Physics

I say "without a motor vehicle" because I know there's light aircraft you can get that would cost an amount comparable to a personal motor vehicle. But I'm discussing this; mostly as a thought experiment; as to whether or not there's wings you could attach to your arms and achieve lift by acquiring a high enough speed without a motor vehicle. (Let's say, rolling downhill in roller blades or a skateboard or something like that. Presumably also wearing protective body armor with springs in case anything goes wrong.) For instance, suppose you had encased your arms in wings designed in a similar shape to airplane wings. What would the scaling effects be? Would the…

Anyone able to help me understand if this makes sense? A scenario someone proposed and I have reservations about. A gas cylinder - fill estimated ~170L compressed gas, plus steel cylinder + aerial harness (unclear weight) - is falling. Let's say it hits the upper corner at ~50 m/s, and slows to 30 m/s before hitting the balcony floor. Not shown: the aerial harness with fins are on at first but removed somewhere on the way, left badly crumpled. It's designed so the thing falls nose/valve first. Both the corner impact and subsequent impact through the balcony floor are presumed nose-first, but not necessarily 100% vertical. Then somehow its falling causes THE SIDE o…

https://www.cia.gov/library/readingroom/docs/CIA-RDP96-00791R000200180005-5.pdf I feel uncomfortable with the idea. I mean even publicly speaking about it makes me seem crazy, I just want to know if any researcher has ever tried to correlate or research it further? I am not a Science guy, I am not a Stone Magic Mom and I am just curious on what you guys think. I know it is in Public widely regarded as Pseudo Science, even I am still in full skepticism, but since yesterday I got sucked into an Alex Jones like Rabbit hole regarding the Remote Viewing Experiments of the US government in the 70s-90s, after I had watched the badly edited but well pr…

Hello all. Squeezing with a fixed force a water filled bladder, water exiting trough a orifice causing underwater propulsion as a squid/octopus does. If the orifice is small, the jet exit velocity is faster and the time to deplete the bladder is longer. A larger jet exit orifice produces a slower jet velocity of larger mass for a shorter time until the bladder depletes. Which orifice provides more propulsion (as to reach further, not faster ?) How does nature selected the optimal orifice size for the octopus need ? Proportionally to the size/mass of the growing octopus ?

Hi all. A spear mass is 1 Kg. If gravity g is 9.81 m/s² on this planet, its weight is F=mg = 1 x 9.81 = 9.81 Newtons. Is that right so far ? That same spear of 1 Kg underwater weighs 5 Newtons. Does it mean that the acceleration of gravity is not exactly constant in this planet as it would be then, g = F/m = 5/9.81 = 0.51 m/s² because differs underwater, part of this same planet ?

Hello: I'm working on a difficult problem. Imagine a wheel, dangling from an axle, allowed to spin freely. If you tape a weight to the rim of the wheel, then that section of the rim will rotate to the bottom, right? Now ... Imagine the axle is not perfectly in the middle of the wheel. That "Offset" (or runout) will cause the wheel to rotate, even if the wheel is perfectly balanced around it's true center point. My question is this: How much offset (runout) will be equal to adding 3 grams of weight to the wheel, 0.216 meters from the exact center of the wheel. Weight of wheel: 19000g (19 kg). Diameter of wheel: 0.725 meters Assumptions: No fri…

Ever since learning to integrate in high school Calculus, I've been curious as the the physical meaning of the integral of position w/ respect to time. Over the years, the topic has come up again and again in my mind, and have finally decided to put an end to my pondering; or at least let others ponder with me. Is there any firm grasp of the concept of the meter-second already in existence? Is there a good use for this? I have come to call the integral of position wrt time "longevity" as that seems to be the best term in my mind to describe it. From what I have been able to determine with some simple thinking is that longevity can be related to amount of energy or…

Although it would be a leap of faith, how reliable would it be for a human to strap on an easy to wear magnetic jacket/belt and jump down a strait tube of which the temporary Eddie current would slow the person down according to Lenz's Law so they would reach the end of the tube at ground level reliably and without injury? Sort of life a Fireman's Pole, only without the pole.

Essentially though, if you logically think about it.. light does not "travel" its a rate of propagation. and i'm not into conspiracies.. however it makes much more sense! 🤔

I can't imagine that gravity will ever fade away, but what about the strong nuclear force and the electromagnetic force? Do they have an expiration date? Will atoms one day lose their energy and fall apart? If not, how is it possible for them to preserve their energy?

why is it not possible to isolate an atom to measure its radius? There are many works in chemistry which require isolated atom for example in wave functions.

Hi. How many kilowattshour are needed to create 1 Kg of hydrogen ? ----> https://news.stanford.edu/2019/03/18/new-way-generate-hydrogen-fuel-seawater/ Do not see much news of the electric vehicle Quantino these days . Another flop ?

https://www.youtube.com/watch?v=ci8ZXxYDajQ So in this Southland scene, a stolen taxi is aimed directly at a police car and driven toward them for a head-on collision. The cops swerve to avoid this. I'm just wondering now; is there any way to deploy spikes in the front of police cars, with springs behind the spikes, such that the engine and/or tires of the vehicle in front of them can be punctured, while the springs absorb the impact so the car's speed doesn't change as abruptly as that of the vehicle in front of them? That way, if this sort of thing happens in real life, they can deploy the spikes instead of swerving and stop the criminal sooner.

