A boat carrying steel balls is floating on the surface of water in a tank. If the balls are thrown into the tank one by one, how will it affect the level of water

A block of steel of size $ 5 cm × 5 cm × 5 cm $ is weighed in water. If the relative density of steel is $7,$  its apparent weight is

A $0.5\ kg$ mass of lead is submerged in a container filled to the brim with water and a block of wood floats on top. The lead mass is slowly lifted from the container by a thin wire and as it emerges into air the level of the water in the container drops a bit. The lead mass is now placed on the block of wood. As the lead is placed on the wood.

A boat having a length of $3\,metre$ and breadth $2\,metre$ is floating on a lake. The boat sinks by one cm when a man gets on it. Mass of the man is ....... $kg$

A fluid container is containing a liquid of density $\rho $ is accelerating upward with acceleration a along the inclined place of inclination $\alpha$  as shown. Then the angle of inclination $ \theta $ of free surface is :

A hollow spherical shell at outer radius $R$ floats just submerged under the water surface. The inner radius of the shell is $r$. If the specific gravity of the shell material is $\frac{27}{8}$ $w.r.t.$ water, the value of $r$ is$......R$