Thrust and Pressure

Why is it essential for deep-sea diving vessels to be built of thick sheets of steel?

The students made four holes in the bottle along a vertical line. They put the bottle in a sink. They used water from a tap to keep the bottle filled to the top. The students measured and recorded the vertical heights of the holes above the sink. They also measured the horizontal distances the water landed away from the bottle. A pair of measurements for one of the holes is shown in the diagram.

The complete data from the experiment is shown in the table.

Which hole is shown in the diagram?

A 'U' tube contains oil, carbon tetrachloride and water as shown in the figure. The density of oil is $0.8 \mathrm{g} {\mathrm{cm}}^{-3}$ and that of carbon tetrachloride is$1.6 \mathrm{g} {\mathrm{cm}}^{-3}$. If oil and water surfaces are at the same level, then the height of the water column is 

Knives are ground to a thin edge to

A body has a face area of $100 {\mathrm{cm}}^2$ and a mass of  $100 \mathrm{N}$ is placed on the table. What pressure is it exerting on the table ?

The pressure applied on the ground is more, when a man is

An elephant weighing $40,000 \mathrm{N}$ stands on one foot of area $1000 {\mathrm{cm}}^2$ whereas a girl weighing $400 \mathrm{N}$ is standing on one 'stiletto' heel of area $1 {\mathrm{cm}}^2$.

What is the ratio of pressure exerted by the girl to the pressure exerted by the elephant?

A metal cuboid of mass $\text{'}\mathrm{M}\text{'} \mathrm{kg}$ rests on a table with surface area of $40 {\mathrm{cm}}^2$ in contact with the table. The pressure exerted by the cuboid on the table surface is $10000 \mathrm{Pa}$. What is the value of $\mathrm{M}$? (Given that $\mathrm{g}=10 \mathrm{m} {\mathrm{s}}^{-2}$).

A student takes a cuboid with dimensions $(l\times b\times h)$ $8 \mathrm{cm}$, $6 \mathrm{cm}$ and $4 \mathrm{cm}$. He measures the pressure $P$ of the cuboid using $(l\times b)$ face. Now he uses another cuboid of the same material with the dimensions double of the previous ones and repeats the experiment. What will be the change in the value of pressure for the new cuboid?

A student places an iron cuboid of dimensions $1 \mathrm{cm}\times 4 \mathrm{cm}\times 10 \mathrm{cm}$ on the loose sand with its side of dimensions (i) $1 \mathrm{cm}\times 4 \mathrm{cm}$ and (ii) $4 \mathrm{cm}\times 10 \mathrm{cm}$ lie on sand. If the pressures exerted by the cuboid in two cases are $P_1$ and $P_2$ respectively, then $\frac{P_1}{P_2}$ must be: