A boy has $60\, kg$ weight. He wants to swim in a river with the help of a wooden log. If relative density of wood is $0.6$, what is the minimum volume of wooden log? (density of river water is $1000\, kg/m^3$)
$0.66\, m^3$
$150\, m^3$
$\frac{3}{1}m^3$
$\frac{3}{20}m^3$
What is the direction of buoyant force ?
A block of ice floats in an oil in a vessel when the ice melts, the level of oil will ..............
A ball of relative density $0.8$ falls into water from a height of $2$ $m$. The depth to which the ball will sink is ........ $ m$ (neglect viscous forces) :
A rectangular box has water in it. It is being pulled to the right with an acceleration $a$. Which of the following options shows the correct shape of water surface on it ?
In Guericke's experiment to show the effect of atmospheric pressure, two copper hemispheres were tightly fitted to each other to form a hollow sphere and the air from the sphere was pumped out to create vacuum inside. If the radius of each hemisphere is $R$ and the atmospheric pressure is $p$, then the minimum force required (when the two hemispheres are pulled apart by the same force) to separate the hemispheres is