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13

This depends on the context. If you have 1500 of something and you counted them yourself and you are sure you have precisely 1500, then all four figures are significant. On the contrary, if you're guessing that you have 1500, implying a certainty of order 100, then only the leading two figures are significant. In scientific notation, one would write the ...


9

I teach high school in the United States. I want to preface with that, because conventions common in one context are not necessarily universal. That being said, it's pretty standard teaching practice here (at least in every class I've ever taken, taught, or known a colleague to teach) to assume that trailing zeroes are not significant unless otherwise ...


4

The temperature is not measured in the sense of using a thermometer. Instead it is calculated from the velocities of the particles in the trap. Temperature is related to the velocity distribution by the Maxwell-Boltzmann equation. Under normal circumstances we are usually starting from a known temperature and calculating the velocity distribution. However ...


3

You are completely right, it is a confusing case you have. The number $1500$ does have 4 significant figures as it is. But, you are told it has only 2. This is strictly speaking not correct. But it is just a shorthand way of writing $1.5 \times 10^{3}$ (or $15 \times 10^{2}$). It is an easier way to write a number with not so high an order of magnetude. ...


3

In physics, all numbers are imprecise. Significant figures are conceptually the digits that it is meaningful to include in the reported result. The concept When you read a gauge, the reading error is half the smallest interval on its scale - you basically take the value of the tick nearest to the hand's position (digital gauges do this for you). So, if ...


2

I would maintain that we most often explicitly measure mass by comparing the pull of the local (unknown) gravity on the mass to be measured to the pull of the same gravity on a known, reference mass or masses. If you look at the measuring devices in stores, you sometimes see the slogan, "Honest weight; no springs!" They are proudly claiming that they are ...


2

I was thinking how, since an object in our universe can move from one position to another, it must have passed through all the positions between those two positions. (I am thinking it moved it a straight line) This must mean that in actuality there are only so many positions between those two points doesn't it? There must be some maximum accuracy to ...


1

I hope someone with more knowledge will pop into thread, but here is my education. There might be number of ways to measure such low temperatures. One I find fascinating is starting with material, namely Bose-Einstein condensate. Reference is this one: Cooling Bose-Einstein Condensates Below 500 Picokelvin, Leanhardt et al. Science, 12 September 2003. ...


1

There's a lot of context that goes into deciding which digits are significant. I like to use the "anger management method" for deciding which digits are significant. Suppose you are shopping for a fancy television. You see an advertisement that there's one you like on sale for \$1369.99. You know that your area has 10% sales tax, so you predict that when ...



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