Reverse Definition and 310 Threads

  1. S

    A question about the perpendicular vector

    I tried to draw it perpendicular to the reverse, but I'm not sure if it's right. I would be very grateful if you could help me. I am in the learning process
  2. E

    Is My Samovar Really 110V or 220V? Decoding the Resistance of the Element

    Need some help please. Bought a Samovar (electric water pot) from overseas. Seller told me it is 110V compatible but the base plate not sp clearly says 110v/220V in Russian. Seller tells me that I should not use it in a 220V outlet but when plugged into a 110V it took 45 minutes to boil 8L...
  3. RealityMechanics

    Determining Reverse Mass Flow Rate Formula for Multiple Diameter Tubes

    Alright, this is more of a conceptual question than a HW question that will nonetheless help me design something. In the attached image, air is flowing through a large area tube and then a small area tube from right to left. A collaborator previously figured out the equation for measuring the...
  4. A

    I Reverse Projector: New Tech for Immersive Video Experience

    Good morning physicists, I have a small problem, having a sony projector, like all projectors I always have the usual problem of image pollution. I heard a few months ago (but now I can no longer find the link), of a new technology according to which the projector instead of projecting on the...
  5. dgsfbandeira

    I How to 'reverse' derive correct value when given MEAN + SD

    I have a scatterplot that I'm trying to extract. I found 54 values out of 55. There is one "missing" value, probably because it is overlapped and I can't actually see. I have the MEAN and Stand Dev of the 55 values. Is there a way to reverse find the one that is missing? I mean, is there a...
  6. person123

    I Shallow Water Wave Equation Simulation: Reverse Shoaling?

    I'm creating a simulation of the shallow water wave equation in MATLAB. I'm using the equations: $$\frac{\partial v}{\partial t}=-g\frac{\partial \eta}{\partial x}$$ $$\frac{\partial h}{\partial t}=-h\frac{\partial v}{\partial x}$$ Iteratively updating the velocity from neighboring heights...
  7. A

    Is there a program that can run depletion calculations in reverse?

    I was having a conversation with a coworker and this question came up: is there a program like ORIGEN (or maybe even ORIGEN) to run decay calculations in reverse? It's a relatively easy process to start with a given quantity of an isotope (e.g. U236), run it through a program such as ORIGEN...
  8. kyphysics

    Can "Secret" Food Recipe Formulas Not Be Reverse Engineered?

    You always hear about how famous big food companies have recipes locked away in vaults. They never want to give away the secret sauce so competitors can copy them. However, with all we can do with modern technology, why can't we send a Chick-Fil-A sandwich over the a lab and have them...
  9. D

    Reverse Mass Drivers: Catching Surfaces Grazing Orbiting Spacecraft

    If a mass driver could theoretically launch a vehicle then surely it could catch one too. Anyone know about articles related to mass drivers that refer to catching surfaces grazing orbiting spacecraft ?
  10. Benjamin_harsh

    Back EMF vs Reverse Currents: What's the Difference?

    Is it Back EMF, Reverse Current, Reverse Saturation current, Backfeeding? If not, tell the difference.
  11. anubhavsingh

    Reverse saturation current and leakage current in a BJT

    I have been studying Studying Donald Neamen's Electronic Circuits 4th edition and Sedra Smith's Microelectronics 7th edition for quite some time now. I have been self studying. After searching extensively on Internet as well as trying to understand from the books, I have not been able to...
  12. F

    Can current gene editing technologies reverse age related mutations?

    How can current gene editing technologies like Prime Editing can be used to reverse all age related mutations that negatively affect some type of cell like neurons?. According to this article (you need to click on the "toggle reader view" button in firefox in order to read it without registering...
  13. S

    Speed and apparent weight of person in reverse bungee jumping

    a. To find the speed, I need to find the height where the cords first become loose, which is when the cord is 25 m long. $$h=30-\sqrt{25^2 - 5^2}$$ But the teacher's working is ##h=30-\sqrt{25^2 - 4^2}## How to get 4? b. My idea is to use Newton's 2nd law so I draw free body diagram of the...
  14. Algr

    Is pronunciation reform the key to a fully phonetic alphabet?

    I was watching a video about english spelling reform where the author, as an aside, pointed out something that I thought was rather more important than anything else in the video: A fully phonetic alphabet is impossible because we don't agree on what the words are supposed to sound like. You...
  15. E

    A.C. generator -> why does the current reverse?

    why does the current reverse when the coil is at this position in A.C generator ?
  16. S

    I Paper: To catch and reverse a quantum jump in flight

    This video www.youtube.com/watch?v=j5HyMNNSGqQ and the paper it refers to https://www.nature.com/articles/s41586-019-1287-z (available also at : http://qulab.eng.yale.edu/documents/papers/zlatko_paper.pdf ) ... talks about how a quantum transition can be monitored and manipulated in real time...
  17. XXXtentacionXXX

    Can you reverse entropy without using energy?

