Acork of density $0.5\ gcm^{-3}$ floats on a calm swimming pool. The fraction of the cork’s volume which is under water is …….. $\%$

A air bubble of radius $1\,cm$ in water has an upward acceleration $9.8\, cm\, s ^{-2}$. The density of water is $1\, gm\, cm ^{-3}$ and water offers negligible drag force on the bubble. The mass of the bubble is$…….gm$

$\left( g =980 \,cm / s ^{2}\right)$

A cylindrical block of wood of base area $30\ cm^2$ , floats in a liquid of density $900\ kg/m^3$ . The block is depressed lightly and then released. The time period of the resulting oscillations of the block is equal to that of spring with block of same mass, then spring constant is equal to …….. $N/m$

A vertical triangular plate $ABC$ is placed inside water with side $BC$ parallel to water surface as shown. The force on one surface of plate by water is (density of water is $\rho $ and atmospheric pressure $P_0$ ) 

An ice block floats in a liquid whose density is less than water. A part of block is outside the liquid. When whole of ice has melted, the liquid level will