Random tangent, it was about 3 years ago that I realized that 1kg wasn’t exactly 2.2lb (1 lb = 0.4545kg) but actually 2.2046lb (1 lb is about 0.4536kg).
Idk, I’m not very good at remembering people and names but somehow way better with numbers and a mix of oddly specific things. In this instance I was at a bulk store with a close friend.
Also remember it changes based on location. Weight is not a direct correlation to mass. It will vary by altitude.
The easy way to remember it is that 1kg is 1kg at any altitude or location as it is a measure of mass. The same object will weigh a different number of pounds on earth at sea level than high in the atmosphere, on the moon, etc as it is a measure of weight
Actually, while you are correct about weight in general, the pound is legally defined as a unit of mass, which is exactly equal to 0.45359237 kg. Then, multiplying this pound-mass by 1 ft/s^2 gets you a pound-force which is a unit of weight. This implies that the pound-force is a derived unit in US Customary, British Imperial, and the other countries that agreed to the 1959 definition of the avoirdupois pound as a unit of mass.
So while the earth would induce less pounds-force of gravity on an object high in the atmosphere than at sea level, the object would not lose pounds-mass, which is what pounds actually are unless the multiplication by 1 ft/s^2 is specified explicitly or implied. This is the case for any systems that use the avoirdupois pound.
No physicist would use pounds to define mass in the U.S. It is just wrong. Weight sure, but that same 1959 definition you mentioned did not mention it as mass from what I am seeing, rather weight - mass. I’ll see if I can find the actual accord to see if they list the terms used when proposed as it would be foolish to use pounds, next thing you know we would get a moon lander laying on its side. Haha. : )
I couldn’t find the text of the agreement, but here is the notice from the US Department of Commerce based on that agreement. What’s interesting is that they discuss the relation of the 1959 definition to previous ones, and even back in 1893 the pound was standardized as a unit of mass.
So it seems like, for at least 130 years, we have been “using the pound wrong” and no one bothered to correct us.
Haha, So that would require us to use pound and pound to have to different meanings. 1 pound of mass not equal to 1 pound of weight unless you are in the right circumstances haha. How dumb. Thanks for sending me that link by the way!
my understanding is not so much altitude as the density of what’s pulling you, as in the ground below you. like if your at the top of a granite mountain it may have more pull than if you’re on the ocean. if you search for gravity anomaly maps you can see what I’m getting at. of course the farther you are from something the less pull it has though so I get your altitude point but unless you’re in a hot air balloon weighing rice I don’t know how altitude would matter. not that there is a big enough difference for weight vs mass to ever matter with rice.
Random tangent, it was about 3 years ago that I realized that 1kg wasn’t exactly 2.2lb (1 lb = 0.4545kg) but actually 2.2046lb (1 lb is about 0.4536kg).
Why do you remember the day?
Idk, I’m not very good at remembering people and names but somehow way better with numbers and a mix of oddly specific things. In this instance I was at a bulk store with a close friend.
Also remember it changes based on location. Weight is not a direct correlation to mass. It will vary by altitude. The easy way to remember it is that 1kg is 1kg at any altitude or location as it is a measure of mass. The same object will weigh a different number of pounds on earth at sea level than high in the atmosphere, on the moon, etc as it is a measure of weight
Actually, while you are correct about weight in general, the pound is legally defined as a unit of mass, which is exactly equal to 0.45359237 kg. Then, multiplying this pound-mass by 1 ft/s^2 gets you a pound-force which is a unit of weight. This implies that the pound-force is a derived unit in US Customary, British Imperial, and the other countries that agreed to the 1959 definition of the avoirdupois pound as a unit of mass.
So while the earth would induce less pounds-force of gravity on an object high in the atmosphere than at sea level, the object would not lose pounds-mass, which is what pounds actually are unless the multiplication by 1 ft/s^2 is specified explicitly or implied. This is the case for any systems that use the avoirdupois pound.
No physicist would use pounds to define mass in the U.S. It is just wrong. Weight sure, but that same 1959 definition you mentioned did not mention it as mass from what I am seeing, rather weight - mass. I’ll see if I can find the actual accord to see if they list the terms used when proposed as it would be foolish to use pounds, next thing you know we would get a moon lander laying on its side. Haha. : )
I couldn’t find the text of the agreement, but here is the notice from the US Department of Commerce based on that agreement. What’s interesting is that they discuss the relation of the 1959 definition to previous ones, and even back in 1893 the pound was standardized as a unit of mass.
So it seems like, for at least 130 years, we have been “using the pound wrong” and no one bothered to correct us.
Haha, So that would require us to use pound and pound to have to different meanings. 1 pound of mass not equal to 1 pound of weight unless you are in the right circumstances haha. How dumb. Thanks for sending me that link by the way!
Weight is just the measurement of gravity on mass.
Mass is absolute AFAIK
my understanding is not so much altitude as the density of what’s pulling you, as in the ground below you. like if your at the top of a granite mountain it may have more pull than if you’re on the ocean. if you search for gravity anomaly maps you can see what I’m getting at. of course the farther you are from something the less pull it has though so I get your altitude point but unless you’re in a hot air balloon weighing rice I don’t know how altitude would matter. not that there is a big enough difference for weight vs mass to ever matter with rice.