A wooden cube of side 10 cm has mass 700 g. What part of it remains above the water surface while floating vertically on water surface?

Explanation

Each side of the block = 10 cm
Volume of the cube = `10^3 = 1000 "cm"^3`
Mass of the cube = 700 g
Weight of the block = 700 gf
Volume of the block under water = `V "cm"^3`
Mass of displaced water = V g
Upthrust = V gf
According to law of flotation,
Upthrust = Weight of the block
`therefore V = 700 "cm"^3`
So, volume above water surface =1000 - 700
= `300 "cm"^3`