Explain
why
(a) The
blood pressure in humans is greater at the feet than at the brain
(b)
Atmospheric pressure at a height of about 6 km decreases to nearly
half of its value at the sea level, though the height of the
atmosphere is more than 100 km
(c) Hydrostatic
pressure is a scalar quantity even though pressure is force divided
by area.
Explain why
(a) The blood pressure in humans is greater at the feet than at the brain
(b) Atmospheric pressure at a height of about 6 km decreases to nearly half of its value at the sea level, though the height of the atmosphere is more than 100 km
(c) Hydrostatic pressure is a scalar quantity even though pressure is force divided by area.
(a) The pressure
of a liquid is given by the relation:
P
= hρg
Where,
P
= Pressure
h
= Height of the liquid column
ρ
= Density of the liquid
g =
Acceleration due to the gravity
It
can be inferred that pressure is directly proportional to height.
Hence, the blood pressure in human vessels depends on the height of
the blood column in the body. The height of the blood column is more
at the feet than it is at the brain. Hence, the blood pressure at the
feet is more than it is at the brain.
(b) Density of air is the maximum near the sea level. Density
of air decreases with increase in height from the surface. At a
height of about 6 km, density decreases to nearly half of its value
at the sea level. Atmospheric pressure is proportional to density.
Hence, at a height of 6 km from the surface, it decreases to nearly
half of its value at the sea level.
(c) When force is applied on a liquid, the pressure in the
liquid is transmitted in all directions. Hence, hydrostatic pressure
does not have a fixed direction and it is a scalar physical quantity.
(a) The pressure of a liquid is given by the relation:
P = hρg
Where,
P = Pressure
h = Height of the liquid column
ρ = Density of the liquid
g = Acceleration due to the gravity
It can be inferred that pressure is directly proportional to height. Hence, the blood pressure in human vessels depends on the height of the blood column in the body. The height of the blood column is more at the feet than it is at the brain. Hence, the blood pressure at the feet is more than it is at the brain.
(b) Density of air is the maximum near the sea level. Density of air decreases with increase in height from the surface. At a height of about 6 km, density decreases to nearly half of its value at the sea level. Atmospheric pressure is proportional to density. Hence, at a height of 6 km from the surface, it decreases to nearly half of its value at the sea level.
(c) When force is applied on a liquid, the pressure in the liquid is transmitted in all directions. Hence, hydrostatic pressure does not have a fixed direction and it is a scalar physical quantity.