When I ask google how is the spin angular momentum of an electron measured, it points me to the Stern-Gerlach experiment. Yet, I figure, it cannot be the only way... As I understand it, the Stern-Gerlach experiment actually measures spin magnetic moment, but I guess there is some other way to measure the spin more directly - how else would we know the 'g' factor of an electron?

Hi! I remember a story about two diffrent laboratories. One was in Switzerland as far as I can recall. The swiss lab continiously produced better research than the other lab. Nobody could think of a reason for that, they both had top notch equipment and research. it turned out that the swiss (if i recall it right) was better because it shared a canteen with the biology? department. Does anyone know the labs, or maybe a report about this situation? It seems impossible to find it on google with the vague information I can provide. Thank you for your time and thoughts. Best, Moritz

Hi. What happens to common materials in the vicinities of a nuclear accident where neighborhoods have to be evacuated, decontaminated, cleaned ? Is it like a -say house- got 'sprayed' with what?; the wind brought what and deposited it where? towards it -or the wind has no effect like in electromagnetic radio waves, not carried/deflected by wind- ? The decontamination being obviously more extensive near the initial accident site, how deep does it reach ? Is it skin deep as if paint would be scraped off, it would produce a considerable improvement, or is it deep into concrete, wood structures, soil, plants, trees, water in creeks ? What is the change expe…

I would like to talk about an instrument that has been sometimes overlooked: ESPRESSO. As most of you probably know, ESPRESSO is the only current spectrograph able to detect Earth-sized planets. I think it will be a key instrument for 2 reasons: 1- The majority of the most potentially habitable exoplanets were discovered with the radial velocity method. 2- Only 0.5 % of the Earth-like planets in the Milky Way could be detectable by using transit photometry. Do you think we will find a nearby Earth 2.0 with ESPRESSO in 2020?

I'm not entirely sure this fits under science education, however it is somewhat science related, specifically light science, and I do need to be educated. Imagine you are outside on a perfectly sunny day with a nice white piece of tagboard (because it's heavier and harder to blow away) and you hold up, for sake of example, a translucent red piece of glass between the light source, in this case the sun, and the tagboard and the sun shines through the piece of glass and creates a duplicate image onto that tagboard, the shape of which alters depending on what angle you hold the glass. What is that duplicate image called, please? I thought it was refraction, but no…

So I was thinking about cold temperatures lately, because of the early winter. I realized that for a temperature to be at absolute zero it can't gain any heat from its surroundings. But for that to be true, then we cannot create absolute zero here on earth because the earth itself will always provide some sort of heat from the surroundings (the core and such). So, then I thought that maybe a whole planet (somewhere out there) could be at absolute zero, but then wouldn't literally all of the planet have to be at that temperature? But couldn't the gases on the planet also contain heat? Including oxygen, so therefore, absolute zero can only be attained in a space with no oxy…

I think that Alpha centauri could host the closest Earth-like planet. A study shows that 22% of G and K-type stars could have Earth-like planets orbiting in the habitable zone. There are 9 Sun-like stars within 25 light-years. If we make the calculation, two of those stars could have an Earth-like planet. One of those two exoplanets could be Tau Ceti e. Which exoplanet could be the other one? 7 out of the 9 closest Sun-like stars have low metallicity. The only two stars with high metallicity are Alpha Centauri A and Delta Pavonis, but this star is suspected to be variable. What do you guys think?

Hi all. Underwater, it is not simple to discern the direction a sound comes from; perhaps with the increased propagation speed the brain is unable to 'compute' the differential arrival times to each ear; or by the external ear lobes shaping and directional capabilities in a not-air medium; or both, or other factors. What methods would be convenient to evaluate, experiment to find the incoming direction of sound waves underwater ? (~1500m/s) Would multiple microphones (6?) and timing analysis do it ? What else comes to your mind ?

Hi everyone, I am most likely the least scientifically minded person to ever have visited these forums! I'm here with a question that I hope someone more scientifically minded can answer for me. If a pair of plastic coated axial neodymium magnets are installed either side of a sheet of alloy, will the electromagnetic field from the magnets cause electrolysis on the alloy sheet? The alloy sheet will often in contact with salt water. Thanks in advance for any answers or information on this.

If the universe is unlimited yet still expanding, what is it expanding into

In a book the radius of gyration is defined as "Radius of gyration may be defined as the distance from the axis of rotation of a mass point whose mass is assumed to be equal to the mass of the whole body and whose moment of inertia is equal to the moment of inertia of the body about the axis" So can that mass point be considered as the centre of mass of the body? Acoording to me it has to be the COM. Please do correct me if i am wrong

in monatomic gases, why isn't atom rotation taken as one possible degree of freedom - that is, why energy cannot be stored in atom rotation? Is this degree of freedom non-existent or just frozen? Google finds many answers, but they seem to differ. Some say that rotation is simply not physical (whatever it means), some say that a single quantum of rotational energy is much larger than available energy at normal temperatures...