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Nothing is wrong. If in your experiment, the tape is placed parallel to the rails in such a way that when the train passes (A), it grabs the tape and it "sticks" along the train "instantaneously", then the following happens: A person in terrain, before (A) sees a static normal-size tape and a contracted train approaching fast, after (A) he/she sees the ...


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After some significant research, I have figured out how to do this. You make a linear measurement array using precision 1.0000" balls in right angle v-groove with a base plate, and then a matching block at the top. If this is done carefully, you can even reach 1/1000th precision. It looks like this: Everything has to be scraped and square, especially the ...


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Of course the force changes during the impact - so to get close to an answer, you need both the time of the impact and the magnitude of the momentum transfer. As user77567 pointed out, a fairly simple way to measure momentum transfer is with a ballistic pendulum. This would be a heavy steel ball (much heavier than the hammer) hung from a long wire. When you ...


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 ...


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 ...


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$$s=k_B \ln(v_2/v_1)^N$$ so if you are able to measure all the quantities present in this equation, you will be able to measure entropy. Here, $k_B$ is the Boltzmann constant and $N$ the number of molecules in the system.


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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 ...


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. ...


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 ...


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 ...


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There are objects in the universe yet to be discovered as shown by constant new discoveries of new types of planets under conditions that were previously considered impossible. (Diamond Planet, Fire Ice Planet) I believe this works the same way with objects in motion as well. If the Big Bang theory is correct, and our current interpretation of how physics ...


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I am not a physicist (my background is biotech) but from a non-technical perspective I believe that since the centrifuge has no gravitational field (it operates in the same part of earths gravitational field as the observer) then the only time dilation that might be measured would be due to the velocity of the test subject rather than the g-forces created by ...


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amp meters would not work as they display the instantaneous current consumption...what you need is to monitor the integral of i^2*R where R is the resistance of the water heater in Europe (UK or Germany), your electricity company would give you a so called smart meter. this has a clamp current sensor that can be connected around the power cable going to the ...


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I put a cesium clock in a centrifuge for 24 hours, got 45.9 microseconds first relative to gps satellite. 20,200km up Centrifuge spun at 2 G's it was 91.8 microseconds. You can suck on numbers all you want, but experiments don't lie.


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. ...


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 ...


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On the screen you will detect particles always. But they won't form fringes, when you disturb them. If you do this before the slits edges, the result of seeing fringes or not depends from the result of your disturbance. For example, if you broaden the light beam, you are working against your apparatus which contains a collimator or a point-like light source. ...


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You could use cylindrical hollow capacitor and electrical bridge circuit and measure changes to the capacitance when the metal balls passing through it. As the ball pass through the capacitor, its capacitance will change due to the change in the dielectric properties inside the capacitor. The changes to the capacitance will be a function of the size of the ...


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Is the probability $|c_1|^2 + \ldots + |c_k|^2$? Yes or no. It happens $\frac{|c_1|^2 + \ldots + |c_k|^2}{|c_1|^2 + \ldots + |c_N|^2}$ fraction of the time in the long run. (Assuming the states you listed were all normalized.) What state does the system jump into after this measurement? There is no experimental evidence of jumps or anything discontinuous. ...



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