Rubber weights vs. Iron weights

[IronKop77]

So is a Kg of feathers the same weight as Kg of iron??




















JK bros as stated above a Kg=a Kg.
The only thing I could figure out is possibly a bounce for deadlifts or something of that nature.

 

[Dr. M]

So is a Kg of feathers the same weight as Kg of iron??

In a vacuum, yes. But in air, buoyancy due to the greater air displacement of a kg of feathers makes it actually weigh less. Both have the same MASS, but the weight of the feathers is less due to Fgravity-Fbuoyancy.

Just a little mind-fucking for you

-M

 

[drrman]

In a vacuum, yes. But in air, buoyancy due to the greater air displacement of a kg of feathers makes it actually weigh less. Both have the same MASS, but the weight of the feathers is less due to Fgravity-Fbuoyancy.

Just a little mind-fucking for you

-M

actually wrong, you can't weigh a "mass" a mass is a universal constant. 1 lb of feathers is the same as 1 lb of lead. But, then you are going to say drop each at the same time and see which hits the bottom first, then you start getting into computational fluid dynamics and drag over surface areas, but lifting weights, there is no drag. believe me, i have a masters in mechanical engineering

 

[Sigmund Roid]

I have actually measured the weight of rubber and metal plates on an accurate scale. In our gym the rubber ones are heavier than the metal ones. The difference is caused by pounds - kilo conversion. Our metal plates are European and are 20 kilos (gauged for competition). The rubber ones are from the US, and they are 45 pounds. However, 45 pounds is more than 20 kilos.
1 pound = 0.45359 kg, so 45 pounds is 20.41 kg, so they are heavier than our 20 kilo plates.
0.41 kg does not seem much, but if you have 8 plates on your bar, that is an extra 3.28 kilos.
Besides the US ones are not gauged, and they have additional weight besides the lbs-kg conversion. This can add up to an extra 5% increase in weight.