Plz explain the term dynamic mass ? And how can mass of a body change with vel.?
110591
The term is probably refering to the appearent increase in mass as an object's velocity increased toward to the speed of light.  At ordinary speeds, this effect is negligible, but when the object's speed is a significant percentage of the speed of light, it becomes important.\n\nIn reality, mass of the object stays the same, it is the momentum that increases.  As an object approaches the speed of light, it momentum increases.  An object would have an infinite momentum at the speed of light.  With an infitite momentum, it would require an infinite amount of energy to accelerate something to the speed of light, meaning that is impossible.
1163903
Set m1 = 0.145 kg, v1i = 0.720 m/s\nand m2 = 0.295 kg, v2i = 2.22 m/s\n\nConservation of linear momentum:\nm1v1i + m2v2i = m1v1f  + m2v2f\nSimplified\nm1(v1i-v1f) = -m2(v2i-v2f)\n\nConservation of energy (kinetic only):\n(1/2)m1v1i^2 + (1/2)m2v2i^2 = (1/2)m1v1f^2 + (1/2)m2v2f^2\nSimplified:\nm1(v1i - v1f)(v1i + v1f) = -m2(v2i - v2f)(v2i + v2f) \n\nSolving the two simplified equations:\nv1f =((m1-m2)/(m1+m2))v1i + ((2m2)/(m1+m2))v2i\nand\nv2f =((m2-m1)/(m1+m2))v2i + ((2m1)/(m1+m2))v1i\n\nTherefore,\nv1f = 3.315 m/s\nv2f = 1.23 m/s
247359
Mass interacting with gravity
48083
If the mass of the earth changes, then if we could "weigh" it on a scale, its weight would change. Changing the mass of the earth definitely affects its rotation rate, and its orbit, as well as all the other orbits of bodies in the solar system, including the sun, and of course, bodies outside the solar system. \n\nAll of the laws of motion and gravity that the earth and the other bodies obey depend on the mass of the earth.\n\nHow might mass of the earth change?\n \n1. The earth is gaining mass every year from meteorites of course. The amount of material falling to earth is estimated to be between 37,000 and 78,000 tons per year (see first reference).\n\nI am not sure if this includes material from the solar wind, or from the tails of comets, or from cosmic dust (see below) which are also sources of material from space that the earth gathers, but I believe it does. \n\n\n2. The earth is also losing material because we are now launching satellites and sending space vehicles off on missions. \n\n3. At the boundary of the atmosphere and space (the exosphere) where air can escape into space. The amount of air that is lost depends on how fast the ions, atoms and molecules in the upper atmosphere are moving. I have including a web page that discusses this below. \n\n4. When radioactive material decays, it can emit electromagnetic radiation (gamma rays) that carry off a tiny amount of mass. Some of these gamma rays might make it all the way out of earth's atmosphere, but very few I would imagine. I am not sure how to estimate this. It would definitely have to be balanced against the flood of radiation that the earth is being bathed in by the sun and by cosmic rays. \n\nWithout doing any calculations, I would guess that the earth is probably experiencing a net gain of mass every year, and this increases the force of gravity between it and all the other celestial bodies. It also will make it spin more slowly, as the moment of inertia of the earth changes. However, the gain is very small. From the figures above, the earth's mass increases by roughly 10^(-15) per cent per year; that is, the earth experiences a gain of about 0.000000000000001 %  per year.
1124621
Easy question. You mass increases as your velocity approaches the speed of light. And if you have a graph of mass as a function of velocity ( mass on the y-axis and velocity on the x-axis) you will notice a vertical assymtote where v =c. \n\nThe actual equation is this: m(v) = (m_rest)/(1-(v/c)^2) \n\nyour m(v) is your actual mass. your m_rest is your mass at rest, your mass when there is no relative velocity. and your v is velocity and c is the speed of light ( 3 E 8 m/s)...hm... there may bee a square root in there somewhere. I think there may be a square root over the denominator. anyways, doesnt matter look at this:\n\nSo if.. v = c then you end up with m_rst/0 which equals infinity!\n\nAlso there are 2 other factors. if your veolicy is simply your distance over time x/t right? Well according to the lorenz transformation equations. as your veolicty increasis, your distance gets small and your time dialates which makes that fraction way smaller. So... you put more and more and more energy into something and you get less and less and less speed out of it.
