Acontainer of large surface area is filled with liquid of density $\rho$ .Acubical block of side edge $a$ and mass $M$ is floating in it with four-fifth of its volume submerged. If a coin of mass $m$ is placed gently on the top surface of the block is just submerged. $M$ is
$4\ m/5$
$m/5$
$4\ m$
$5\ m$
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 large ship can float but a steel needle sinks because of
A block of volume $V$ and of density $\sigma _b$ is placed in liquid of density $\sigma _l(\sigma _l > \sigma _b)$ , then block is moved upward upto a height $h$ and it is still in liquid. The increase in gravitational potential energy of the system is
A small solid ball is dropped from a height above the free surface of a liquid. It strikes the surface of the liquid at $t = 0$. The density of the material of the ball is $500\ kg/m^3$ and that of liquid is $1000\ kg/m^3$ If the ball comes momeritariiy at rest at $t = 2\ sec$ then initial height of the ball from surface of liquid was ..... $m$ (neglect viscosity)
Water is pumped from a depth of $10 $ $m$ and delivered through a pipe of cross section $10^{-2}$ $m^2$. If it is needed to deliver a volume of $10^{-1} $ $m^3$ per second the power required will be ........ $kW$