Which is Better for Mechanics: mg or W (Weight)?

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SUMMARY

The discussion centers on the preference between using "mg" (mass times gravitational acceleration) and "W" (weight) in mechanics problems. Participants unanimously favor "mg" for its clarity and ease in spotting cancellations in equations. They emphasize that while both terms represent the same concept (W = mg), using "mg" helps avoid confusion with the term "work." Additionally, some users adopt notation like F_g or F_{Weight} to further clarify their expressions in educational contexts.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Familiarity with free body diagrams
  • Basic knowledge of gravitational force calculations
  • Concept of mass versus weight in physics
NEXT STEPS
  • Explore the implications of using different notations in physics problems
  • Learn about the derivation and applications of W = mg in various contexts
  • Investigate common misconceptions between mass and weight in educational settings
  • Review best practices for teaching mechanics concepts effectively
USEFUL FOR

Physics students, educators, and anyone involved in teaching or learning mechanics who seeks clarity in the representation of mass and weight in equations.

CGUE
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When working out problems in mechanics by drawing free body diagrams and so on, I personally find it better to write mg rather than W (weight) because I confuse it with work.
 
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I prefer mg as well.

CS
 
Mg definitely, I find it easier to spot cancellations.
 
This seems like an odd question to me because W = mg is a definition of W so I don't see why people would choose one over the other. To me is like asking whether I like A or LW for the area of a square with sides L and W. Since A = LW how can you choose what you prefer?

Good question in fact. What do you prefer in the equation A = LW. Do you prefer A or do you prefer LW?

Pete
 
Ed Aboud said:
Mg definitely, I find it easier to spot cancellations.

Seconded … same reason. :smile:
 
If I'm given weight I use W and if I'm given mass I use mg. It doesn't really matter, they're the same thing.
 
I use both depending on whether I'm given weight, or mass, like Kurdt. On the other hand, I usually substitute in mg for w whenever I can so, I have to vote for mg.
 
I write \vec W, which won't be confused with work.
 
I never use any letter than capital F to stand for a force, so I write:

F_g

Or sometimes

F_{Weight}

to help the students.
 

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