# SI Units on Mechanical PE Exam



## kmill80 (Sep 20, 2008)

The new guidelines on the NCEES site state that USCS or SI units could be on the exam, HVAC excluded. Has anyone heard about the extent of SI unit problems that could be on the exam? It adds a lot of work preparing for both.


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## MechGuy (Sep 22, 2008)

kmill80 said:


> The new guidelines on the NCEES site state that USCS or SI units could be on the exam, HVAC excluded. Has anyone heard about the extent of SI unit problems that could be on the exam? It adds a lot of work preparing for both.



I don't really see why it would take any more work to prepare for SI units. The concepts are the same. Have a unit conversion chart handy and you'll be fine.


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## MEPE2B (Sep 22, 2008)

I always found it easier to work in SI units anyway. There's no gravitational constant to worry about, nor pesky conversion factors for units. If I was studying for the exam this time, I would work most of the practice problems in English units, and do a few of them in SI units, just to stay familiar. If you can work them in English units, then working them in SI units is a piece of cake.


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## Sschell (Sep 22, 2008)

MechGuy said:


> I don't really see why it would take any more work to prepare for SI units. The concepts are the same. Have a unit conversion chart handy and you'll be fine.





MEPE2B said:


> I always found it easier to work in SI units anyway. There's no gravitational constant to worry about, nor pesky conversion factors for units. If I was studying for the exam this time, I would work most of the practice problems in English units, and do a few of them in SI units, just to stay familiar. If you can work them in English units, then working them in SI units is a piece of cake.


yes and yes.

$0.02


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## Brentum (Sep 22, 2008)

Not that it's a big deal to work with SI units, but there's a certain "feel" that you don't have for SI units that you do for US Standard units. You instinctively know what a pound, PSI, gallon, foot, etc. are like.

But a Newton?, a Pascal? cubic meter per second vs. cubic ft. per minute?

I know in the Lindeburg practice exam, the problems that had SI units really messed with me. Not sure why, guess I was already used to where I needed to go for my unit conversions for Standard units. Or maybe it just got me out of my train of thought during a time I was already stressed out while doing the practice exam (and the Lingeburg one is really tough).

Also kinda hangs you up a bit becuase some of your formulas are different depending on if you are doing SI or US Standard. SO don't need gravity included, but US do. Little things like that I think are just one more distraction you don't need during the PE exam.

Forunately, I passed it last April, and I'm glad I did for this reason.

Just my 2 cents worth. Others are probably more comfortable with the SI units than me. BUt in the 10+ years between college and the exam, I use SI units only very rarely, and that could be why it seemed to get me sideways.


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