slug and inertia

Not the slug in question

A little background information will may make this post funny for you…

The system of measurement that we in the US use is sometimes called Imperial units (Imperial as in British Empire), but it goes down hill from there. As an example of this,  US ounces are not and have never been the same as the Canadian (Imperial) ounce.  The fluid measurement system then goes on to make cups (8 ounces), pints (16 ounces, but 20 in an Imperial pints), gallons (128 ounces, or 160 in an Imperial gallons).  It’s all commonplace to us locals, but maybe, just maybe this helps explain our national distrust of numbers (apparently mortgage rate resets are particularly vexing).   Hmm.. maybe we could work out a system in which all units are related by multiples of 10, there are no multiple versions of measurements (ounce, pint, gallon, bushel, barrel, acre-foot, acre-foot ??). How about that metric system.

So, on to the slug. As the metric system has the kilogram as its unit of mass, we have the pound. Oops. Pounds are units of weight.

What is our unit of mass?  Yes, you guessed it. The slug.  Yes, and this is what makes high school physics so exciting. Knowing that your buddy has a mass of 5 slugs.

So here are the factoids:

1 Slug on earth gravity weighs 32.2 Pounds.

1 Kilogram on earth gravity weights 9.81 Newtons.

Why does the US have so much inertia when it comes to changing to the logical metric system ?  I don’t know, but physical inertia derives from mass, and our mass unit is a slug.



NASA criticised for sticking to imperial units