## k_lynn one year ago Can someone explain Archimedes' Principle? My book keeps talking about buoyancy and I'm not understanding it.

1. k_lynn

2. k_lynn

The part I'm really messed up on is this "The buoyant force exerted by a liquid is exactly equal to the weight of the liquid displaced." I'm unsure what displaced means.

it is like how mass of water displaced = mass of stuff placed into water except this one results in being able to make an inference to the density of the object... I think... I didn't do so well in my physics class tho

5. k_lynn

ok. It makes a little bit more sense. I get that you put something in water and mass is lost. I just am really confused because I'm not sure what displaced means in that sense.

like if you had a graduated cylinder, it would be how much the water rises

7. k_lynn

ohh. So I put a brick in a bath tub or something and measure the amount of water I put in before I put the brick in. Then once I do put the brick in I measure how much is in there now and subtract? That would be the amount of mass lost?

more equations than that .-.

9. k_lynn

in a general sense would that be right?

the actions yes but you wouldn't magically get the mass lost by subtracting

if you have a graduated cylinder half filled with water you make note of the mass/volume of water/height in relation to the cylinder you take note of the original mass of a marble convert that mass into Newtons you put the marble into the cylinder with the water make note of the increase in height calculate the volume of water that increased convert that to Newtons that would be the new Newtons of your marble subtract Original Newtons by new Newtons of the marble to find the lost mass

12. k_lynn

Ok. My book is going over this for specific gravity. And in order to find specific gravity, you have this formula- $S.G=\frac{ mass~of~object }{mass~of~water~displaced~by~the~object }$ Right? If I know the mass of water displaced by the object, I can find Specific Gravity?

not the right formula? http://study.com/cimages/multimages/16/specificgravityformula1.png

ohhh nvm I see what you're saying but it still should be (weight of object) / (weight of displaced fluid) note: weight and mass are different things

15. k_lynn

okie. I think I get this now. Thanks so much for helping me!