Two vessels of equal cross-sectional area $A$ are filled with a liquid of density $d$. The height of the liquid in one vessel is $h_1$ and in the other vessel is $h_2$. When both vessels are connected,find the work done by gravity.

An air bubble of volume $1\,cm^3$ rises from the bottom of a lake $40\,m$ deep to the surface at a temperature of $12^{\circ}C$. The atmospheric pressure is $1 \times 10^5\,Pa$,the density of water is $1000\,kg/m^3$,and $g = 10\,m/s^2$. There is no difference in the temperature of water at the depth of $40\,m$ and on the surface. The volume of the air bubble when it reaches the surface will be $..........\,cm^3$. (in $,cm^3$)

If the heart pushes $1 \ cc$ of blood in one second under pressure $20000 \ N/m^2$,the power of the heart is ....... $W$.

$A$ uniform meter scale is supported at its $20 \ cm$ mark. $A$ body suspended from the $10 \ cm$ mark keeps the scale horizontal. However,the scale becomes unbalanced if the body is completely immersed in water. To regain the balance,the body is shifted to the $8 \ cm$ mark. Therefore,the specific gravity of the material of the body is

$A$ vertical cylindrical container of base area $A$ and an upper cross-section area $A_1$ making an angle $30^{\circ}$ with the horizontal is placed in an open rainy field as shown,near another cylindrical container having the same base area $A$. The ratio of the rates of collection of water in the two containers will be:

What is dynamic lift?