Mass and force are two very important concepts discussed under mechanics. These are two of the most fundamental physical quantities and are intuitive concepts. It is vital to have a proper understanding in these concepts and the units used to measure them in order to excel in fields like physics, engineering, motor mechanics and many more. To understand what LBM is, one must understand the concept of mass first.
Mass is divided into three different types as inertial mass, active gravitational mass and passive gravitational mass. Experimental data show that all three of these quantities are the same. Matter and energy are two forms of mass.
The common misconception is that the weight is measured in kilograms but, in fact, the weight is measured in Newton. The weight is the amount of force acting on the mass. The kinetic energy of a body, the momentum of a body and the amount of acceleration due to a force applied are dependent on the mass of the body.
For most practical cases, a pound mass and a pound weight define the same amount of stuff on the surface of the earth. There seems to be some confusion here. In the English or American system the "official" measure of mass is the slug.
Turns out that And, as someone said, at "standard" gravity 1 lbm exerts 1 lbf on its support its weight. If you are going to do any significant calculations, it's best, in my opinion, to get rid of all lbm designations and convert everything to slugs.
The force required to accelerate 1 lbm In this case, it is in units of slugs. Know the base units of the unit system you are working in for ANY final solution to be applied appropriately. Both forms are correct! Essentially, 1 , 2 and 3 are all dividing by Know the base units of your system, lbf will always be an ambiguity problem as long as it exists in its current symbolic form. I'd suggest adopting sdl for 2 lbf with unit slug , the ambiguity of pound is an unusual punishment lb, lbs, lbm, lbf, lbf Absolutely, yes you can.
In fact, the mass of a slug is derived from the acceleration due to gravity. I know it is the standard unit for mass and so is lbm. Once you understand this concept well you can go on to familiarize yourself to using slugs. Looking at the last two points above, it is obvious that the newton is very different that the lbf. In the SI system. When you weigh sometime you are measuring a force, yet in SI we record this force in terms of mass kg. Why we can not create a system that make sense is beyond me.
The confusion comes from the English system, we should not ask what is your weight, but what is your mass. Of course this is ridiculous. The confusion comes from an overgeneralization, i. Personally, I think the guy who came up with the pound mass lbm was dyslexic.
What I think he really wanted to do was state that;. This means that lbm is not really a mass unit, but a mass gravitational constant unit which is ridiculous so when you multiply lbm by an acceleration you have to divide out the gravitational constant before you can obtain a force.
Other than by mistake why would anyone come up with such a unit???? Here's how I like to think of it. This is what, for example, your bathroom scale is measuring. Sign up to join this community. The best answers are voted up and rise to the top.
Thus, let us start comparing and differentiating these two units to clear away any confusion. First, let us look at lb or pound.
A pound is a unit measurement of weight used in systems of measurement. Therefore, if you are talking about or have heard a pound, or 1 lb, then it is just equivalent to 0. This is necessary to differentiate and compare the units used in different parts of the world.
An lbf, or a pound force, is the gravitational force exerted by a matter on the surface of the Earth. Thus, it is the force exerted by the mass of one avoirdupois pound.
Thus, 1 lbf, or one pound force, can be measured or converted in Newtons. A pound force is equivalent to the product of 1 pound or 1 lbm one avoirdupois pound and the gravitational field, gn.
In figures it looks like this, 1 lbm x We just multiplied the avoirdupois pound to the standard gravity in metric measurement. This is worth taking note of because a measurement of mass on Earth is not necessarily the same in measurement when in space. Basically, when we talk about lb pound and lbf pound force , we are talking about the same apple. A pound can be stated as a pound force, too, informally, because it measures the same force, which is the force exerted by the mass of a matter on the surface of the Earth.
This is where the line gets really blurry and confusing. We have to really understand the difference and definition of it because a pound in the sea is not a pound on Earth.
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