Archimedes' law- find height of something floating (10 points)?

There must be a equilibrium

so, first you have to search what forces act on your block of wood; that is the earth's gravity, and the buoyant force by the water.

so, lets write that down

G=F_b

G=density(of wood) * (total) Volume of wood* earth gravity

F_b = density(of water) * Volume of the block in the water * earth gravity

volume = Surface* height

So what you get

density_wood*total height*surface*gravity = density_water * height under water * surface* gravity

As you can see, the value of the surface and gravity doesn't matter here

answer: height under water = total height * (density_wood)/(density_water)

= (26) * (715/1000)

= 18.59 cm

so the part above water is

26-18.59=7.41 cm

This is different from your answer, but i don't see a mistake in my solution ;)

This question is difficult to understand for me too