# The blood pressure in human is greater at the feet than at the brain. Why?

(a) The blood pressure in human is greater at the feet than at the brain. Why ?
(b) Atmospheric pressure at a height of about 6 km decreases to nearly half its value at the sea level, though the 'height7 of the atmosphere is more than 100 km. Why ?
© Hydrostatic pressure is a scalar quantity even
though pressure is force divided by area, and force is a vector. Why ?

(a) The height of the blood column in the human body is more at the feet than at the brain. That is why, the blood exerts more pressure at the feet than at the brain
(b) We know that the density of air is maximum near
the surface of earth and decreases rapidly with height and at a height of about 6 km, it decreases to nearby half its value at the sea level.‘Beyond 6 km height the density of air decreases very slowly with height. Due to this reason the atmospheric pressure at the height of about 6 km decreases to nearly half of its value at sea level.
© Since, due to applied force on liquid, the pressure
is transmitted equally in all directions inside the liquid. That is why there is no fixed direction for pressure due to liquid. Hence hydrostatic pressure is scalar quantity.
As A > > a, therefore F > > f
This shows that the small force applied on the smaller piston will be appearing as a very large force on the large piston. As a result of which a heavy load placed on the larger piston is easily lifted upwards.