Given weight = mass * gravity do I weight less during high tide and more when tide recedes?  My guess is weight = mass * gravity * gravitational pull of moon factor
Using $g = \frac{Gm}{r^2}$, the force on a point mass located at 1 AU from the Sun ($m = 2 \cdot 10^{30} \text{ kg}$) is about ~0.006 N/kg.  Does that mean that, e.g., a 70 kg person is ~42g lighter during the day, and ~42g heavier at night? That seems like it could make a big difference for things like measuring gold bars or other weight-sensitive items. (Gold arbitrage: buy your gold during the day and sell it during the night! Risk-free profit!)  This makes me suspect that I'm overlooking something obvious, because a ~0.05% weight difference seems like something everyone would have noticed long ago. So what am I missing?    Edit: A few answers below indicate that there shouldn't be any weight difference, because the Earth orbits the Sun in free-fall. But if that's the reason, does that mean that a 1:1 tidally-locked Earth-Sun system wouldn't experience differential gravity from the Sun on opposite sides? That doesn't seem right.
Are there any examples of $\frac{a}{b}+\frac{c}{d}=\frac{a+c}{b+d}$? I am writing a short discussion of Farey numbers and was wondering if there are any examples of when the mediant function is ever actually equal to the sum of the two fractions in the usual sense? (Not to produce Farey numbers, I just thought it might be an amusing way to introduce Farey addition).   Explicitly: Are there any examples of fractions $\frac{a}{b}$ and $\frac{c}{d}$ where  $$\frac{a}{b}+\frac{c}{d}=\frac{a+c}{b+d}$$ for positive integers?   Currently I have found the example  $$\frac{1}{1}+\frac{1}{i} =\frac{1+1}{1+i}$$ if we remove the integers requirement but it would be nice to find a case that didn't involve complex numbers though! Polynomial rings in infinitely indeterminants How can we prove that (the set of all polynomials in infinitely non commutative indeterminants over $k$) is a ring, where $k$ is a ring with unity?   Adding two polynomials is a polynomial, but for commutativity  How can we show the following: $ax_1+bx_2=bx_2+ax_1$ (commutativity of addition) If we have finite number of variable it is easy to prove it, (we take the $n-1$ variables...), but what about the infinite number of variables?  Can someone give me a hint? Why is "No new release found" when upgrading from a LTS to the next? Calculating percentage of overlap between 2 features from 2 different layers using ArcGIS Desktop? I have two layers. Layer 1 has features that are property/parcels with area in acres. Layer 2 has features that are wetlands/bodies of water with area in acres. I want to calculate parcels that have for example 0% wetlands, 10% wetlands, 20% wetlands, 30% wetlands etc. to 100% wetlands.   How can I do this on ArcGIS Desktop?   Ideally, I want to find parcels/properties that have a limited number or a limited percentage of wetland coverage. What does "Baking" mean? I want to make some cool items for Dota 2 and I'm reading a guide. There are some tips about baking  etc. but I can't use them, because I don't even know what baking means. Can somebody explain this, please?  Thanks for all answers. How to relate combinatorial proof to bipartite graphs? The question is - Let $k \geq 1$ be an integer and consider a sequence $n_1,n_2,\cdots,n_k$ of positive integers. Use a combinatorial proof to show that  $\binom{n_1}{2} + \binom{n_2}{2} +\cdots+ \binom{n_k}{2} \leq \binom{n_1+n_2+\cdots+n_k}{2}$  How can i prove this without using induction?  Additionally, For each $i$ with $1 \leq i \leq k$,consider the complete graph on $n_i$ vertices. How many edges does this graph have?  I thought of making graphs and figuring out a relation but still wasnt able to. Rotate whole animation by 90 degrees I make my animation and now I realized that its pointed in wrong direction I used -y (native blender) as direction but I need to be pointed at x axis so what would be the easiest way to rotate whole animation, to switch -y with x :) Proof of the Hockey-Stick Identity: $\sum\limits_{t=0}^n \binom tk = \binom{n+1}{k+1}$ After reading , the most popular answer use the identity $$\sum_{t=0}^n \binom{t}{k} = \binom{n+1}{k+1}.$$  What's the name of this identity? Is it the identity of the  modified.  How can we prove it? I tried by induction, but without success. Can we also prove it algebraically?  Thanks for your help.    EDIT 01 : This identity is known as the  because, on Pascal's triangle, when the addends represented in the summation and the sum itself are highlighted, a hockey-stick shape is revealed. How to write special set notation by hand? "Delete this answered question?" when the only answer is deleted Looks like there's a small bug in the UI: I posted a question here on meta.SE which ended up being just something dumb I was doing and no use to anyone in the future. At first I posted an answer saying what the dumb thing was, but then I realized that the whole thing had no value, so I deleted the answer, and then deleted the question — whereupon it asked me:  Delete this answered question? We do not recommend deleting questions with answers because doing so deprives future readers of this knowledge. Repeated deletion of answered questions can result in your account being blocked from asking. Are you sure you wish to delete?  (Screenshot below) Probably shouldn't ask (or add to the tally) if the only answers are deleted ones... A story about a whole crew of aliens who visit Earth, befriend a child It was a book I read when I was a kid, so I am assuming it was a book aimed at kids/young adults. A whole crew of aliens of different species meet an Earth kid. He befriends them. One of the aliens comes from a planet with dozens/hundreds of different sexes/genders. At one point, the Earth kid is talking about a swamp:  Alien: &quot;I live in/near a swamp on my home planet&quot; Kid: &quot;Oh, do you come from a swamp planet?&quot;  The alien points out that just because there is a swamp on his planet doesn't make it a swamp planet, there are dozens of biomes on his planet, just like Earth. Earth isn't just a swamp planet. The banner ads are in the wrong format for the right-hand ad slot:    These kinds of ads are not useful (because most of it is cropped) and should be excluded from being shown in that spot. How to determine capacitance I’m looking to install a capacitor in a circuit which runs at 12V and &lt;10A, and I want it to discharge in about 3 seconds.   The discharge voltage isn’t too important, but it’s probably best if it is as high as possible (not higher than 12V if that is even possible) for those 3 seconds.  The discharge time can be longer but probably should have an absolute minimum of 1.5 seconds.   Sorry if this sounds like gibberish. If I'm not giving enough info, please let me know what else i need to provide. I’m not an electrical guy; just working on a project and have no clue what I'm doing. Looking for the title of an old sci-fi book, pretty sure it is a Baen or Del Rey imprint. Basically, mankind has reached the stars and expanded throughout the galaxy. Suddenly, an unknown race appears and begins a war of extermination against man. Finally, the galaxy is desolate, and one man remains. He is in a starship with an AI and becomes injured in the battle.  The ship's AI takes over and speeds out into the unknown, followed by the last remaining member of the unknown alien race. As all speeds are at tremendous multiples of the speed of light, the man cannot get away, but the alien cannot catch up.  Finally, communication is opened, at which point the man asks "why?" The alien tells him that man had discovered immortality, but that it required the death of a member of a race known as the Flower People for every human who achieved immortality. The alien says that Man would have found the answer eventually, but that genocide was so intolerable that the aliens came from another dimension, to which they could never return, to stop Man, which resulted in the war of extermination.  Finally, the light speeds become so great that the two remaining living beings in the universe approach the Big Crunch. As the Man begins to dive into the singularity, with the alien hot on his heels, he says that maybe there will be room in the next universe for both races to live in peace, and the final line is "not with a whimper, but with a roar of triumph"! How do I check an iOS device's battery health? What is the origin of non-conservative force? My understanding about  is a force that its work is independent of path such that we can construct another form of the work called potential to make our life easier.  For friction, if I start from microscopic point of view, it should be the macroscopic effect of the electric force or gravity which are both conservative force.  Why do we initially have description by conservative forces (electric/gravity force) but end up with a macroscopic description of nonconservative force(friction)? Suppose I want to know whether $\sqrt{7}\in\mathbb{Q}_5$, or more generally, whether $\sqrt{n}\in\mathbb{Q}_p$ for $n\in\mathbb{Z}$, $p$ an odd prime. What are the techniques for determining this? Am I supposed to "lift" it from $\mathbb{Z}/p\mathbb{Z}$ using Hensel's lemma? Could I see an example? How can I take screenshots of YouTube videos in full screen? I am trying to take a screenshot of a YouTube video in fullscreen.  When I pause the video and wait a moment, only the bottom UI bar (play/pause/seek) disappears. The top UI bar (Like/Share/More Info) stays there.  So when I press PrintScreen on the keyboard, the screenshot is polluted by this top UI bar. Is there any way to remove it while the video is on pause? Replacements for switch statement in Python? Can I open a US bank account even if I don't live in the country?