Concept of mass, momentum and energy

 Mass - The total amount of matters which constitutes a body is termed as the mass of the body. 

        If we discuss about the sub-atomic particles, particles, atoms or molecules, elementary particles etc., such smallest particles built up any substance or body which found in the nature. Such smallest sub-particles have their own characteristics which can account the physical properties like mass, density, volume, energy, etc. For example- if we take an elementary particle, like the electron or proton has its own mass, electrical property, its orientation etc., constitutes any substance with the neutron particle. We also can observed that such elementary particles (like electrons, protons, and neutrons) which took a major role to build a substance made up by other tiny charged quark particles after sub-divided them in the different experiments. So, we concluded that the term 'mass' is the net sum of all particles which contain to the whole body. 

        From the beginning of evolution of 'big bang theory' of our universe, from a highly condensed tiny mass object had been exploded and dispersed and again started to accumulate in numerous binds, and we believe to birth this Universe. That means that everything found this Universe made up by a certain amount of matter, and also total energy of this Universe is constant, e.i., energy can transformed from one form to the other, but it can neither destroy nor create. From this discussion about the matter related with the energy, we may say that mass is equivalent to energy, it might be in any form of energy, viz., mechanical energy, electrical energy, sound energy, light energy, heat energy, muscular energy, molecular vibration energy, etc. This mass-energy relation is given by the Einstein mass- energy relation, E=mc^2, where c is the speed of light in the vacuum.         

Kinetic energy of a moving body of mass 'm' with a linear velocity 'v' is given by 

T = mv^2/2  ------------ (i) 

Kinetic energy of a Rotating body is also given by 

T = iw^2/2  ---------------- (ii) 

where,  w = angular velocity of the rotational body; 

     Here,    v = rw , s = r0* => ds/dt = r d0*/dt => v = r w,  w = d0*/dt

               0* represent the angle described by the rotational body.

               r is a distance from the axis of rotation.

               m is the mass of the particles.  

              i = mr^2 ( moment of inertia of the rotational body). 

and also, 

       Linear momentum, p = mv        ------------- (iii)

       Angular momentum, L = iw           ----------- (iv)

From the above eqs.(i), (ii), (iii) and (iv) - we may say that the moment of inertia is analog to the mass; where the moment of inertia is the tendency of restriction to rotate a body about its rotational axis, so that the inertia is too closely related with the mass, e.i., the greater mass object has the higher inertia. For example, if we try to push or pull a 500 lt empty water tank, it will be easily done; but if you try to push or pull the fully watered tank, you can't easily displace the fully watered tank. This tell us that the fully watered tank has higher mass  which gives a higher inertia and need a stronger force to push or pull as compare with the empty water tank.  



                                                                                                                       to be continue.......

  

         


Comments

Post a Comment

Popular posts from this blog

Physical World Notes

     Physics                           The word Science  originates from the Latin verb Scientia meaning 'to know'. (In Sanskrit, Vijnan has similar meaning, namely 'knowledge'.) Science is a systematic attempt to understand natural phenomena and use the knowledge to predict, modify and control the phenomena. Science is exploring, experimenting and predicting from what we see around us.         The word Physics comes from a Greek word meaning ' nature '; in Sanskrit - Bhautiki . Physics is the branch of Science which deals with the natural phenomena occurring around us. Physics is a discipline of Natural Science to understand the phenomena where occur with us and around us. There are two principal thrusts in physics, i,e. unification and reduction.       Physicists explore the Universe. Their observations and investigations, based on scientif...
Read more

THOUGHTS OF THIS GENERATION

  It is here by introduced about the present scenario of Indian Culture, how it comes, how we learn, how we behave, how we educate, how we live in this Post-Colonial Society since Independence 75 years ago. We were going in this present day without any consciousness. We usually speaks about self-determination, self-realization, disciplines, etc., here I love to mention one important, by how far should we go to discuss about these things? Do we all underdeveloped people who live in this country? Learning: When observing, we with most people of India do not understand the exact or real meaning of learning. Even in the class room also, many teachers teaches pupils with no real sense of learning. We have studied and spent the whole part of teenage of any individual for Education, but here we may ask ourselves, did we test the real beauty of Education?   What did we learn form that effort? Should we do prefer only to get a private or public sector job? What is the exact physi...
Read more

MECHANICAL PROPERTIES OF SOLIDS

RIGID BODY  A rigid body means a body which its ralative position of the constituent particles does not change when an external force is applied on it. A rigid body generally have a definite shape and size. In case of solid, it can be deformed when a sufficiently large external force is applied on it; i.,e., solid bodies are not perfectly rigid an also in practice, no body is perfectly rigid.  ELASTICITY The property of a body which tends to regain its original size and shape, when the external applied force is removed is known as elasticity.  In a solid, the constituent paricles like atoms or molecules have thier definite ralative positions due to its interatomic or intermolecular forces, that means they are in a stable equilibrium position. When the solid is under the action of an external applied force, the atoms or molecules are displaced from thier equilibrium positions. If the external force or the deforming force is removed, these atoms or molecules start to back t...
Read more