It is an inherent property of a given particle. In general, the rest mass of a particle is denoted by m 0. When the particle is moving with velocity v, with respect to the observer, the mass m of the particle is given by,.
Where c is the speed of light through a vacuum. The rest mass of a photon is zero. Rest mass: Rest mass is the mass of a body as measured when the body is at rest relative to an observer, an inherent property of the body.
Inertial mass: Inertial mass is the mass of a body as determined by the second law of motion from the acceleration of the body when it is subjected to a force that is not due to gravity.
Inertial mass: Inertial mass of a particle increases with the relative velocity of the particle with respect to the observer. The inertial mass of a given system is greater than or equal to its rest mass. Inertial mass: If a given particle is at rest with respect to the observer, the inertial mass is equal to its rest mass. It is the lowest inertial mass of the particle.
But, the mass of a particle reaches infinity as the velocity of the particle relative to the observer reaches the velocity of light. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams?
Learn more. What's the difference between the five masses: inertial mass, gravitational mass, rest mass, invariant mass and relativistic mass? Ask Question. Asked 10 years, 7 months ago. Active 2 years, 8 months ago. Viewed 32k times. What's the difference between the five masses: inertial mass, gravitational mass, rest mass, invariant mass, relativistic mass?
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These facts give a nice hook for testing the equivalence of gravitational and inertial mass. See Williams et al. Add a comment. Active Oldest Votes. Inertial mass: To every particle in nature we can associate a real number with it so that the value of the number gives the measure of inertia the amount of resistance of the particle to accelerate for a definite force applied on it of the particle. Rest mass: This is simply called the mass and is defined as the inertial mass of a particle as measured by an observer, with respect to whom, the particle is at rest.
Improve this answer. Community Bot 1. So how will you define force? You can't derive all physical variables from first principles. You need to choose a subset of them that you use to define the others. If you take time and mass, you can define force and momentum with them, if you take time and momentum, you can define force and mass and so on.
At least in a Newtonian world, but the principle is the same for every field of physics. Finally, this representation also can be used to introduce the idea that the energy of an object is the time-component of 4-dimensional momentum. This 4-momentum, which Wheeler called the momenergy, has momentum in the familiar space directions, and also momentum in the time direction which is the energy.
One would expect we could embrace the idea of multiple models here too, but there is a certain ideological element to the attempted banishment of relativistic mass which sometimes approaches zealotry. Centrifugal force is an illusory force that is seen in a rotating coordinate system. However you will still find plenty of physicists who use the idea routinely, just as they talk about Coriolis forces etc. In the right circumstances the idea is quite useful. We keep that concept, though, because it is so useful.
There is real merit in advocating caution in the use of relativistic mass because it does not port very well into realms such as particle physics or even general relativity. But you should not let anyone tell you that relativistic mass is a bad concept. It is just a concept that is useful in some circumstances, and not in others, just like any other physics concept. Proceed with caution. The first is with reference to gravity… where the fact that mass is a property of a system makes things tricky.
Yet the gravity of two orbiting objects really is different than if they were at rest, and light is affected by and generates gravity. Light speed is a limit not because it is impossible to get to, but because of the essential structure of the universe, it is the universal maximum speed. This and other things follow from the fact that this speed is an absolute for all observers, and the limit is woven into the nature of causality.
Light speed is the universal speed, equal to one second per second. For someone observing themselves, this is just the passage of time. However, if you are moving relative to me, your time is mixed with space for me. The faster you go, the more space is mixed in.
If you want to avoid relativistic mass: If you make the choice to eschew relativistic mass you will avoid the issues above, but add a few new ones. In this respect there are arguments both for and against relativistic mass. Using the idea of relativistic mass stresses the connection between mass and energy concepts, since we treat energy as mass in this way.
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