Is the Answer in Meters per Second or Millimeters per Second?

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The discussion focuses on the confusion between using meters per second (m/s) and millimeters per second (mm/s) in a fluid dynamics problem. The user solved a continuity equation involving areas and velocities but was unsure about unit consistency due to the use of different measurement units. It was clarified that converting all measurements to meters is advisable for accuracy, and the final answer can be converted back to millimeters if needed. The importance of maintaining significant figures while converting units was also highlighted. Overall, the consensus is that the answer should be expressed in m/s for clarity and precision.
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Units -- is this m/s or mm/s?

Homework Statement


N/A

Homework Equations


Continuity
A1*v1=A2*v2

A=pi*r²

The Attempt at a Solution



I've solved a problem as follows

(pi * 10.0mm²)(0.200m/s)=(pi * 2.50mm²)(v2)
3.20 xx/s = v2

I am pretty sure it's in m/s, but having the radii in millimeters is confusing me. I would convert all to meters, but I am required to solve using 3sf, so I would lose accuracy on the 2.50mm.

Am I correct in thinking the answer is in m/s?
 
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You can never lose accuracy by converting millimeters to meters, and vice-versa, since the two are separated by a constant. You have the right idea - turn everything into meters, and if you want, you can turn the end product back into millimeters.
 


Heh, I converted 2.50mm to 0.025m and, for whatever reason, I got the idea in my head that I would have to reduce it to 0.020m to still have 3sf. I went back and did a bit of review on sf and figured it out :p

Thanks for the response!
 
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