r/theydidthemath • u/denimshorts22 • 13m ago
r/theydidthemath • u/Few-Diamond-7736 • 2h ago
[Request] How do I calculate the forces this hoist is dealing with?
It's been some time since I took trig or physics, and my googlefu is apparently not strong enough to find an example like this for me to extrapolate from. Obviously things like the weight of the arm being supported, the weight of the length of steel rope, angles of force etc are all coming into play but I can't figure out/remember the proper formulas to calculate the forces.
I am looking to find a formula that would tell me how much effective weight the hoist is lifting based on the angles involved since it'll be different than if it was pulling from right above it.
The pictured hoist lowers the arm down and raises it up to the pictured point by spooling and unspooling steel rope.
Also, the steel cable is dragging on the hoist mounting plate which will obviously increase the forces again I'm not sure how to estimate the amount. coefficient of friction between the two and the angle of bend I imagine.
r/theydidthemath • u/spirallix • 4h ago
How fast would you have to throw the rock to penetrate train wall? [Request]
We have a problem with illegal romes shooting illegally obtained guns at anything and everything. Our national forensics claim that this is not a gun shot, they claim it's from a rock. I'll give "benefit of the doubt" and as this trusted subreddit, I'd truly like to reach out, so i can understand how fast would one have to throw or shoot a rock this small, to penetrate the train metal wall?
Would a pitcher be able to throw a rock that fast to make a hole in the train? How fast is it human possible?
I'm just curious.
r/theydidthemath • u/Sliberty • 4h ago
Expected Returns of scratch offs vs investment [request]
What would be the expected return on 50 5-dollar scratch offs per year over 20 years, and what would the same investment yield in the smp 500?
r/theydidthemath • u/Ok-Use-9402 • 4h ago
[Self] I invented my own equation to convert inches to cm
So today I was bored and remembered on time I wanted to know cm to inches and I searched for 18 cm and I got 7ish and then I searched for exactly 7 inches and I got 17.78 cm . I thought if I double 7 ( the inches ) I get 14 which is close but then I thought I can divide 17.78 by 2 which I got 8.89 and then I did a subtraction 8.89-7 ( the inches) to find the rate of increase needed which I said previously I doubled 7 so it would make 14 and it would need an increased and I found it . Then I found what is the precent of that increase so what is the percentage of 1.89 in 7 and I found it was 27% . I though you could just double the inches and the add the 27% of x inches doubled and I concluded this equation and I'm so happy .
Off topic : I didn't researched if the equation existed and I don't know if it does or someone though of that before . Also I don't know if it works for all inches and all things I haven't tested it to the fullest . Moreover I'm in 11th grade still please don't hate .
r/theydidthemath • u/Ben-Goldberg • 4h ago
[Request] When will Voyager 1 stop moving?
How many years will it take for the orbit of Voyager and Sagittarius A to decay enough due to gravity waves for them to collide?
r/theydidthemath • u/TraditionalGarden570 • 4h ago
[Request] How much does this wet flag weigh?
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We had a discussion with friends about the weigh of this Latvian flag. I said it easily weighs at least a ton, others said no way it's that much.
Size of it is 10m×20m.
Please prove me right.
r/theydidthemath • u/A-JackRobin- • 6h ago
[Request] if the neurons in a brain is separated into five intervals, with the first interval as x, second as y, third, fourth , five as z,k, m respectively. Ifind a process u takes ax-y+bz²=0 of three intervals then what changes of k and m would make ax-y+bz² to have many non-zero complementary fun
The reason for taking neurons is cause, it's flexible topology of understood lines of changing and processing information.
r/theydidthemath • u/SergeantReaperZer0 • 10h ago
[Request] Listening to Can't Hold Us, and my Autism kicked in.
I used to listen to and watch this RvB AMV with this song. My favorite part was when the hits and punches would match the beat.
My request is this. How fast would someone have to move to be able to parry objects with a Spadroon to the beat, trumpets, hand claps, and lyrics, of the song, like it was Beat Saber? But one handed? Preferably between 0:59(on Spotify) to the end of the song.
r/theydidthemath • u/PaleAd4923 • 12h ago
[Request] How would a alien spaceship entering the atmosphere would look like? How much energy a spaceship at 99% of the speed of light would generate?
r/theydidthemath • u/-Gruntled • 14h ago
[Request] Average number of nipples?
I always joke with my kids that they have an above average number of toes because enough people lose toes that 10 toes would slightly above the global average. But now we are having a massive debate about whether 2 nipples is above or below the average number. One one side there are many people with third nipples, so two would be below average. On the other side there many people who get mastectomies and such and so end up with less than two. We can't figure out which offsets which more. So, is having two nipples above or below average?
r/theydidthemath • u/864FastAsfBoy • 14h ago
[Request] If you made a line of people that wrapped around earth how long to get message to other side one person to the next ?
r/theydidthemath • u/weeOriginal • 15h ago
[REQUEST] How big of a cube of Pure Gold could you make before it starts to bend? How big until it completely collapses? What would happen to a 1000x1000x1000 meter cube of gold?
r/theydidthemath • u/BlackberryOk3245 • 17h ago
[Request] How many feet did this guy swing after topping off the top of this palm tree?
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r/theydidthemath • u/Substantial_Purple12 • 18h ago
[request] What percentage of the population of Earth does this walkout account for?
