Linear Definition and 1000 Threads

  1. H

    Finding linear acceleration of a spool and cable

    My angular acceleration is wrong but all I had done was torque which was 110 NM / I = 930 kg-m^2 and calculated 0.118 rad/s^2. But because this is wrong I am stuck and I have no idea how to find angular velocity to plug into the equation to find linear acceleration.
  2. B

    : Calculation of Linear Bearing (Carriage) Load

    Hi Guys, please please assist me! I need to pick for a project at my work linear carriages which should work at this configuration : As you can see, there is a piston which moves the plate on 4 bearings from the side (yes, I know, not the best configuration, but that's what we have given the...
  3. P

    Linear algebra problem with a probable typo

    Well, my guess is that there is something wrong with the factors chosen, because ##\left\Vert \left(0,1,0\right)\right\Vert =1## and \begin{align} \left\Vert F\left(0,1,0\right)\right\Vert &=\left\Vert...
  4. A

    Help with random variable linear estimation

    Hi all, I have a problem on linear estimation that I would like help on. This is related to Wiener filtering. Problem: I attempted part (a), but not too sure on the answer. As for unconstrained case in part (b), I don't know how to find the autocorrelation function, I applied the definition...
  5. F

    I Linear Models vs Nonlinear Models

    Hello, Models can be linear and nonlinear and I just learned that a "linear model" is not just a model where the dependent variable ##Y## is connected to independent variables ##X## raised to the 1st power... The model is called "linear" because the coefficients/parameters are not raised to...
  6. V

    Satellite mechanics: linear and rotational momentum

    [This is a continuation of OP's thread here: https://www.physicsforums.com/threads/satellite-mechanics-linear-and-rotational-momentum.1046963/ ] satellite mechanics: linear and rotational momentum I'm trying to better understand classical mechanics, and came up with a question: Say we have a...
  7. V

    I Satellite mechanics: linear and rotational momentum

    satellite mechanics: linear and rotational momentum I'm trying to better understand classical mechanics, and came up with a question: Say we have a squared satellite weighting 100kg, 1 meter on each side. it has a thruster on it's side, shown in picture thruster quickly ejects 100g of propellant...
  8. A

    Linear moving switch, decade counter, chaser

    I need a row of switches, about 30 to be exact and the idea I need is to have a "moving OFF position" much the same way a "LED chaser" works where you have a moving ON position. Only unlike in a LED chaser where one diode comes ON at any given time and the positions changes continually to...
  9. H

    I Second order non-homogeneous linear ordinary differential equation

    I shall not begin with expressing my annoyance at the perfect equality between the number of people studying ODE and the numbers of ways of solving the Second Order Non-homogeneous Linear Ordinary Differential Equation (I'm a little doubtful about the correct syntactical position of 'linear')...
  10. alpha

    Python Solving Linear Programming problems in python PulP

    Okay so far I have come up with the following: The objective function is: 30LADA + 40LAHO + 50SADA + 40SAHO + 110DANY + 125DACH + 105HONY + 115HOCH (to read this please see the table above as I have just used the first two letters of each except NY which I have represented by NY). In these I...
  11. alpha

    Optimizing Constraints for Linear Programming Problem

    So far I have figured out the following: maximize 0.02x1 + 0.01x2 +0.06x3 + 0.07x4 subject to: xi <= 200,000 xi >= 24,000 x3 <= x2 +x4 x1 >= x3 But when I try to solve this in solver, I get an error which means my contraints must be wrong. Any suggestions on what constaints to put?
  12. Wrichik Basu

    GitHub: How do I merge a PR but maintain linear history + signed commit

    Suppose, for a certain a repo, I create a branch protection rule for the main branch with the following: Require pull request before merging. This means that each feature or bugfix must be on separate branches, which will be later merged with main. Maintain linear history of the main branch...
  13. M

    Solve the simultaneous linear congruences

    Consider the following set of simultaneous linear congruences: ## 3x\equiv 2\pmod {5}, 3x\equiv 4\pmod {7}, 3x\equiv 6\pmod {11} ##. Observe that \begin{align*} &3x\equiv 2\pmod {5}\implies 6x\equiv 4\pmod {5}\implies x\equiv 4\pmod {5}\\ &3x\equiv 4\pmod {7}\implies 15x\equiv 20\pmod...
  14. M

