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Something I will give the metric system all day.
They have different units for torque and pressure. Newton-Metres and Pascals.
In standard they're both foot-pounds.
One place metric fails epically, though is weight.
We tend to think of mass being the same as weight, but it's not.
Its because we don't go where there isn't 1g pulling on us all the time.
1kg is 1kg at 0g, 1g and 10g.
1lb at 1g is 100lb at 10g and 0lb at 0g.
That's because weight is mass at a given acceleration.
But SI doesn't have a weight unit and Imperial doesn't have a real mass unit.
It makes space gaming fun.
Especially when you try to explain how contragravity reducing a ship's weight to zero doesn't reduce its mass to zero and that while, even though it's buoyant in the local atmosphere, it will not shoot up like a rocket because of inertia from its mass.
PS: I know that the Pascal is a unit derived from Nm over an area (1 metre squared).
Even on earth gravity isn't uniform. It's damned close, and for most things the tiny variances don't matter a lot. But sometimes it might matter. For those cases I begrudingly have to give the edge to metric, because you can add the gravity variation (mostly by elevation and/or proximity to the poles I'd guess) to the calculations. Although possibly depending on how weight is measured in Imperal it isn't necessary. I'll have to think about that. Not that it matters that much to me, like I said, the variances are infintesimally small. For a system like GURPS where Pi=3... probably doesn't matter at all.
ReplyDelete-swj
To be kind of pedantic:
ReplyDeleteNewton-meters is Newtons x meters. Pascals is Newtons / (meters ^ 2).
The Imperial unit for pressure is pounds per square inch (psi) and not ft-lb.'
With that said, I work with both and neither is as easy as their proponents claim. I wish we could just stick to one, but it's too late now.
Daosus
PSI is technically correct (the best kind) but...
DeleteBut shall we mention that ft-lb to torque on a wheel is not the same ft-lb measured on a dyno?
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ReplyDeleteFrom a former shop teacher/science teacher who had to get kids to use both systems. The SI unit of weight is the Newton. A kilogram weighs 9.8 Newtons on Earth. The SA (Senseless American) unit of mass is called a slug. A slug weighs 32 lbs on Earth. Fractions of an inch are hell on Jr Hi kids, but so are Kilo, Hecta, Deca, deci, centi, milli.
Newtons are force, not weight. Not quite the same thing.
DeleteGiggleworthy is 1g doesn't come out even in metric. So much for inherently better...
Weight is a measure of the force of gravity on an object. Pounds and newtons both are measures of force. In what ever direction the force is applied and then measured.
DeleteYou're talking about a derived equivalence to weight using mass and force. Mass and force can be used to calculate weight, but the newton is a measure of force, not weight.
DeleteYou're just going to have to accept it because it's how metric is.