# Tag Info

0

This is equivalent to the question of two people carrying a sofa (or plank or any long object at opposite ends): does the shorter person have to do exert more effort? The answer is yes, if one support is lower than the other with respect to the center of gravity of the load, it will experience more of the load. In the push up position the higher the feet ...

-1

Nice to see a biomechanics question on here. Its a bit tough to answer the question not seeing just how far off the ground they are, what the "apparatus" is, or how far over the edge their legs are, but I think I see the underlying question. From a purely physics point of view, there's no reason why any aspect of a Pilates exercise would be more difficult ...

0

Well it depends upon size of the event, and its distance from earth. If the same event that LIGO captured, had taken place a couple of light years from earth, it would have been observed much easily, may be by human beings without any instrument. But that could have also caused other hazardous effects which is not the point here. So, it is energy, and ...

0

The gravitational waves observed recently came from the most powerful sources of such waves currently available for observations - collisions of black holes. They still were detectable with great difficulty and aid of powerful, precise equipment. Conclusion is as follows: Apparently there currently exist no gravitational waves so powerful that they could be ...

3

The probable reason why poeple say ice cream heats up your body is when you compare the amount of heat that it takes away your body compared to the food caloric value of the ice-cream. 100 grams vanilla ice cream is about 207 food Calories ($207 kcal$) according to this site. On the other hand, the amount of heat that the ice cream takes from the body is ...

2

From the last email of the particle data group : The 2016 edition will be published in summer. PDG Books containing Summary Tables and review articles as well as Booklets will be mailed in fall. Starting this year, the Data Listings will only be published online.

4

One very popular view (as espoused by Max Tegmark) is that (quoting count_to_10) : math works because the universe is based on math http://www.scientificamerican.com/article/is-the-universe-made-of-math-excerpt/ https://en.wikipedia.org/wiki/Mathematical_universe_hypothesis Such a view was common from the time of Pythagoras, through to Kepler and ...

1

The simplest way I can think of correctly defining quantum physics is that it is the combination of our best and most correct theories of physics that does not include General Relativity. There are two relevant and important classes of physics for this explanation: classical physics and quantum physics. Physicists are people too. If we can achieve our ...

5

As you are talking about a "Star map" and "current visible positions", I'll assume you are talking about a star map of the ${\sim} 5000$ stars visible to the naked eye. Most of those stars are within 1000 light years of he Earth. They have typical velocity dispersions with respect to the Earth of ${\sim} 10$ km/s, with the occasional rare star with a ...

0

I suggest Group Theory in a Nutshell for Physicists by A. Zee

3

Disclaimer: i understand you didnt ask about gauge invariance but gauge invariance and vector potentials are connected and so ill discuss both in my answer below. Schwartz "quantum field theory and the standard model" has a good, albeit very brief, accessible discussion of the utility of gauge invariance, in particular the vector potential. Gauge ...

0

No, a physical theory can never be "proven". There is a classical metaphor to illustrate why, known as the black swan problem or problem of induction. If in your entire life you have only see white swans, you will formulate the general law (or theory) that all the swans are white. You will then keep seeing only white swans -thousands of them- and think "my ...

1

I would not agree that a theory is the same as a hypothesis. Rather I would argue that hypotheses are formulated within the framework a theory. Theory refers to the whole body of knowledge, usually driven by observations. The statements of a theory are validated by empirical data. Theory provides names and concepts for the observations so that scientists ...

4

In a strict true/false sense, every scientific statement is false. For example, the following two statemaents are both false: The Earth is flat. The Earth is a sphere. However, the second statement is much closer to the truth than the first. [1] It is this kind of closeness to truth that distinguishes a scientific hypothesis from a scientific theory. In ...

5

The sentence, as it is quoted, seems moot to me. In fact, it would apply to any logic theory: a logic theory is nothing else that a collection of statements assumed to be true (axioms/hypotheses - the name is not so important), and a collection of logic symbols and rules of inference (also assumed to be true) that codify how you can get new true sentences ...

3

Please note that this is not so much an answer as an extended comment. At this website (which is the Google Book website for Contemporary Newtonian Research by Z. Bechler) it says It is well known that Newton became convinced towards the end of his life that electricity played a vital role in the operations of nature. In the famous final paragraph of ...

1

I think you are asking far too much of one book, and your requirements are somewhat contradictory. Books for the layman are not usually "in-depth." It is up to you to define what you consider to be "major" and what topics you would like to read about. If you do not do so, we can only guess. Books on the detailed history of physics usually specialise in ...

0

One book I'd definitely recommend is John Gribbin's The Scientists. While it is a little more biographical, it does include the trial and error, the buildup, etc., as well as the stories of quite a few more obscure scientists that contributed way more than you'd think. His book is also in a narrative format, not an encyclopedic format. John Gribbin's book ...

1

I want to add an answer which I think supplements some of the other comments. @lemon notes that "gravity" refers to the pull towards the Earth while "gravitation" is more general, but notes that this is archaic. In fact, it is a very old term and the history is interesting, so take this as a "history of science" type answer. Disclaimer that all of what I ...

0

That's incorrect definition propagated by text books for simplicity sake. Gravity should always be defined as a force that attracts a body towards another physical body with mass. For simplicity sake, gravity is taught as the force with which Earth pulls a body.

Top 50 recent answers are included