers will work).......the mass will be 1g.
If you drop the marble into the pool it will displace an equal volume of water........1cm3.
Dropping it into the boat involves displacement. The boat displaces a mass of water that is equal to its mass. So if you increase the mass of the boat by 1g (by adding the marble) then 1g of water will be displaced. This is equivalent to increasing the volume of water by 1cm3.
So dropping the marble in each place has exactly the same effect.
plornive
New member
But the region which the water is displaced to is smaller when you throw the marble into the boat, due to the region of space used by the boat and the fact that the boat will not rise with the water (as it would if the marble was thrown into the water).Imnotdutch said:
I'm guessing that if the boat takes up 20% of the surface of the water, the water will rise 25% higher if the marble is thrown into the boat. I don't know how much the boat will sink from the marble because I haven't studied physics for a while... but I imagine it's just enough to displace one marble's worth of mass of water.
Last edited:
Imnotdutch
butler monkey
I'm just rethinking here........been a long day 
A marble is more dense than water because it sinks (I assume it is made of glass or other dense material.....which is normal). Therefore if the marble is put into the pool the mass of water that it displaces will be less than the mass of the marble.
If the marble is put into the rowboat the amount of water that will be displaced will be equal to the mass of the marble. As the marble has a greater mass than an amount of water that is equal to its volume putting the marble into the boat will cause more water to be displaced than putting it directly into the pool.
So the answer is..........B.
That makes more sense now. It all came down to the relative densities of the water and the marble.
A marble is more dense than water because it sinks (I assume it is made of glass or other dense material.....which is normal). Therefore if the marble is put into the pool the mass of water that it displaces will be less than the mass of the marble.
If the marble is put into the rowboat the amount of water that will be displaced will be equal to the mass of the marble. As the marble has a greater mass than an amount of water that is equal to its volume putting the marble into the boat will cause more water to be displaced than putting it directly into the pool.
So the answer is..........B.
That makes more sense now. It all came down to the relative densities of the water and the marble.
plornive said:
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