Is Our Weight Measured in lbm or lbf? (2024)

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In summary, the conversation discusses the confusion between weight and mass when it comes to measuring one's weight. While domestic scales measure the force applied and display the result in Newtons, they are calibrated in kilograms and assume use on Earth. The concept of weight can vary depending on position and there is a difference between weight and mass. Ultimately, it is important to consider the context of a statement when discussing the measurement of weight.

  • #1

txdw16

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I'm sure this has been asked before but it's annoying me. When we weigh ourselves is it in lbm or lbf?

Because we weigh different on say, the moon, our weight must be lbf right? But if I weigh 150 any unit converter will say I weigh 68kg. Or do I weigh 2.13kg? Can I say I weigh 21 Newtons?
[tex]\frac{150lbf}{32ft/s^2}*\frac{1lbm}{2.2kg}\cong2.13kg*9.8m/s^2\cong21N[/tex]

  • #2

CWatters

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Domestic scales measure the force you apply to them so it would be reasonable for them to display the result in Newtons but they all assume they will be used on Earth and have scales calibrated in kg (or some imperial equivalent). In effect they attempt to display your mass. Since gravity isn't the same everywhere on Earth they won't display the correct mass everywhere.

  • #3

sophiecentaur

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This is an old chestnut. Essentially, Weight is the force which pulls you down and it can vary with position. One really has to come to terms with the common usage of the term 'Weight' and use the context of any statement to decide what is really meant. You can waste far too much time trying to reconcile the two worlds of Science and everyday life. There is a danger of getting a name for nerdiness if you inflict strict definitions on innocent people in civvy street.

  • #4

Khashishi

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Weight is measured in pound-force. Mass is measured in pounds, (or pound mass?). But the term "weigh" can mean many things in the English language, including general measurement. Example: "weigh a decision"

FAQ: Is Our Weight Measured in lbm or lbf?

1. What is the difference between lbm and lbf?

Lbm stands for pounds mass and refers to the amount of matter an object contains. Lbf stands for pounds force and refers to the amount of force an object exerts under the influence of gravity. In simpler terms, lbm is a measure of mass while lbf is a measure of weight.

2. Does it matter which unit I use to weigh myself?

Yes, it does matter which unit you use. If you are measuring your weight on Earth, using pounds force (lbf) is more accurate as it takes into account the force of gravity. However, if you are measuring your weight in outer space or on a different planet, using pounds mass (lbm) would be more accurate as gravity may be different in those environments.

3. Can I convert between lbm and lbf?

Yes, you can convert between lbm and lbf. The conversion factor is 1 lbf = 0.45359237 lbm. So, to convert from lbm to lbf, you would multiply the weight in lbm by 0.45359237. And to convert from lbf to lbm, you would divide the weight in lbf by 0.45359237.

4. Why do some scales measure in lbm while others measure in lbf?

Some scales are designed to measure weight in pounds force (lbf) as it is the more commonly used unit for everyday measurements on Earth. However, some scales may also allow you to switch to measuring in pounds mass (lbm) for more accurate measurements in certain situations.

5. Is there a recommended unit to use for weighing ourselves?

There is no recommended unit to use for weighing ourselves as it depends on the purpose and context of the measurement. If you are measuring weight for everyday purposes, using pounds force (lbf) would be more practical. However, if you are conducting scientific experiments or measurements, using pounds mass (lbm) would be more accurate.

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