A cube of wood supporting 200gm mass just floats in water. When the mass is removed, the cube ruses by 2cm. What is the size of the cube?

Explanation

The cube just floats means that it is fully under water while floating.

let `m` be the mas of the cube. Then
`(m+200)g=l^(3)rhog` ……..i
When the mas is removed.
`mg=(l-2l)^(2)rhog` …….ii
Substracting eqn ii from eqn i we have
`200=rho[l^(3)-(l-2)l^(2)]`
`impliesl=10cm` (using `rho=lg/cc` of water)