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15 votes

If gravitation is negligible for small masses, how was Cavendish's experiment successful with balls much smaller than celestial objects?

Of course Cavendish had to put those small masses much closer together than celestial objects (usually) are. But that was not enough... The masses to detect the force had to be suspended by a long ...
Jos Bergervoet's user avatar
7 votes

If gravitation is negligible for small masses, how was Cavendish's experiment successful with balls much smaller than celestial objects?

Gravitational forces are indeed negligible for small masses in everyday life. We just don't carry around with us detectors that are sensitive enough to register those forces, which are far far too ...
niels nielsen's user avatar
7 votes
Accepted

Are zeros to the right really significant?

Zeroes to the right are significant in error analysis. This is because when you make a measurement, you make an error (usually because your measurement device is not precise enough). The number of ...
Gabriel Ybarra Marcaida's user avatar
6 votes

If gravitation is negligible for small masses, how was Cavendish's experiment successful with balls much smaller than celestial objects?

To make a more general point, "negligible" is not the same thing as "non-existent". What allows anything to be negligible is the context. There is nothing that is universally ...
BioPhysicist's user avatar
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3 votes

Does changing units affect Significant Figures

Does changing units affect Significant Figures It should not. There will always be a doubt about the significance of the zeros other than as placeholders with values greater than $10$ like $60\,\rm kg,...
Farcher's user avatar
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2 votes
Accepted

Suppose we observe a photon, what can we measure about it?

First, you can measure the fact that the photon is there, for example a "click" in a Geiger counter. This might seem a little philosophical, but many experiments boil down to counting ...
Andrew's user avatar
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2 votes
Accepted

The Principle of Homogeneity of dimensions states that you can add,subtract quantities with same dimensions but we cannot add a constant with an angle

Dimensional homogeneity principle should be interpreted like so,- that you can't compare or equate two quantities if they have different dimensions (like distance to speed). If they have same ...
Agnius Vasiliauskas's user avatar
1 vote
Accepted

Vernier Calliper Reading and significant figures

$n$ should be taken as zero only but no it will not reduce the number of significant figures. The reading in your case will be recorded as $4.00$ and will have $3$ significant figures. Least count of ...
Yash Shrivastava's user avatar
1 vote
Accepted

How to add and subtract significant figures?

The correct way to add or subtract significant figures is the way that your instructor teaches. Significant figures are not used by professional scientists at all. They are only used in introductory ...
Dale's user avatar
  • 102k
1 vote

States of entangled particles after no/partial/full measurement

The answer to this question involves what interpretation of quantum theory you're using so I'll describe the options. The Copenhagen and statistical interpretations say that quantum theory doesn't ...
alanf's user avatar
  • 8,091
1 vote

Why is the uncertainty of the Gravitational Constant $G$ many orders of magnitude larger than that of other important fundamental constants?

Of all the fundamental forces in nature, gravity is by far the weakest, which makes it hard to set up an experiment in the lab where you can accurately measure G (which is a tiny number). Consider ...
niels nielsen's user avatar
1 vote

How were angles measured in ancient times?

One degree is defined as $\frac 1 {360}$ of a full revolution. If you are creating a measuring instrument it is probably more convenient to define it as $\frac 1 {90}$ of a right angle or $\frac 1 {60}...
gandalf61's user avatar
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