Answer
$\mathrm{a}.$ decreases
$\mathrm{b}.$ III
Work Step by Step
Archimedes' Principle
An object completely immersed in a fluid experiences an upward buoyant force equal in magnitude to the weight of fluid displaced by the object.
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$\mathrm{a}.$
In the "high and dry" position, the ball is not immersed, and the buoyant force acts only on the wood. The submerged volume of wood must displace water with weight equal to the wood+steel.
When inverted, the same amount of water needs to be displaced, but some of the water that needs to be displaced is displaced by the ball, leaving less water to be displaced by the wood. As a result, a smaller volume of wood is immersed than it was before.
$\mathrm{b}.$
I is incorrect.
II is correct as far as mass goes, but the conclusion is incorrect.
III is best.