    I Systematic uncertainties in linear fit

    Hello! I have some data points ##(x,y)##, with some uncertainties on y that are statistical ##dy_1## and some systematic ##dy_2##. I want to fit this data using a linear function. How exactly should I deal with the different types of uncertainties? Can I just add them in quadrature and perform...
  15. J

    Linear operator in 2x2 complex vector space

    Let C2x2 be the complex vector space of 2x2 matrices with complex entries. Let and let T be the linear operator onC2x2 defined by T(A) = BA. What is the rank of T? Can you describe T2? ____________________________________________________________ An ordered basis for C2x2 is: I don't...
  16. J

    Linear Transformation from R3 to R3

    "There is a linear transformation T from R3 to R3 such that T (1, 0, 0) = (1,0,−1), T(0,1,0) = (1,0,−1) and T(0,0,1) = (1,2,2)" - why is this the case? Thank you.
  17. murshid_islam

    What would be a good book for learning Linear Algebra by myself?

    Summary: What would be a good book for learning Linear Algebra by myself in my situation (which is explained in my post below)? I did an undergraduate Linear Algebra course about 18 years ago. The textbook we used was Howard Anton’s “Elementary Linear Algebra”. The problem is that I never...
  18. guyvsdcsniper

    How Do You Convert Linear Operators to Dirac Notation?

    I am trying to convert the attached picture into dirac notation. I find the LHS simple, as it is just <ψ,aφ>=<ψIaIφ> The RHS gives me trouble as I am interpreting it as <a†ψ,φ>=<ψIa†Iφ> but if I conjugate that I get <φIaIψ>* which is not equiv to the LHS. *Was going to type in LaTex but I...
  19. E

    B Attempt to solve this system of three linear equations

    The point (1, 5) is on the curve: y=ax^2+bx+c. This point gives the linear equation: 5 = a + b + c. A second point on the curve, (2, 10) gives the linear equation 10=4a+2b+c. A student called Erika thinks that the point (2, 19) is also on the curve. 5 = a + b + c. 10=4a+2b+c 19=4a+2b+c the...
  20. Graham87

    Intro to quantum mechanics - Spin and linear algebra

    So this expression is apparently in Sz basis? How can you see that? How would it look in Sy basis for example? The solution is following. They are putting Sz as a basis, bur how do you know that Sz is the basis here? Thanks
  21. M

    Obtain the eight incongruent solutions of the linear congruence

    Consider the linear congruence ## 3x+4y\equiv 5\pmod {8} ##. Then ## 3x\equiv 5-4y\pmod {8} ##. Note that ## gcd(3, 8)=1 ## and ## 1\mid (5-4y) ##. Since ## 3^{-1}\equiv 3\pmod {8} ##, it follows that ## x\equiv 15-12y\pmod {8}\equiv 7+4y\pmod {8} ##. Thus ## {(x, y)=(7+4y, y)\pmod {8}\mid 0\leq...
  22. TGV320

    Courses Linear Algebra Self-Study: Textbook & Quantum Mechanics

    Hello, I have been looking for textbooks for self-studying linear algebra, which seems to be quite an important course. I have read that in order to study quantum mechanics well, one must have a very good command of linear algebra. Some textbooks in my country are quite bad and only teach...
  23. P

    Absorption coefficient and Linear Optical Susceptibility

    ##\alpha## is considered to be the absorption coefficient for a beam of light of maximum intensity ##I_0##. It's related to the complex part of the refractive index as we have shown above. Now, I have a doubt. Should I solve for ##k## from the quadratic equation in terms of the linear optical...
  24. chwala

    Solve the following linear system

    Find the problem below with the solution indicated; The text approach is much clear to me... My way of tackling the problem is as follows; using echelon form (row reduction method) \begin{bmatrix} 1 & 1 & 2 & -5 &3\\ 2 & 5 & -1 & -9&-3 \\ 2 & 1 & -1 & 3&-11\\ 1& -3 & 2 & 7&-5...
  25. T

    What are the two different senses of since and how are they used?

