Factors that affect
pressure:
i) Force: Pressure is
directly proportional to the applied force.
ii) Area: Pressure is
inversely proportional to the area on which force is applied.
Some reasonable facts:
i) All the cutting and piercing tools such
as scissors, needles, knives, etc. have
sharp edges.
Ans: We know that
pressure is inversely proportional to the area of application of
force. If the cutting and
piercing tools such as scissors, needles, knives, etc. have sharp edges, the
force applied through smaller areas produces greater pressure
and hence they can easily
cut or pierce something.
ii) Football shoes have
studs on them.
Ans: We know that
pressure is inversely proportional to the area of application of
force. Studs on the
football shoes help to decrease the area of the base of the shoes. The weight
of footballers exerted through the smaller area produces greater
pressure due to which
footballer does not slip on the ground.
Define 1 Pascal pressure.
Ans: Pressure produced by
the application of 1 N force on an area of 1 m2 is called 1 Pascal.
What are the factors
that affect liquid pressure?
Ans: i) Depth of the liquid
from its free surface: P ⍺ h
ii) Density of liquid: P ⍺ d
iii) Acceleration due to
gravity: P ⍺ g
Deep sea-divers wear
special diving suits. Why?
Ans: We know that liquid
pressure increases with depth from its free surface. So, in order to withstand the enormous pressure exerted by water
due to an increase in depth, the deep sea-divers wear special diving suits.
It is easier to pull
a bucket of water from the well until it is inside the water but difficult when it comes out of water. Why?
Ans: Upthrust given by
water is more than that given by the air as water is denser than air. Due to this, it is easier to pull a bucket of
water until it is inside the water.
Why does an egg float
on the salt solution but it sinks in pure water?
Ans: The weight of an egg is greater than the
upthrust given by pure water on it. So, the
egg sinks in pure water.
But the density of the salt solution is more than pure water and gives more
upthrust which is equal to the weight of the egg. So, the egg floats in
saltwater.
An iron nail sinks in
water but a ship made of the same material floats in it. Why?
Ans: According to the law of floatation, a body must displace liquid equal to its weight in order to float in the liquid. An iron nail sinks in water because it can't displace water equal to its weight. But the ship is so designed that it displaces water equal to its weight. So, the ship floats in water
Applications of the law of floatation:
i) Floatation of iron
ship
ii) floatation of
hydrometer
iii) floatation of
iceberg
iv) floatation of
submarine
v) Rising of balloons.
हजुरलाई यो सामग्री मन पर्यो भने यसको पूरा पाठ हेर्न यहाँ Click गर्नुहोस् :
हामीले कक्षा ९ गणित विषयको पाठको सम्पूर्ण सामग्री राखेका छौं । हजुरहरूले हेरेर आफुले अभ्यास गर्न सक्नुहुन्छ । यस विषयको पूरा पाठ Sikne Thalo मोबाइल Application बाट निशुल्क हेर्न सकिन्छ ।यसको Size मात्र 4.8MB हो । Download Here
Post a Comment
आफ्नो प्रतिक्रिया सभ्य भाषामा लेख्नुहोस् :