441441
Be careful not to confuse the concept of weight with the concept of mass. The Earth's weight would depend on the acceleration due to gravity (Here on Earth we call it 'little g' and it's 9.8 m/s squared) on the enormous planet with a huge bathroom scale that you could set the whole planet Earth on. The Earth's mass doesn't change (except for increasing steadily due to cosmic dust accumulation) when you move it from gravitational field to gravitational field.  Likewise your weight changes when you walk on the moon, but your mass stays the same. It's the different acceleration due to gravity  (The moon's instead of the Earth's) that changes your weight.
820356
mass = the amount of matter, independant of gravity and in sci units measure in kg's\n\nweight= force, the downward pull on an object due to gravity, measure in N (newtons)
313524
Mass is a property of some physical object that specifies the amount of matter and energy it contains. Be careful and don't confuse mass with weight -- an astronaut in orbit has no weight but his/her mass remains the same.
1061816
Hai Shaumik\nBy Einsteins energy mass relation E=mC^2 , but mass is inversely proportional to velocity\nA body with small mass have high velocity compared to a body having greater mass. This implies that a body having zero mass moves fast. There is no such object having zero mass. so no body can move with greater or equal to velocity of light
964876
Mass is the property of an object to resist movement when a force is applied against it.  While it is often measured as weight and the space it occupies as volume; the mass of an object is constant and independent of these two measurements.  Mass is considered the force exerted on an object and that force the object exerts on the universe.  (The Galilean equivalence principle states these two forces are equal, due to our limited understanding of gravity.)\n\nIn a gravitational field the mass is acted upon by the force of gravity (and there is no place in the known universe where the force of gravity doesn't apply).  The mass can be measured by its weight, but the weight changes as the gravity field changes an the mass does not.  The volume of the object can vary independent of the gravity field, but it is not a measurement of mass since it varies with the temperature.  The mass also describes the power due to gravity that the object exerts on other objects.  Until we understand gravity better then the power of gravity imparted to an object by its mass equals that of the gravitational power imparted to other objects by that object.\n\nIn Einstein’s theory of Special Relativity and particle or quantum physics the mass of an object is the same in all frames of reference.\n\nAccording to Wikipedia:  http://en.wikipedia.org/wiki/Mass\n"Mass is a property of a physical object that quantifies the amount of matter and energy it is equivalent to. Mass is a central concept of classical mechanics and related subjects, and there are several forms of mass within the framework of relativistic kinematics (see mass in special relativity and mass in General Relativity). In the theory of relativity, the quantity invariant mass, which in concept is close to the classical idea of mass, does not vary between single observers in different reference frames.\n\nIn classical mechanics, there are three types of mass or properties called mass:\n\n-  Inertial mass is a measure of an object's resistance to changing its state of motion when a force is applied. An object with small inertial mass changes its motion more readily, and an object with large inertial mass does so less readily. \n-  Passive gravitational mass is a measure of the strength of an object's interaction with the gravitational field. Within the same gravitational field, an object with a smaller passive gravitational mass experiences a smaller force than an object with a larger passive gravitational mass. (This force is called the weight of the object. In informal usage, the word "weight" is often used synonymously with "mass", because the strength of the gravitational field is roughly constant everywhere on the surface of the Earth. In physics, the two terms are distinct: an object will have a larger weight if it is placed in a stronger gravitational field, but its passive gravitational mass remains unchanged.) \n-  Active gravitational mass is a measure of the strength of the gravitational field due to a particular object. For example, the gravitational field that one experiences on the Moon is weaker than that of the Earth because the Moon has less active gravitational mass.