    Can you reverse entropy without using energy?
  18. newjerseyrunner

    I How Do You Reverse a 2.5D Projection Function in Programming?

    I have this function that I need to reverse. I can't figure out how to reverse it though, I should be able to take the resulting int, put it through a function with the height value and get back distance. Normally, when I get stuck, I just ask wolfram alpha to solve it for me, but that...
  19. 256bits

    Project Drawdown - Plan to Reverse Global Warming

    Usually it is just about the nasty oil, and goodness of electricity. Of the 100 solutions Project Drawdown has listed, some would not even be considered along with the more commonly known by the public at large https://www.drawdown.org/ From cultivation of rice ( number one crop of the world )...
  20. S

    Reverse gravity-assist, using the moons of a planet

    Hello, We hear a lot about gravity-assist, which usually means using a planet like Jupiter to speed a spacecraft on its way to another destination, like Pluto. But what about using a moon of a planet as a reverse gravity-assist? For example, if you wanted to place a spacecraft in orbit...
  21. H

    I What is the value of n in Reverse Combinatorics problem?

    Not homework, just working odd numbered problems in the book. Sue has 24 each of n different colored beads. If 20 beads are selected (with repetition allowed) what is the value of n if there are 230,230 possible combinations. I view this as a problem of number of integer solutions to a linear...
  22. dvscrobe

    Engineering Reverse Current PMDC Motor Braking Using Power Electronics

    Summary: How do you determine the armature current during the braking time? For a simple permanent magnet DC motor with a known resistance and inductance in series with the armature, I would like to know how to determine the armature current if there was an electronic motor drive controlling...
  23. R

    Reverse reactions and Le Chateliers principle

    In acid-base reactions, the reaction never goes 100% toward the product, right? A reverse reaction will occur and eventually reaction toward product and reactant will reach equilibrium. In lab/industry conditions where yield is important, how does they push the reaction toward product? I am...
  24. chwala

    Reverse substitution to find the inverse of modular arithmetic

    ##132,289≡1973* 67 + 98## ##1973≡98*20+13## ##98≡13*7+7## ##13≡7*1+6## ##7≡6*1+1## now in reverse my attempt is as follows, ##1≡7-6## ## 1≡7-(13-7)## ##1≡2*7-(1973-20*132,289+1340*1973)## ##1≡2*7-(1341*1973-20*132,289## which is correct but my interest is in finding the inverse of 1973 help?
  25. A

    Are orbital sun shades to reverse climate change realistic?

    I'm referring to proposals that suggest putting large reflective surfaces at the L1 Lagrange point. I've also been thinking of something like capturing a nearby asteroid and turning it into an artificial ring at the equator or dumping lots of small infrared reflecting particles or releasing...
  26. TheQuestionGuy14

    B If the universe were played in reverse, how would it differ?

    What if the universe suddenly started playing in reverse, like playing a recording in reverse. Particles gain kinetic energy from heat and sound energy as they travel the opposite way, light retreats back into the sun etc. Would this universe differ in any way? Does anything not work if time...
  27. C

    Diode operation from reverse bias to zero bias

    Assume we have a closed diode circuit .We connect the n type region of the diode to the positive terminal of the battery.We connect the p type region of the diode to the negative terminal of the battery.The depletion layer is increased.Now we open the circuit.Why the diode returns to its zero...
  28. GabrielCoriiu

    I How to Determine N from Refraction Angles and Constants?

    I'm trying to reverse engineer refraction. So given I, R and k in the image, what is N so that sin(θ1)/sin(θ2) = k ?
  29. D

    Reverse Engineering Plastics: Is It Cost Effective?

    I would like to know if plastics can be reverse engineered or are the costs too significant .
  30. Y

    B L bracket vs reverse L bracket

    Hi all, The photo is a reverse L-shaped bracket installed on the wall, L or reverse L is of more supporting force if all things being equal? Why? Thank you very much!
  31. W

    Legacy Database Reverse Engineering and Methodology

    Hi All, Say we have a legacy database that is not well-documented and we want to reverse-engineer it. I am looking for an effective way of doing it. Only way I can think is using something like ERwin to produce a Conceptual, Logical model for the database from which we can reconstruct the...
  32. F

    Reverse the elements in a given array

    Homework Statement Write a sequence of statements to REVERSE the elements of array X1. Homework Equations - The Attempt at a Solution Here's my work : Could somebody check my answer please ?
  33. karush

    MHB 232.15.3.50 Reverse the order of integration in the following integral

    $\textsf{Reverse the order of integration in the following integral }$ \begin{align*}\displaystyle I&=\int_0^1 \int_2^{2e^x}f(x,y) \quad dy \, dx \end{align*} $\textit{From the integral we have that}$ $$0\leq x\leq 1 \quad \textit{and} \quad 2\leq y\leq 2e^x$$ $\textit{So, we get that}$...
  34. jedishrfu

    B What is Reverse Mathematics and how does it relate to traditional mathematics?

    I just found an interesting book at BN, titled Reverse Mathematics Proofs from the Inside by Prof John Stillwell. https://press.princeton.edu/titles/11143.html He mentions that it’s a growing field in mathematics where we seek to discover the right axioms to prove a theorem...
  35. J

    Residual magnetism in shunt generator reverse F1F2

    Hi, I'm not able to understand how reversing Field terminals will help build magnetic flux in dc shunt generator Have drawn diagrams below. In 1st case machine doesn't generate as the flux opposes residual flux, so I reverse F1, F2 and draw below diagram... But in second case the direction of...
  36. 1oldman2

    What can the evolution of the ribosome tell us about the origin of translation?

    https://www.newscientist.com/article/mg23631500-500-the-very-first-living-thing-is-still-alive-inside-each-one-of-us/ "We can stop <<profanity deleted>> about the origin of life," says Loren Williams, a biochemist at the Georgia Institute of Technology in Atlanta. "We can see it."
  37. D

    An idea to reverse global warming

    Elon Musk says we can terraform Mars by converting its CO2 and H2O into CH4 and O2 using solar power, the latter two compounds being quite useful. Can't we use his idea to reduce the CO2 in our atmosphere and reverse global warming?
  38. C

    Reverse a String in C - Solve Segmentation Fault

    This is what I came up with but I keep getting segmentation fault whenever I run it in linux. Not sure why. Any help would be appreciated. Thanks #include <stdio.h> #include <string.h> #include <stdlib.h> int main(int argc, char** argv) { int i, childpid; for (i = strlen(argv[1]); i >=...
  39. J

    Would a reverse wing sweep be better for speeds above Mach 2

    I am curious about a reverse wing sweep because it could be used on an aircraft for turning at high speeds at higher than Mach two.
  40. karush

    MHB 15.2.60 Reverse the order of integration

    $\textsf{Reverse the order of integration in the following integral }$ \begin{align*}\displaystyle I&=\int_0^1 \int_2^{2e^x}f(x,y) dydx \end{align*} ok tried to follow some examples but 😰 \begin{align*}\displaystyle I&=\int_0^1 \int_?^{?}f(x,y) dxdy \end{align*}
  41. Absentee

    "Regular" filtration with reverse osmosis filter?

    A nanofiltration filter has a pore size around 0.001 micron. Reverse osmosis filters have a pore size around 0.0001 micron. Additionaly, reverse osmosis occurs when a semi-permeable membrane separates solutions of different concentrations so osmotic pressure has to be applied to move water from...
  42. satominari

    Why is there reverse current in diode equation?

    When deriving diode equation, it is assumed that there's no drift. But still, in the result, we have a reverse current which is a drift... I don't get where this comes from.
  43. TMT

    Overall efficiency of cascaded reverse Carnot engine & a Rankine turbine

    Assuming a reverse Carnot engine (Heat Pump Achieve 353K after compression and 253K after evaporation) is cascaded to Rankine turbine such that heat rejection to a steam boiler and heat is collected from a thermally isolated compartment first (used as condensation by cooling) then from ambient...
  44. R

    DC motor running in reverse after repair

    Hi all, so my mercury 25 outboard starter was starting to give it up. I took it apart, and yup, the brushes were badly worn. Well, I have several generic brushes kicking around, so I simply swapped them out. Very simple operation. And yet after assembling the damn thing, it now runs backwards...
  45. Irfan Nafi

    Difference between reverse bias and forward bias for a photodiode

    I'm creating a project where the motors have to be triggered by a photodiode. A light provides a steady stream of current to the photodiode and when that incident light is scattered, the motors move. But in reverse bias a photodiode needs to have a dark environment to provide 'infinite...
  46. J

    MHB Need help to reverse engineer a problem...........................

    I hoping that someone may help me find a formula for this problem... Starting with a specific, large-sum number (ex. 5,408,286,291), find 4, three or four digit numbers that, when multiplied, will arrive at this large-sum number. It could be 3 larger numbers or 4 smaller numbers. It doesn't...
  47. mastermechanic

    Is reverse engineering ethical?

    Suppose that there are 2 companies. One of them is yours and other company publishes a product which can affect your situation in marketplace.Is it ethical to buy the product and resolve it by reverse engineering to get an idea to counterattack? It's not about producing similar technology...
  48. Nikhil N

    Design of CT with ferrite core for reverse operation of CT

    I have to couple noise into data cable(cat5) in common mode. I have done this with a CT of 50A/1A, ferrite core. What I have done is, I connected the S1 and S2 of CT to probe of my signal generator and inserted the cable through the whole of CT(ring type). I got maximum of 380mV in the cable...
  49. F

    B Does right/left spin reverse in tunneling particles?

    As I understand it, a relativistic reversal can occur in a Lorentz boost. A particle's forward angular momentum can become backward angular momentum, if the observer accelerates sufficiently. But the particle and its angular momentum are unchanged. The only change is in the observer’s frame...
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