Examples of the 
Physics in our Life !

The base of the dam is thicker than its top ?
To overcome the high pressure at great depth since P a h

The nose may bleed at big heights ?
Because the atmospheric pressure decreases by increasing the height from the earth and since the body maintains normal atmosphere , the pressure outside the body becomes less than inside it .

Nails, Pins and knives have pointed or sharp edges?
To decrease the area in contact in order to increase the pressure since P a 1/A

In manometer Mercury in preferred in case of high pressure difference ?
To form reasonable height of liquid column due to its high density

Water preferred in case of low pressure difference ?
to form remarkable height.

Hydraulic press multiplies force ?
Because input force is multiplied by the ratio between the areas of the large and small pistons which is called mechanical advantage .

Liquid inside Hydraulic press must be contain no air bubbles ?
so that the work done by small piston is used to move the large piston instead of compressing bubbles .

The weight of a solid body while it's immersed in a liquid is less than that in air ?
Due to the vertical upward buoyant force which is exerted by the liquid on the immersed part of the solid

An iron nail sinks in water, while a ship made of iron floats on it ?
Because the ship contains a hollow cavity so that the volume of the immersed part is large accordingly buoyant force becomes large enough to keep the ship floating

 liquid drops are having spherical shapes ?
Due to the contracting ST forces which tend to minimize the surface area since spherical shape i sregular having the smallest area for a given volume .

Speed of blood in capillaries is small ?
Due to large total area of capillaries where V1A1=V2A2N "N" the number of capillaries. This makes blood exchange gas and supplies food .