\n\nAlthough inertial mass, passive gravitational mass and active gravitational mass are conceptually distinct, no experiment has ever unambiguously demonstrated any difference between them. This empirical observation leads to the equivalence principle of general relativity. The weak form of the equivalence principle states that this correspondence between inertial and gravitational masses is not accidental, and that no experiment will ever detect a difference between them."\n\nAccording to Wikipedia:  http://en.wikipedia.org/wiki/Invariant_mass\n"The invariant mass or intrinsic mass or proper mass or rest mass or just mass is a measurement or calculation of the mass of an object that is the same for all frames of reference. For any frame of reference, the invariant m
393015
If a body is fixed at its center of gravity, it is in a state of neutral equilibrium.\n\nTherefore, the whole weight of the body can be assumed to act at the center of gravity.\n\nThe following method is used to find an expression for the C.G of a solid body.\n\nThe solid body is considered to be broken up into elementary particles.\n\nIf m1, m2, m3 etc are the masses of the particles, their weights are m1g,m2g, m3g etc.\n\nThe weights are acting parallel to each other in the downward direction.\n\nIf we assume that the C.G is at the point X,  and x1,x2,x3 etc are the distances of m1,m2,m3, then the  sum of MOMENTS of all these weights about the origin must be equal to the moment of the whole weight of the body about its C.G.\n\nTherefore,   Mg .X =  ( m1g .x1 + m2g .x2+ m3g .x3 + m4g .x4+ ....) where M = sum of all masses.\n\nIn short, the moments of weights of small particles in a solid body about any point is equal to the moment of the whole weight of the body about its C.G.
906577
Hi!\n(A) \nBy definition di=dm * X^2 , where di is the amount added to I when the mass dm is added to the system. I~Inertia . In this case for the particle X=d.\n\nEach mass m=0.85 kg add to the system (delta I)1 = m * d^2.\n\nEach rod has an Inertia of (delta I)2 = (1/3) M * d^2 . This is because for a rod you have to calculate:\n             S { dm * x^2 = (M/d)*dx * x^2 } ==> (M/d) * (1/3)(X^3) with X=d. => (1/3)M * d^2  \n\nso the total inertia of the system is I= 2*[ m*d^2+ (1/3) M*d^2] because we have 2 rods and tho particles.:\n    I= 7.84 * 10^(-3) kg / m^2.    Where ^ is used for power!\n\n(B) kinetic energy= (1/2) Inertia  * (angularspeed)^2 =3.528 /10^4\n\nIf you want to know more try the link below!
89835
In terms of mass.\nThe SI unit for mass is the kilogram (kg).\n\nDo not confuse mass with weight, they are not the same thing.  The mass of an object is constant throughout the universe where as weight is a vector force that depends on the gravitational field around the object.  It is unfortunate that these two words are used interchangably sometimes.
1132748
Mass does two things:\ni) it provides resistance to accelerations\nii) it couples to gravitational fields\n - note that according to the equivalence principle of general relativity these two things could actually be the same thing.\n\nTo measure mass you measure one of those two effects.  For example you strongly accelerate a small particle (eg by strong magnetic field) and measure the velocity it reaches in a given time.  This measures its resistance to acceleration, hence its mass.  Or you measure how it moves in a known gravitational field and infer its mass from that.\n\n\nHope this helps!\nThe Chicken
515258
There are 2 kinds of mass:\n\nGRAVITATIONAL MASS:  The mass you can calculate from Newton's Law of Gravity:  F = G*m1*m2/r^2\nhere m1 and m2 are the gravitational masses of two objects.\n\nINERTIAL MASS:  The mass one can calculate from Newton's 2nd Law of mechanics:  F = m*a\nhere m is the inertial mass of an object.\n\nThey are equivalent (according to Einstein's General Relativity), but it doesn't mean that having one means having the other.  So photons (light) have gravitational mass, but not inertial mass, and so they can travel at the speed of light and at the same time be affected by gravity.\n\nHope I helped.
611971
Mass is a constant; weight varies by gravitational pull.
15257
Weight is defined as the force of attration b/w the earth and the object.\nAs we know that the force is defined as:\nF=m*a    (Force = mass * acceleration)\n\nIn our case, this force is the wieght of the body and the acceleration is the acceleration due to gracity i.e g. So the formula becomes:\n\nw = m*g