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## Homework Statement

8. When a block of wood with a weight of 30 N is completely submerged under water the buoyant force on the block

of wood from the water is 50 N. When the block is released it ﬂoats at the surface. What fraction of the block will

then be visible above the surface of the water when the block is ﬂoating?

(A) 1/15

(B) 1/5

(C) 1/3

(D) 2/5

(E) 3/5

## Homework Equations

F_app = F_g - F_b

For floating objects:

F_b = F_g

## The Attempt at a Solution

So, to start off, we plug into the first equation to find the apparent weight underwater:

F_app = 30 - 50

F_app = - 20N

I can intuitively see why the answer is 2/5, but can't find the physics of it.