Skip to main content

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...
Post a Comment

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.

  1. Solid
  2. Liquid 
  3. 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 does not flow.

Gas : Matters which have indefinite shape and volume are called gases. For example - air, oxygen, hydrogen etc.

Properties of gas

  • It has indefinite shape
  • It has no fixed volume.
  • It gets the shape and volume of container.
  • It fills the container completely.
  • It has very low density. Because of low density gas are light.
  • It can flow easily and hence are called fluid.

Cause of different physical states of matters

The physical states of matter depend upon three main factors :

  1. The force of attraction between particles.
  2. The space between the particles.
  3. The kinetic energy of particles.

Solid :

  1. The force of attraction between the particles of solids is very strong.
  2. There are minimum spaces between the particles of solids.
  3. The particles of solids have minimum kinetic energy.

Liquid :

  1. The force of attraction between particles of solid is strong but less strong than solids.
  2. The space between particles is more than that of solid but not too more.
  3. The kinetic energy of particles is greater than solid.

Gas :

  1. The force of attraction between particles of gas is almost negligible.
  2. The space between particles of solid is greatest.
  3. The particles of gases have greatest kinetic energy.

Other states of matter

  1. Plasma 
  2. Bose-Einstein Condensate(BEC)


Plasma : It is considered as the fourth state of matter. it is similar to the gas. Particles of plasma are made of free electrons and ions. 

Characteristic of Plasma 

  1. It does not have a definite shape.
  2. It does not have definite volume unless enclosed in a container.
  3. It may be defined as an electrically neutral medium of positive and negative particles.

Notes : 

  • Plasma is one of the most commonly occurring states of matter in universe. 
  • Plasma occurs naturally in the stars. 
  • All stars are made of plasma. Because of the presence of plasma stars glow. 
  • Plasma is formed because of nuclear fusion in stars. Our sun glows because of presence of plasma.
  • Plasma is a super hot and super excited atom. 

Bose-Einstein Condensate (BEC) : It may be considered as fifth state of matter. Satyendra Nath Bose and Albert Einstein were predicted about this state of matters, that’s why it got its name as Bose-Einstein Condensate (BEC).

Characteristic of Bose-Einstein Condensate 

  • Condensate has super cool and super unexcited atoms.

Notes :

  • BEC has been obtained by cooling the vapor of rubidium-87 at super low temperature by Eric Cornell and Carl Wieman on June 5 1995. 
  • After sometimes Wolfgang Ketterle also obtained BEC from sodium-23 at MIT, USA. 
  • Cornell, Wieman and Ketterle got Nobel Prize in Physics for this achievement in 2001.


 

Labels:

Comments

Post a Comment

Popular posts from this blog

Newton’s laws

  Born in 1643 in Woolsthorpe, England, Sir Isaac Newton began developing his theories on light, calculus and celestial mechanics while on break from Cambridge University. Years of research culminated with the 1687 publication of “Principia,” a landmark work that established the universal laws of motion and gravity. Force :  The push or pull on an object with mass causes it to change its velocity. Force is an external agent capable of changing a body's state of rest or motion. It has a magnitude and a direction. (or Push or Pull on an object is called Force.) Newton’s first law: the law of inertia Newton’s first law states that if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force. The law of inertia was first formulated by Galileo Galilei for horizontal motion on Earth and was later generalized by René Descartes. Although the principle of iner...
1 comment
Read more

What is the properties of metal?

  On the basis of their chemical and physical properties of metals are defined as elements that possess properties such as, malleability, ductility, sonorous, l ustre, conductivity and mechanical strength. They show the following properties. Malleable : Metals can be hammered into thin sheets. Ductile : They can be drawn into wires.  Lustre : They have a shiny appearance. Sonorous :  When we strike them, they make a ringing sound.  Conductivity : Metals are a good conductor of heat and electricity. Mechanical Strength : It is the capacity or ability to withstand various loads without deformation or breaking.      
1 comment
Read more

What is metal?

Metals are opaque, lustrous elements that are good conductors of heat and electricity. Most metals are malleable and ductile and are, in general, denser than the other elemental substances. or  Metal is a substance which is lustrous, sonorous, ductile, and is a good conductor of heat and electricity. or Metals are materials holding or possessing the characteristics of being shiny, hard, fusible, malleable, ductile, etc. Few examples of metals (materials) are – Gold, Silver, Aluminium, Copper, Iron, etc. or Metals are materials that are hard, lustrous, malleable, ductile, sonorous and good conductors of heat and electricity. Examples of metals are iron, copper, aluminium, calcium, magnesium, etc
Post a Comment
Read more