Two cylindrical vessels fitted with pistons A and B of area of cross section $8 {\mathrm{cm}}^2$ and $320 {\mathrm{cm}}^2$ respectively, are joined at their bottom by a tube and they are completely filled with water. When a mass of $4 \mathrm{kg}$ is placed on the piston A, find the pressure on piston B.

Two cylindrical vessels fitted with pistons A and B of area of cross section $8 {\mathrm{cm}}^2$ and $320 {\mathrm{cm}}^2$ respectively, are joined at their bottom by a tube and, they are completely filled with water. When a mass of $4 \mathrm{kg}$ is placed on the piston A, find the thrust on piston B.

What force is applied on a piston of area of cross-section $2 {\mathrm{cm}}^2$ to obtain a force $150 \mathrm{N}$ on the piston of area of cross-section $12 {\mathrm{cm}}^2$ in a hydraulic machine?

What do you understand by atmospheric pressure?

Write the numerical value of the atmospheric pressure on the surface of the earth in pascal.

What physical quantity is measured in torr? How is it related to the SI unit of the quantity?

Name the physical quantity which is expressed in the unit 'atm'. State its value in pascal.

We do not feel uneasy under the enormous pressure above as well as around us. Give a reason.

Describe an experiment to demonstrate that air exerts pressure.