A wooden cube floating in water supports a mass 0.2 kg on its top. When the mass is removed the cube rises by 2cm. What is the side legnth of the cube ? Density of water `= 10^3 kg//m^3`

Answer

10 cm

Explanation

Decrease in weight = decrease in upthrust
`:. Mg = V rho_w g`
or `m = V rho_w`
or `0.2 = (2xx10^(-2)Axx10^3)`
where A is the area of the base of cube. Then, `A = 10^(-2) m^2 = 100 cm^2`
Side of the cube, `L = sqrtA = sqrt(100) = 10 cm`