TBR Chem: Fluid/Solids

[LuminousTruth]

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Three objects with the same density but different sizes are placed in a tank of water as shown below. (In terms of volume, object 3>object2>object1.) After the objects are released:

A) Object 1 has greatest acceleration
B) Object 2 has greatest acceleration
C) Object 3 has greatest acceleration
D) All three objects will have the same acceleration

I know this question is not supposed to be that hard, but I am having trouble understanding how the correct answer was "D".

Since buoyant force, B=p(fluid)*V(displaced fluid)*g, the three objects displace different volumes of fluid. B-mg=ma => a=(B-mg)/m. How could the acceleration be the same?

 

[peacefulheart]

use B-mg=ma => a=(B-mg)/m and rho*g*V, V(volume ) cancels out.