This thread is a good example of why so many sensible,intelligent people think they can't understand math and physics. The problem isn't that math, or physics, is difficult. It isn't. What is actually going on is about as basic, and understandable as any subject could be. The problem is that people in the field refuse to explain it in understandable terms.

Latch onto this concept: The principles; the reality; that math was invented to describe, existed exactly as they are for quite a few billion years before there were humans or language. The words mathematicions, and physicists, use to describe what is going on, are just noises made with the mouth, or weird markings on a paper. They have no intrinsic meaning in themselves.

Mass and force really are two separate things. There are times when speaking as if they are the same, or using the same unit titles to describe them, can cause confusion. This is particularly true for astrophysicists. Remember, whether or not we use the same word to describe a certain amount of mass, and or a certain amount of force, is up to us. It is something we just decided to do, or not do.
We seem to get along using the same word for different things, like boat that floats on the water, and gravy boat, that holds gravy; and using different words for pretty much the same thing, like cup and mug; but scientific academecians think if we use the same word for an amount of mass; or weight- that is, mass under the influence of gravity on earth; and the amount of force it takes to support that mass when it is on the earth, that we are going to get hopelessly confused. Because they care deeply about us, they decided to help us out of this confusion by introducing a new set of terms that make no sense to anyone who has not gone to some considerable effort to understand them.

Remember, the people who decided that the word pound, or kilogram, would absolutely not do to describe force, are the same people who consider it important , and worth arguing at length about, whether or not Pluto should be called a planet. Pluto does what it does, and is what it is, with no regard whatsoever to what anyone says about it. Forces, and weights, do what they do with no regard whatsoever to what terms are used to describe them.


Consider this: The word pound was used to describe force for many, many years, and the cars, and airplanes, and a whole lot of other things, designed using the word pound as a unit of force, worked just fine.
When torque readings for tightening bolts were given in foot pounds, a whole lot of people working on their cars without torque wrenches handy, knowing about how much force it took to lift 50 lbs, for instance, and knowing they had a 1 foot wrench, were able to come reasonably close to getting the torque right on bolt that specified 50 ftlbs. This worked just fine for many decades. Now torques are given in newtons, and pounds are no longer a unit of force, and somehow we are supposed to believe that if we use pounds as a unit of force, nothing will work and the engine will come apart.
I still have a torque wrench calibrated in foot pounds, and the engines I build hold together just fine.

In summary: 1kn=the force exerted by 225 pounds at rest, on earth, in a downward direction, and knowing this can give a pretty good idea of how strong something is, which is what we were concerned about in the first place.

If you fall, and after all the math, it in reality turns out that you exert the amount of force that we call 10 kn, then if your anchor will hold exactly 2260 pounds, hanging from it statically, then you are ok. If your anchor will hold only 2240 pounds, hanging from it without movement, then you are in trouble.

Thank you for allowing me to vent. I feel much better now.