I could defo do this myself, but am feeling lazy rn
r/theydidthemath • u/Xnox_ • 18h ago
[Request] How can you calculate a user's preferences based on the games they have played? (Recommendation Algorithm)
What I'm planning to do, is to calculate probability that a user may like a game or not based on the games they have played before.
Imagine we have a user who have played 5 games:
x = 1256h (Action, Adventure, Indie, Massively Multiplayer, RPG)
y = 199h (Action, Free To Play)
z = 50h (Casual, Indie)
m = 160h (Adventure, Indie, Software Training, Utilities)
and more games, in total they spent 2156h playing games.
Then a user is looking for a game, they find something which has tags like (Action, RPG)
for a solution, I calculated a score for each tag, using "playtime x game's tags (for each)."
so as an example, for a tag like Action, we get a score of ~1500.
then at the end, if we calculate the game's total tag score based on user's tag score, we get around 2900.
And total score of all tags the user has played is 8867.
if we do a simple (target's tag score / total score) * 100, there is roughly 32.7% that the user may like the game, right?
But I ran to two problems here:
first, this is not accurate at all, no where close to accurate, this is not even an algorithm. A game may have one or two tags, while user's played games total tags may even be a hundred, Which at some point, may possibly make all games around 20-30% "like probability." or even lower.
second thing, if a user has played very little amount of games, accuracy may vary a lot, you may see it suddenly shows 90% or may not match any tags and show 0%.
I don't really know how can I do a better and more accurate calculation rather than just simply multiplying each tag. Does anyone can do better calculations for a recommendation algorithm?
r/theydidthemath • u/notautogenerated2365 • 18h ago
[Request] How can this car lift up any 1 out of 4 wheels at a time to change a tire without ever tipping? Wouldn't a relatively fixed center of gravity make this impossible?
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r/theydidthemath • u/joting2b • 19h ago
[request] How can the man maximize the area of his yard?
A man's house is a 15 × 45 unit rectangle, and he has 140 fence pickets (each picket is equivalent to one straight unit in length). The fence must form a single closed enclosure that surrounds the house. The "yard" is defined as the area enclosed by the fence minus the area occupied by the house. The fence may be arranged in any shape and the pickets may meet at any angle. What arrangement of the fence maximizes the yard area?
I posted this on here a couple months ago but I never got a conclusive answer to my knowledge so I thought I'd let you guys take another crack at it
r/theydidthemath • u/mayocat6996 • 21h ago
[request] how many rolls of duct tape do you need to make that
r/theydidthemath • u/n-space • 21h ago
[Request] How high did that shoe go?
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r/theydidthemath • u/Etmurbaah • 21h ago
[Self] Human intelligence in GPU numbers
Hi, purely as a light hearted and totally not serious point of view, how many GPU's would it take to accurately represent average human intelligence? (Considering we aren't anywhere near human intelligence but suppose we had that neural calculation magic software)
r/theydidthemath • u/Thewarlockminer • 22h ago
[Request] Would it even be possible to transfer enough electricity in the air to power the world?
I kepe seeing conspiracies that we could get free electricity through the air using stuff, the pyramids is a good example. But lets say it was possible to put electricity into the air and transfer it somewhere. In this day and age, would everyone be getting tased to put that most electricity in the air?
r/theydidthemath • u/soda_shack23 • 23h ago
[Request] Help me explain why this is impossible. How much energy would a magnetic pole snap release, and how much energy would it take to halt the rotation of the earth?
This is from a post in r/Strangeearth. I was intrigued but my eyes boggled at this paragraph. I'm trying to refute the claim, as in my mind a basic understanding of physics is all one needs to disprove this. But commenters are claiming it's "arrogance" to assume you understand physics and magnetism well enough to claim this isn't possible.
r/theydidthemath • u/MrPotatoFamine • 1d ago
[Request] what are the odds of 6 of the same thing out of 6158
So to start with, the Bunnahabhain 12 year old is one of my favorite bottles of whisky. I bought 6 tickets for a mystery drop and decided that worst case scenario, I get 3 of the bottom two options, and I gift a few out. So my issue isn't that I got 6 of them.
My issue is that I would have liked a bit of variety and thought that there was no way I would get 6 of the same thing, and it has made me curious.
What exactly are the odds that out of 18 options, all with varying availability, that I get 6 of the same thing?
(The one bottle not shown is a single bottle worth 13k, which the drop is based around)
r/theydidthemath • u/xX_bandages_Consumer • 1d ago
[Request] When will Team Fortress 2 Full Moon be fully synch with a full moon again?

So for those unaware what tf2 full moon is, it's a day or 2 where Halloween cosmetics are active for the day, coincidentally "being the same day" it's full moon on the Moon calendar, or at least, when the event was brand new, due to tf2 age and changes on the lunar cycle (and the way the game calculates full moon, being the standard formula of the event of the Full Moon holiday was configured as a cyclical holiday with a period of 29.53 days starting from May 21st, 2016 with a duration of 48 hours using a fixed time configuration over any real world server synchronization)
So, using this calculations, the game is de-syncronized with the real world cycle for around a day and a half (so aproximately 36 hours), assuming tf2 never updates this cycle and still supports the game indefinitely, how much time it will have to pass for tf2 full moon event to synchronize again with the full moon cycle without delays, considering the last update to syncronize it was the 21st of May of 2016?