Explain the working of a hydraulic brake with a simple labelled diagram.

Pressure is _____ in all directions about a point in a liquid.

(choose from same/different)

Pressure at a point inside a liquid is _____ to its depth.

(Choose from directly proportional/inversely proportional)

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.

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

At sea level, the atmospheric pressure is $76 \text{cm of Hg}$. If air pressure falls by $10 \text{mm of Hg}$ per $120 \text{m}$ of ascent, what is the height (in $\text{m}$) of a hill where the barometer reads $70 \text{cm of Hg}$. State the assumption made by you.