about buoyancy

[ICUatUCI]

i am a bit confused on buoyancy concept. I searched through previous threads but didn't really get what i was looking for.

Let say, we have two objects A and B (density water > A > B), then which one has greater buoyancy? I am thinking A because even though both float, A more submerged due to having a greater density than B, meaning it displaces more water. Is this correct?

If that's correct, then what about in air. Because in air, the lighter the substance, it floats more (meaning greater buoyancy). Am I supposed to use different thought process?

Thank you

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[liveoak]

think volume first Force-B is always equal to the volume displaced*density of fluid*gravity.

If your two objects have the same mass, the LIGHTER one will have the greater buyancy (sp??) because it will have more volume, and thus displace more water.

 

[wish2bMD]

I had the same thought process as liveoak; however, Kaplan states that 2 blocks of the same mass (5kg mass -one floats with 60% of its mass above the water, the other 40%) experience the same buoyant force. The reasoning? Since they have equal masses, they both experience the same force of gravity.