    Summary: Hello! I'm an high school student and i want to study more math but I'm not sure where to start. Should i first study linear algebra or calculus? Hello! I'm an high school student and i want to study more math but I'm not sure where to start. Should i first study linear algebra or...
  26. M

    A Piecewise linear interpolation with uncertainties

    Hello! I have a function ##y = f(x_1,x_2)##, and I would like to do a piecewise linear interpolation. However, both the dependent (##y##) and independent variables (##x_1, x_2##) have uncertainties associated to them (the uncertainty is the same for a given variable i.e. all ##x_1## measurements...
  27. C

    I Summing linear momentum in circular rotation

    Hello everyone! I was wondering why can't we take a rotating body and see the linear movement that each particle moves to find the 'total linear momentum,' I imagine this quantity would be conserved, and furthermore couldn't you write the total linear momentum as a function of angular velocity...
  28. Ahmed1029

    How Does Equation 4.39 Apply to Dipole Moments in Griffith's Problem 4.37?

    I tried to solve it for some time and then looked at the solution manual, which got me completely lost. Those are the first lines of the solution : I'm not so sure how equation 4.39: makes him conclude that the same relation holds for dipole moments. My second concern is that I'm not sure how...
  29. A

    Effects of brownouts and power spikes on linear power supplies

    What are the effects of brownouts and power spikes on linear power supplies in particular; e.g., a linear power supply that provides 24 V to an inductive angle encoder? Thanks for any information you could provide.
  30. B

    I Uncertainties from linear interpolation

    Hello! I have a function of several variables (for this questions I assume it is only 2 variables), ##y = f(x_1,x_2)##. I want to learn this function using simulated data (i.e. generated triplets ##(x_1,x_2,y)##) and then use that function to get ##y## from measured ##(x_1,x_2)##. There is no...
  31. MidgetDwarf

    Analysis Book needed for Applied Linear Analysis Course

    The course description is as follows: Description Function spaces, convergence, inner product, bounded linear operators, integral operators and integral equations, adjoint operators, expansion in eigenfunctions, resolvent, kernel The instructor is on sabbatical, until the start of the class...
  32. Salmone

    I Linear independence of three vectors

    If I've got three vectors ##\vec{a}##, ##\vec{b}## and ##\vec{c}## and ##\vec{a}##, ##\vec{b}## are linearly independent and ##\vec{c}## is linearly independent from ##\vec{a}##, is ##\vec{c}## also linearly independent from ##\vec{b}##?
  33. R

    I How to account for linear momentum in a collision?

    Suppose a bar is fixed to an axle at one one so that it can pivot. The bar is initially motionless, but is set rotating about it's axle when impacted by a ball. (The ball does not strike the bar at it's pivot point.) Suppose the collision is such that the bar is set rotating and the ball is...
  34. Salmone

    I Linear combination of states with Pauli's principle

    If I have two identical particles of ##1/2## spin, for Pauli's exclusion principle all physical states must be antysimmetrical under the exchange of the two particles, so ##\hat{\Pi}|\alpha\rangle=-|\alpha\rangle##. Now, let's say for example this state ##\alpha## is an Hamiltonian eigenfunction...
  35. J

    Max linear speed of propeller tip in water

    Homework Statement:: project not homework Relevant Equations:: vectors Hi,I am trying to determine the maximum linear velocity of a propeller tip when subject to flowing water with velocity ##\vec V##. For simplicity, I will assume that rotational inertial is negligible. The drawing below...
  36. shivajikobardan

    Comp Sci Can't we use linear regression for classification/prediction?

    they say that linear regression is used to predict numerical/continuous values whereas logistic regression is used to predict categorical value. but i think we can predict yes/no from linear regression as well Just say that for x>some value, y=0 otherwise, y=1. What am I missing? What is its...
  37. isaacdl

