Ahollow cubical box is 0.30 m on an edge. this box is floating in a lake with one-third of its height beneath the surface. the walls of the box have a negligible thickness. water is poured into the box. what is the depth of the water in the box at the instant the box begins to sink?

Explanation:

Given

length of cubical box

If density of object and density of lake liquid

when it is in equilibrium one-third of its height

Buoyancy force will be equal to weight of cubical box

therefore

When water start Pouring in it then height of liquid at which box started to sink

Let H be that height

cancel out the common terms and divide by density of lake