Can Velocity Alone Determine an Object's Mass?

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Discussion Overview

The discussion centers around the question of whether an object's mass can be determined solely from its velocity, without considering other factors such as force, density, or momentum. Participants explore this concept through hypothetical scenarios and reference established physical laws.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question the feasibility of determining mass based solely on velocity, suggesting that different objects can have the same speed regardless of their mass.
  • A participant presents a hypothetical scenario involving an object moving towards Earth, prompting others to challenge the assumption that velocity alone can indicate mass.
  • There is mention of gravitational effects, with participants noting that all objects are influenced by gravity equally, and their trajectories do not depend on mass.
  • Some participants reference Kepler's Third Law and the independence of gravitational acceleration from the mass of the object being accelerated.
  • Another participant asks how the scenario relates to Newton's Laws of motion, indicating a desire to connect the discussion to established principles of physics.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether mass can be determined from velocity alone. Multiple competing views are presented, with some arguing against the possibility and others exploring the implications of the question.

Contextual Notes

The discussion includes hypothetical scenarios that may lack sufficient context or assumptions necessary for a complete analysis. The relationship between mass, velocity, and gravitational effects remains unresolved.

John Clement Husain
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Is it possible to find the mass without force/density/momentum but with velocity only?
 
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John Clement Husain said:
Is it possible to find the mass without force/density/momentum but with velocity only?

You mean, for example, if something is moving at ##1m/s## then it must have a mass of ##7.4kg##?
 
something like this:
An object, with a distance of 1300 km, in space is moving in 100 km in 10 s towards Earth, find it's mass.
 
John Clement Husain said:
something like this:
An object, with a distance of 1300 km, in space is moving in 100 km in 10 s towards Earth, find it's mass.

Why would that determine its mass? Why couldn't a small object (a rock) and a large object (an asteroid) be moving at the same speed?

In particular, all objects are affected by gravity to the same extent. Their trajectories or orbits do not depend on their mass.

You could, however, estimate the mass of the Earth from looking at the orbits of things moving around it or things falling towards it.
 
nope
 
PeroK said:
Why would that determine its mass? Why couldn't a small object (a rock) and a large object (an asteroid) be moving at the same speed?

In particular, all objects are affected by gravity to the same extent. Their trajectories or orbits do not depend on their mass.

You could, however, estimate the mass of the Earth from looking at the orbits of things moving around it or things falling towards it.
you mean Kepler's Third law?
 
John Clement Husain said:
you mean Kepler's Third law?

More fundamentally the acceleration of gravity is independent of the accelerated mass.
 
John Clement Husain said:
something like this:
An object, with a distance of 1300 km, in space is moving in 100 km in 10 s towards Earth, find it's mass.
How would that tie in with Newton's Laws of motion?
 

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