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What is friction and its types?

‘Friction‘ is a force that resists motion of sliding or rolling of one object moving relative to another. It is a result of the electromagnetic attraction between the charged particles of two touching surfaces.   Types of Friction Static Friction : It is defined as the frictional force that acts between the surfaces when they are at rest with respect to each other. The magnitude of the static force is equal in the opposite direction when a small amount of force is applied. When the force increases, at some point maximum static friction is reached. Rolling friction : It is the force that resists motion when an object rolls on a surface. Technically it’s not friction; its ‘rolling resistance’ since when a body rolls perfectly upon a surface, on paper, there is no sliding friction between that object and surface. Sliding friction : It is the frictional force between two surfaces that are rubbing against each other. It’s a very easy and common concept. It’s hard to find a perfectl...
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What is the Law of Conservation of Energy?

The law of conservation of energy states that energy can neither be created nor be destroyed. Although, it may be transformed from one form to another. If you take all forms of energy into account, the total energy of an isolated system always remains constant. All the forms of energy follow the law of conservation of energy.
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What is momentum?

Momentum of a body is defined as the product of its mass and the velocity.  it has both magnitude and direction. Momentum(P) = mv where, m = mass, v = velocity  
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What is Pressure?

  The amount of force exerted (thrust) on a surface per unit area is defined as ‘Pressure’. It can also be defined as the ratio of the force to the area. Formula and Unit of Pressure Pressure (P) = Thrust/ Area The SI unit is ‘Pascals (Pa)’ 1 Pa = 1 Newton per square m or 1N/m^2 Note : Thrust is the force acting normally on a surface. Its SI unit is Newton (N).  Types of Pressure Atmospheric Pressure Absolute Pressure Differential Pressure Gauge Pressure
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Why is the Earth called Blue Planet?

“The Earth has almost 70% water on its surface due to which it looks blue in color”. or “ More than 71% of the earth is covered with water. Hence, its is known as the blue planet ”. Why Earth looks blue from space? The Earth has extremely hot red heat under its crust and the top outer surface is covered with water. The Earth’s surface has many oceans and seas starting from the Arctic Ocean to the Southern Ocean. These oceans & seas cover almost 70% of Earth’s surface and the remaining 30% is covered with land. It means that almost 70% of Earth’s surface appears blue from outer space & the leftover 30% looks greenish-brownish. This is the reason why Earth looks blue from outer space.  
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Define Acids, Bases and Salts.

Acids, Bases and Salts : A substance that tastes sour in water, turns blue litmus red, and neutralises bases is known as an acid. If a substance’s aqueous solution tastes bitter, turns red litmus blue, or neutralises acids, it’s called a base. Salt is a neutral material that has no effect on litmus in aqueous solution. Arrhenius theory
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What is matter?

Anything which has mass and occupies space is called matter. Or Everything that occupies the space and mass is called the matter. Or A matter is anything that has mass and occupies space. Such as Pen, paper, clips, sand, air, ice, etc. are different forms of matter.  For Example : All living things like plants, animals, human beings can be called matter because they have mass and occupy space.  All non-living things like water, oxygen, hydrogen can also be called matter because they also have mass and occupy space. Note : Every matter is made up of tiny particles. These particles are so tiny that they can't be seen with naked eyes.   States of Matter : There are three states of matter. Solid Liquid  Gas Solid : Matters which have fixed volume and shape are called solids. For example - stone, wood, brick, ice etc. All metals are solid except mercury and gallium. Properties of solids It has fixed volume. It has fixed shape. It has high density. It are heavy. It do...
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What is non-metal?

A non-metal is a material which do not have properties of metals like lustre. They are non malleable, non ductile, non sonorous and bad conductor of heat and electricity. Example- Carbon, Sulphur, Phosphorous. Non-metals are the elements which form negative ions by accepting or gaining electrons. Non-metals usually have 4, 5, 6 or 7 electrons in their outermost shell. Very few elements in the periodic table are non-metals. These are present on the right-hand side in the periodic table. Elements that come under non-metals are sulphur, carbon, all halogens, phosphorus, hydrogen, oxygen, selenium, nitrogen and noble gases. Properties of Non-metals : High ionization energies High electronegativities Poor thermal conductors Poor electrical conductors Brittle solids-not malleable or ductile Little or no metallic luster Gain electrons easily Dull, not metallic-shiny, although they may be colorful Lower melting points and boiling point than the metals  Some special facts : Uses of non-...
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