I have a question about force. According to newton's second law $F = ma$ , we already setup standard and devices for measuring distance and time so that we can calculate acceleration using these.
But there are two unknown terms remain to calculate if we take standard measurement of force we can calculate mass and vice versa. In this what is standard Force or Mass?
1 Newton is by definition the constant force you need to accelerate 1 kilogram of mass with a constant acceleration of $1\frac{\mathrm{m}}{\mathrm{s}^2}$
note that Newton, meter, etc. are called units and not "standard measurements"
but getting exactly N atoms of a 100% pure substance is rather difficult, while measuring Planck's constant is much easier
Look at the meter and the second. If you can accept defining the meter via the speed of light and the second, then you must also accept defining the kilogram via Planck's constant, it's the same principle
Given a closed 2-dimensional conducting loop, the terminals of a battery are connected at any two points on the loop (but not the same point).
As an example, consider a circle of radius $R$; the two terminals of the battery divide the circle into two arcs. Let one arc subtend an angle $\theta$ at...
you need to define $A$ and $B$ separately before you can talk about $A$ being proportional to $B$
In most circumstances, I would view $F = ma$ as the definition of force
it makes no sense to talk about perhaps writing $F= kma$ with some unknown $k$ - unless you have a different definition for $F$, you're free to choose $k$ and this just changes your definition of $F$
@ACuriousMind I have read his answer one week earlier but now after your sharing i am reading it very carefully. Thanks
I have also read in book by Robert Hanlon they said newton's law is not give us the definition of force it gives us effect of force as things are happening in cause-effect.
@ACuriousMind If bus is moving with constant acceleration rightward we feel force leftward to change our state. But why in free fall we won't feel upward when falling downward???
now I wonder, @EVO - are you colorblind, do you have really bad color settings on your display, or has your native language different color descriptions from English and 'red' was a guess for the translation of what you really wanted to say?
for a change we can go into this https://en.wikipedia.org/wiki/Linguistic_relativity_and_the_color_naming_debate instead of the usual debates on "general covariance/invariance", "active vs passive transformations" etc :P
@ACuriousMind they could also have some night mode/blue light filter on, that could make white look yellow and yellow more reddish
@fqq I do find it really fascinating that we all take colors as "obvious" but there's really nothing except convention that determines what colors count as "different"
> This article is written like a personal reflection, personal essay, or argumentative essay that states a Wikipedia editor's personal feelings or presents an original argument about a topic. (September 2011)
For those curious about their colour vision, try the free X-Rite Color Challenge and Hue Test. It only takes a few minutes. If you're using a blue light filter, turn it off before you do the test.
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@satan29 Just use the normal Markdown link syntax [Link description](URL)