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

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In summary, the conversation discussed the units of measurement for a problem involving continuity and area. The question was whether the units were in m/s or mm/s, and the attempted solution involved converting all measurements to meters. The confusion arose from trying to maintain 3 significant figures while converting millimeters to meters. However, it was clarified that converting between the two units does not affect accuracy. Ultimately, the answer is in m/s.
  • #1
dcramps
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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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  • #2


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.
 
  • #3


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!
 

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

What is the difference between m/s and mm/s?

The unit m/s stands for meters per second, while mm/s stands for millimeters per second. The main difference between the two is the scale or size being measured. Meters are a larger unit of length compared to millimeters, so m/s would be used to measure larger distances or speeds, while mm/s would be used for smaller distances or speeds.

How do I convert between m/s and mm/s?

To convert from m/s to mm/s, you can multiply the value in m/s by 1000. For example, if you have a speed of 5 m/s, the equivalent in mm/s would be 5000 mm/s. Conversely, to convert from mm/s to m/s, you can divide the value in mm/s by 1000.

Which unit should I use for my measurement?

The unit you should use depends on the scale or size of the object or speed being measured. If the object or speed is relatively large, m/s would be a more appropriate unit. If the object or speed is relatively small, mm/s would be a better choice. It is important to match the unit with the appropriate scale to ensure accurate measurements.

Can I use other units besides m/s and mm/s?

Yes, there are many other units used to measure speed, such as km/h, mph, ft/s, and knots. The unit you choose will depend on your specific application and the standard unit used in that field. It is important to be familiar with the different units and their conversions to ensure accurate measurements.

Why are units important in science?

Units are important in science because they provide a standard and consistent way to measure and compare quantities. Without units, it would be difficult to accurately communicate and understand the measurements and results of scientific experiments. Units also allow for easy conversion between different measurement systems, making it possible for scientists from different countries to collaborate and share their findings.

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