A wooden block with a coin placed on its top floats in water as shown in figure. $l$ and $h$ are as shown. After some time the coin falls into the water then
$l$ decrease and $h$ increase
$l$ increase and $h$ decrease
Both $l$ and $h$ increase
Both $l$ and $h$ decrease
Two small drops of mercury, each of radius $R$ coalesce to form a single large drop. The radio of the total surface energies before and after the change is
The velocity of a small ball of mass $M$ and density $d_1,$ when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is $d_2,$ the viscous force acting on the ball will be
The height to which a cylindrical vessel be filled with a homogeneous liquid, to make the average force with which the liquid presses the side of the vessel equal to the force exerted by the liquid on the bottom of the vessel, is equal to
An engine pumps water through a hose pipe. Water passes through the pipe and leaves it with a velocity of $2\, m/s$. The mass per unit length of water in the pipe is $100\, kg/m$. ......... $W$ is the power of the engine .
A cubical block is floating in a liquid with half of its volume immersed in the liquid. When the whole system accelerates upwards with a net acceleration of $g/3$ The fraction of volume immersed in the liquid will be