No, it means the object's inertial mass (resistance to acceleration) in the object's own rest frame at any given moment. Unlike with relativistic mass, all observers agree on an object's rest mass.Tregg Smith said:I take it rest mass means relative to the observer.
The concept of mass from different observers refers to the idea that the mass of an object can appear different to different observers depending on their relative motion.
The theory of relativity explains mass from different observers by stating that mass is a relative quantity and can vary based on the relative motion between the observer and the object.
Yes, mass can be measured differently by different observers due to the theory of relativity. An object's mass can appear greater or smaller to different observers depending on their relative motion.
Yes, the concept of mass from different observers has practical applications in fields such as particle physics, where the mass of particles can be measured differently by different observers.
Yes, the principle of equivalence in general relativity also plays a role in understanding mass from different observers. It states that the gravitational mass and inertial mass of an object are equivalent, meaning that an object's mass affects how it moves in a gravitational field.