Is 'lb per ft' a Unit of Force or Work? Confirm & Explain Here

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Discussion Overview

The discussion revolves around the interpretation of the unit 'lb per ft' and whether it should be classified as a unit of force or work. Participants explore its application in engineering contexts, particularly in statics, and reference a popular culture example for clarification.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant states that 'lb per ft' is used as a unit of force in engineering courses, specifically for calculating moments.
  • Another participant argues that 'lb per ft' represents a distributed load, which is a force per unit length, distinguishing it from work, which is measured in ft-lb.
  • A participant expresses confusion about the reference to 'lb per ft' as a unit of work, seeking clarification on the reasoning behind this claim.
  • Some participants clarify that the unit of work in the English system is 'lb-ft', not 'lb per ft'.
  • There is a suggestion that the misunderstanding may stem from a mishearing of the term 'ft-lb' as 'lb per ft'.
  • One participant notes the relationship between work, force, and distance, indicating that work is calculated as force multiplied by distance.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the classification of 'lb per ft'. There are competing views regarding its interpretation as a unit of force versus a unit of work, and the discussion remains unresolved.

Contextual Notes

The discussion highlights potential confusion arising from terminology and the need for clarity in distinguishing between units of force, distributed loads, and work. There are unresolved assumptions about the context in which 'lb per ft' is used.

dangish
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So in this engineering course I do at my university called Statics, we often use a unit of lb per ft as a unit of force when calculating moments.

However, I was just watching an episode of Big Bang Theory when Sheldon said something about a common mistake being when people use lb per ft as a unit of force and that it's rather a unit of work.

Can anyone confirm this and explain the reasoning behind it?
 
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You're both wrong.

The unit lb per ft is for a distributed load. It's a force per unit length, not simply a force.

Work is a force multiplied by a displacement, so its units are ft-lb, not lb/ft.
 
ya I didnt mean lb/ft i meant to multiply them

so why would he say it was a unit of work, there must be some reason
 
I agree with vela - the unit of work in the English system is lb-ft. Could it be that you misheard the speaker?
 
dangish said:
so why would he say it was a unit of work, there must be some reason
What is the "it" you are referring to? ft-lb?
 
Nope its in the season finale of season 1, the only connection I can make is that work = force*distance which could also be a ft*lb
 
yes the it was referring to a ft-lb
 
Im not agreeing nor disagreeing with either of you, I was just curious as to what the guy on the show meant haha
 
dangish said:
Nope its in the season finale of season 1, the only connection I can make is that work = force*distance which could also be a ft*lb
That's pretty much it.
 

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