Difference between Mass and Weight?

Click For Summary

Discussion Overview

The discussion centers around the distinction between mass and weight, exploring definitions and implications in various contexts, including gravitational effects on different celestial bodies and scenarios like free fall.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that mass is a measure of the amount of matter in an object and remains constant regardless of location, while weight is the gravitational force acting on that mass.
  • Others argue that weight can be context-dependent, as illustrated by scenarios such as being in a falling elevator or on the Moon, where weight is perceived differently due to the effects of gravity.
  • A participant highlights that the term "weight" can be used synonymously with mass in everyday language, which may lead to confusion regarding its scientific definition as a force.
  • One participant raises a discrepancy regarding the weight experienced on the Moon, suggesting a different calculation than what was previously stated, indicating uncertainty about the relationship between mass and weight in varying gravitational fields.

Areas of Agreement / Disagreement

Participants express differing views on the definitions and implications of mass and weight, with no consensus reached on certain aspects, particularly regarding weight calculations in different gravitational contexts.

Contextual Notes

Some limitations include the potential confusion arising from colloquial versus scientific definitions of weight, as well as the assumptions made about gravitational forces in various scenarios.

Jadaav
Messages
175
Reaction score
1
What is the difference between Mass and Weight?

Because i often get confused about it.

It's concerned about Newton's second law.

I'm trying to learn it by myself.:)
 
Physics news on Phys.org
Mass is how much stuff there is in an object - it doesn't change.
Weight is the force that the Earth pulls on the mass with.

So on the moon you would have the same mass, but only 1/6 the weight.
In a falling elevator you would be weightless but not massless.
 
mgb_phys said:
Weight is the force that the Earth pulls on the mass with.
In a falling elevator you would be weightless but not massless.
These are two rather distinct definitions of weight. The gravitational force that the Earth exerts on a person in a falling elevator is no different than the force that the Earth exerted on this unfortunate person while he was waiting for the elevator. In this context, weight is just a synonym for gravitational force.

We call the person in the falling elevator "weightless" because that person truly does feel something quite different than the person waiting for the elevator. The same feeling of weightlessness occurs when a skydiver first jumps out of an airplane and when an astronaut is in a quiescent (non-thrusting) orbiting vehicle. That second definition of weight is called apparent or scale weight.

Finally, legally and colloquially, weight is a synonym for mass rather than having units of a force. In this context, a one pound can of peas weighs one pound anywhere on the Earth, in a space station, on the Moon, and in deep space.
 
Thanks for the answers guys:)
 
mgb_phys said:
Weight is the force that the Earth pulls on the mass with.

Some discrepancy here:

So on the moon you would have the same mass, but only 1/6 the weight.

Assuming it is force that Earth pulls me with, when on Moon surface I should weight much less than that, about 1/3640 :-p
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 51 ·
2
Replies
51
Views
6K
  • · Replies 23 ·
Replies
23
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 46 ·
2
Replies
46
Views
5K
  • · Replies 14 ·
Replies
14
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 202 ·
7
Replies
202
Views
15K