# Please help me to solve Q 3

Dear Student,

Volume of the wooden cube

= 10 x 10 x 10 = 1000 cm^{3}

When the cubic block floats, the volume of water displaced by the submerged part

= 10 x 10 x (10-3)

= 700 cm^{3}

Mass of this water

= V x d

= 700 x 1 => 700 g

As the cubic block is floating,

Weight of the displaced water = Weight of the block

Hence, density of the block = Mass /Volume

= 700/ 1000

= 0.7 g/cm-3

So, density of water = 1 g/cm^{3}

So, Part of cube submerged in water,

= density of body/density of water

= 0.7/1

= 7/10

Part of the cube above water = 1 - 7/10

= 3/10

Hence, 3 cm of cube is above the water.

Regards

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