Line Definition and 1000 Threads

  1. A

    How to calculate the 3D straight line distance between 2 GPS measurements?

    This seems like a trivial question at first, but I am struggling how to get it right. If I have 2 GPS (lat, lon, height) observations P1 and P2 taken at some height from the Earth's surface, how do I calculate the straight line distance between them? I am using the picture below to illustrate...
  2. mmaismma

    Points on either side of a line

    Summary:: The set of values of ##b## for which the origin and the point ##(1, 1)## lie on the same side of the straight line ##a^2x+aby+1=0## ##\forall~a\in\mathbb{R},~b>0##.(a) ##a\geq1## or ##a\leq-3## (b) ##a\in~(-3,~0)\cup(\frac13,~1)## (c) ##a\in~(0,~1)## (d) ##a\in~(-\infty,~0)## I tried...
  3. S

    MHB Finding lines through given point perpendicular and parallel to given line

    Hey, not sure how to translate this from my native language, I hope you understand what I mean. Write down for the line y = 2x + 3 perpendicular and parallel lines passing through the point (1; 1) equations.
  4. W

    Python Python 3 Anaconda:Syntax Error on inexistent line#

    Ok, I wrote a small program P, initially of 16 lines in Jupyter Anaconda in Python 3.7 I deleted the last 4 lines, ending up with 12 lines in P2. Now, I run P2 and I'm told there is a syntax error in (the inexistent) line 14. I restarted the kernel, nothing. I opened another notebook, pasted...
  5. R

    Line integral around a circle centered at the origin

    Hi everyone, I am confused in this question. First I solved it by noticing that the gradient of the function will be zero (without substitution the hit) I got that it's a conservative field so the integral should be zero since it's closed path. Then I solved it by the hit and convert it as any...
  6. R

    B Can someone tell me if I got this line from the Feynman lectures right?

    'Mass is found to increase with velocity, but appreciable increases require velocities near that of light. A true law is: if an object moves with a speed of less than one hundred miles a second the mass is constant to within one part in a million. ' What does 'constant to within one part in a...
  7. M

    Show that the line state is separable

    I introduced the unitary transformation ##U=U_a \otimes U_b## with ##(U_a\otimes 1):\;|s,s> \rightarrow\,\frac{1}{\sqrt{d}}\sum_t \omega^{ts}|t,s> ## und ##(1\otimes U_b):\;|s,s> \rightarrow\,\frac{1}{\sqrt{d}}\sum_t \omega^{-ts}|s,t> ## ##(\omega=e^{2\pi i/d}##) and let it act on the state in...
  8. E

    Transmission line resonator

    Hello everyone, I am studying transmission line resonators and in particular I was considering a particular case of resonator where I have an open circuited quarter wavelength transformer of high impedance terminating a regular 50 ##\Omega## line. If I look at the input impedance from the open...
  9. R

    I Why a is not equal to zero in this pair of straight line equations?

    Let say we have two line ##a_1x+b_1y+c_1=0## and ##a_2x+b_2y+c_2=0##. Then pair of straight line equation is ##a_1a_2x^2+(a_1b_2+b_1a_2)xy+b_1b_2y^2+(a_1c_2+c_1a_2)x+(b_1c_2+c_1b_2)y+c_1c_2=0## i.e ##ax^2+2hxy+by^2+2gx+2fy+c=0## Now if we take ##a_1=0##, then the first line becomes...
  10. S

    Plumbing Order of devices in the main water line?

    I have a house where water enters from the street in a 1" PEX line, which comes up from the slab inside a closet. No other permanent plumbing is yet installed. I want to install a shut-off valve, a pressure regulator, pressure valve, and a sediment filter. I'm also considering installing a...
  11. T

    Struggling to understand stretch and strength in fishing line

    I'm an angler and having extensive discussions on a fishing forum about the properties of monofilament fishing line. There are two forms: various nylons - mainly we think PA6 and PA66 - and fluorocarbon. Our experience and 'garage testing' of these lines tell us that fluorocarbon while it can...
  12. M

    Kinematics Problem: constant acceleration, motion in a line

    I've been attempting to solve this problem for three days now. I have thrown away my old attempts (like, scrumpled up into the bin), but my old attempts involved: Trying to set up simultaeneous equations relating the journeys between EH and FG to find the deceleration, but the reason why this...
  13. N

    Transistor Load line doesn't intersect characteristic curves....

    Hello, I've carried out an experiment to plot the characteristic curves (Ic vs Vce) for a BC108 transistor and then attempted to find where the load-line intersects those curves. Below are my results: ...as you can see, the load-line doesn't intersect the characteristic curves at all...
  14. S

    Periodic images of dipole line charge followed by a vacuum space

    Can I sum up the potential due to all positive line charges and all negative line charges separately, with the boundary condition being at the edge of my unit cell, the potential should be the same and inside the metal there is a contant potential?
  15. A

    Equations of motion of a point sliding on a line of arbitrary shape

    Hi! First of all, mention that this is not a "homework" problem in the sense that no teacher ever gave it to me or that I have the obligation to do it. It is a question that came to mind when repasing the theory done in class and though interesting. I still post it here because I suppose that...
  16. E

    Line charge inside a conducting sphere?

  17. Jrogers201

    Newton's second law along a line

    As I mentioned I am self tutoring myself on a subject I studied 20 years ago. I'm sure I can answer all the questions apart from question (iii). I think I'm supposed to use a simultaneous equation. But I need to answer question (iii) to answer the rest. Any help please?
  18. N

    MHB Motion along a straight line by a car

    [FONT=Century Gothic]Part B of the following problem seems to be fairly straightforward, but I can't seem to understand it properly. I might be overthinking the problem entirely. Would anyone be willing to help?
  19. neilparker62

    Insights Revisiting The Deuterium Lyman Alpha Line Experiment

    [url="https://www.physicsforums.com/insights/the-deuterium-lyman-alpha-line/"]Continue reading...
  20. T

    I Projectile angle (straight line) between 2 planets

    I have a planetary system with planets orbitting a central star (circular orbits). I want to shoot a projectile P in a straight line from planet A to B and need to calculate the angle or vector to shoot the projectile P. I know the straight line of the projectile is physically not correct, but...
  21. R

    Find the Slope of a Line: 4:2=2

    Homework Statement: Find a slope of line? Homework Equations: The slope of a.line is 4:2=2 Can someone tell me if is right Thanks
  22. tinakaran26

    Direct steam injection into cooling water line at pump suction

    Currently there is an operation scenario at one of our plant which directly injecting steam into cooling water line at pump suction in order to generate hot water at 60 deg C for circulation, by doing this its generate vapor at pump suction and lead to cavitation which ultimately damage pump and...
  23. lfdahl

    MHB Volume of the solid obtained by rotating R around the line y=x

    Let $R$ be the region $\left\{(x, y) : 0 \leq x \leq 1, 3^x − x − 1 \leq y \leq x\right\}$. Find the volume of the solid obtained by rotating $R$ around the line $y = x$.
  24. Wrichik Basu

    MATLAB Forcing the best fit line to pass through a certain point (Octave)

    I have the following code in Octave: h = [29.3 25.3 19.7 16.0 10.9]; v = [0.53 0.47 0.37 0.29 0.21]; plot(h,v,'obk') hold on p = polyfit(h,v,1); y = polyval(p,h); plot(h,y,'-bk') And I get a good graph: I can extrapolate the best fit line using the following code: x = -1:0.01:11; >> y =...
  25. karush

    MHB -3 circles centers on line segment PQ

    it was done by simple observation typos maybe,,,, Also, posted on MeWe and Linkedin
  26. Vital

    I Least squares line - understanding formulas

    Hello. I have listened to a great lecture, which gave helpful intuitive insight into correlation and regression (basic stuff). But there are formulas, which I cannot grasp intuitively and don't know their origin. To remember them I would like to understand what's happening in each part of the...
  27. Yalanhar

    Calculate the electric field due to a line of charge of finite length

    Homework Statement: A thin rod of length L and charge Q is uniformly charged, so it has a linear charge density ##\lambda =q/l## Find the electric field at point where is an arbitrarily positioned point. Homework Equations: ##dE=\frac{Kdq}{r^2}## A thin rod of length L and charge Q is...
  28. Arman777

    I Fınding the position of a point on the line

    Let us suppose we have a line ##l_1 = ax + by + c = 0## and we have a point P, ##P(x_p, y_p)## that is outside of this line. If we draw a perpendicular line from point ##P## to a point on the ##l_1##. What would be the coordinates of this point ? I know there are many ways to do it. But I am...
  29. F

    I Do action force and reaction force lie on same line?

    Do action force and reaction force(Newton's third law) lie on same line?If not then the angular momentum will be violated.I don't know why a cat falling can rotate itself before contact land if the conservative law of angular momentum not be violated?
  30. P

    MHB Inverse Functions: Reflection of f(x) & g(x) Logic

    Can anyone explain the logic behind the answer? Taken from HiSet free practice test
  31. karush

    MHB 210 AP Calculus Exam problem tangent line to curve

    Find the slope of the tangent line to the graph of $$f(x)=-x^2+4\sqrt{x}$$ at $x=4$ (A) $8-$ (B) $-10$ (C) $-9$ (D) $-5$ (E) $-7$
  32. L

    Charge distribution on a power line

    I was trying to calculate the EMFs from power lines, just to see how they correspond to transmission line right of ways, and got a little stuck calculating the electrostatic E-field (-∇V) from power lines. I know it is dependent on the charge distribution on the power line, which is in turn...
  33. M

    A How can a zipper MRI artifact be limited to a single line?

    he so-called [herringbone or spike MRI artifact][1] on a given example could be traced to a specific point(s) in Fourier space ("k-space"). The idea is that during the acquisition of the image, a certain RF wave emitted by the patient (providing the info about diseased or normal anatomy) had...
  34. neilparker62

    Insights Calculating the Balmer Alpha Line: Atomic Hydrogen

    Continue reading...
  35. Y

    MHB How Can I Find the Equation of the Dotted Tangent Line of a Circle?

    Dear all, Attached is a picture of a circle. The lower tangent line is y=0.5x. The center of the circle is M(4,7) while the point A is (3,6). I found the equation of the circle, it is: $(x-4)^{2}+(y-7)^{2}=20$ and I wish to find the dotted tangent line. I know that it is parallel to the...
  36. N

    Explain this line "thread& operator = (const thread&) = delete;"

    here delete, thread, and const are obviously keywords, I saw this when the system libraries threw a breakpoint, not my code, I'm new at this and that line of code makes very little sense to me, afaik, (const thread&) should be a conversion operator, how can you set an operator to a statement...
  37. saxman2u

    Fluid Mechanics-head loss/GPM change adding 2nd line for pumping

    I have a rainwater collection system in Austin, TX, where we have to pump water to our main 30,000 gallon tank. The system works great. My question is, our 3 HP pump pumps about 85 gallons per minute. The length of the 2"pump line is about 300 ft, elevation change is about 50 feet higher...
  38. S

    Finding line of intersection of given plane and xz-plane. Please help

    Sorry for the really messy work I know I have a problem. The other questions that the problem asked before the one I need help with are as follows: Find the intercepts and sketch the plane. Find the distance between the plane and the point (1,2,3) Find the angle between the plane and the xz...
  39. S

    MHB Does a Line Intersect a Polygon?

    Hello, I'm wondering if anyone has a formula for determining whether a line intersects a polygon. I would define the line with a starting latitude/longitude and ending latitude/longitude, and I would define the polygon with a series of latitude/longitude coordinates. Many thanks in advance...
  40. A

    Motion Along a Straight Line: Calculate velocity of a stream

    Not sure how to go about it
  41. M

    Calculate the zero-sequence line impedance

    Hi. I want to calculate sequence line impedance of transmission line. But i can't find any parameter of Z1 and Z0 of transmission line in simulink. It's only have parameter about number of phase, frequency, R1/R0, L1/L0, C1/C0 and line length. Can i calculate sequence line impedance from these...
  42. bottle_shadow

    I Line integral for work done by gravity

    Dear Physics Forums people, My problem lies in understanding how the following line integral, which represents work done by the gravitational force, was calculated Specifically, in the integral after the 2nd = sign, they implicitly used \hat{r}\cdot d\vec{s} = dr I wish to understand what...
  43. M

    Electrostatics: Understanding this "Work Done" Line Integral Question

    I have a quick question about the work done concept here, especially the line integral part of it. So I understand the fact that the work done from getting from point A to B is: \int_{a}^{b} \vec F \cdot d\vec r . However, within the context of electric fields, when we define electrostatic...
  44. John FD

    Transmission Line , OPGW Stringing

    Hi, any of you guys have experience paying out conductors leaving the OPGW later on? any idea or procedures needed so that during OPGW paying out stage later on it will not be damaged by the existing conductors. Mentor Note -- Adding link to information about OPGW...
  45. OmCheeto

    New Deccan Trap turns out to be downed power line

    A link to this video popped up on my Twitter feed this morning: link The person who posted it asked for guesses as to what it was. I guessed; "Baby Deccan Traps?". She said "No." Then she posted the explanation: Maharashtra: Panic of volcanic lava trigerred after Beed locals witness rocks...
  46. M

    MHB Extrapolation and interpolation in line search optimization

    hi can you tell me these equations: A = 6*(f2-f3)/z3+3*(d2+d3); % cubic fit B = 3*(f3-f2)-z3*(d3+2*d2); z2 = (sqrt(B*B-A*d2*z3*z3)-B)/A; % numerical error in MATLAB fmincg.m...
  47. R

    A straight line in the complex plane

    sz+tz*+r=0=say w so w* = s*z* + t*z + r*=0 Now , w+w* = (s+t*)z + (t+s*)z* + r+r* = 0 = p*z + pz* + k = 0...eq(1) ( k is a constant or twice real part of w) which is in complex straight line equation form i.e ab* + a*b + c = 0 ( a,b are complex number and c a real number. Now, again...
  48. K

    Energy density due to infinite uniform line charges

    Let ##(x_1,y_1)## and ##(x_2,y_2)## be the point where the rods intersect the ##x,y## plane. I know that on any given point there will be the superpositions of ##E_1=\frac{2\lambda}{4\pi \epsilon_0}\frac{1}{(x-x_1)^2+(y-y_1)^2}\hat{r}_1## and ##E_2=\frac{2\lambda}{4\pi...
  49. E

    Line voltage in 3 phase as single sine wave

    Howdy all. The typical image of a three phase electrical system involves 3 sine waves, phase shifted 120 degrees. These sine waves each, individually, represent the 'phase voltage,' which is to a common neutral in a wye configuration. In this wye configuration the line to line voltage is...
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