    A Proving $g(u,v)≠0$ with Linear Independence

    I'm trying to prove that there exist always a vector w whose contraction with a lightlike vector u (g(u,u)=0) it's always different from zero: $g(u,v)≠0$I know how to do this with coordinates, but in a free cordinate scheme I'm totally lost. Any help? PD: Both vectors are linearly independent.
  38. M

    A Linear combination of data with uncertainty

    Hello! I have 2 measured data points (they are measurements of different observable, not 2 measurement of the same observable), with quite different errors, say ##x_1 = 100 \pm 1## and ##x_2 = 94 \pm 10##. I want to compute the value (and associated uncertainty) of a linear combination of them...
  39. M

    Engineering First order non linear to state space equations

    How to represent this system in state space form? where: $$ x' = Ax + Bu \text{ and }y = Cx + Du$$ I am trying to create a state space model based on these equations on simulink, need to find A, B, C and D but like I mentioned, i cannot find the solution when the differentials are not of...
  40. chwala

    Solve the problem involving linear programming

    Find question and solution here; The initial steps were a bit confusing to me...i decided to use hours instead of minutes ...only then did it become more clear to me. See my graph, Ok i follow that the function would be optimised at ##x=45## and ##y=6.25## ...now to my question...we...
  41. H

    Finding the angle at the apex of a rhomb with incoming linear wave

    Hi, Since I'm dealing with a rhombus, the angle at the bottom(A) and top(A) are the same. Thus, I only have to find the angle at the bottom since the incoming beam is already perpendicular to the side of the rhombus. Since the incoming beam is perpendicular to the side ##\theta_I = \theta_T =...
  42. L

    A Propagation modes and linear systems

    In the book "Fundamentals of photonics", the authors defined waveguide modes using the notion of linear systems, where they said: "Every linear system is characterized by special inputs that are invariant to the system, i.e., inputs that are not altered (except for a multiplicative constant)...
  43. H

    I Understanding the Expression for a Linear EM Wave Transmission?

    Hi, I have an expression in my textbook that I don't really understand. I have 2 questions regarding this expression for a linear EM wave## \tilde{\vec{E_{0i}}} = (E_{0x} \hat{x} \pm E_{0y} \hat{y}) e^{i(kz- \omega t)}## ## \tilde{\vec{E_{0t}}} = (\sum_j E_{oij} e_{pj}) \hat{e_p} ## ##...
  44. ChichoRD

    Creating an Enemy with 2D Linear Movement: Calculating Projectile Angle

    Hi, I am a game developer and recently found myself in a situation where I wanted to create an enemy that shoots at you given a set of variables. The game takes place in a top down view so there is no need for gravity acceleration, just 2d linear constant movement. The question to answer is...
  45. G

    Force on a particle of a linear charge distribution

    Hello! I am trying to solve this exercise of the electric field, but it comes out changed sign and I don't know why. Statement: On a straight line of length ##L=60\, \textrm{cm}## a charge ##Q=3,0\, \mu \textrm{C}## is uniformly distributed. Calculate the force this linear distribution makes...
  46. S

    Quick-adjusting linear actuator?

    I am making a project which requires a linear actuator which can be adjusted manually, in a similar manner to those Vices which have the ratchet lever, allowing you to manually push the vice in or pull it out rather than winding it in and out. I'd like the same principle but on a linear actuator...
  47. F

    Relating Linear and Angular Kinematics

    a) We use the definition of linear speed in terms of angular speed: v = r*omega omega_f = v/r = (1.25 m/s)/(0.025 m) = 50 rad/s omega_0 = v/r = (1.25 m/s)/(0.025 m) = 21.55 rad/s b) We use the definition of linear speed: v = d/t d = vt = (1.25m/s)(74 min)(60 s/1 min) = 5.55 km c) We use the...
  48. G

    B A moving magnet in a linear electric field

    If a electrically charged mass travels thru a magnetic(m) field, it will accelerate at right angles to its velocity and the m-field. Under some conditions like this the charged mass will travel in a circular loop due to this magnetic force acceleration. This info is all over the internet. e.g...
  49. H

    MATLAB Modelling a Heat Pump with Linear Compressor using MATLAB Simulink

    Hello, I am a final year mechanical engineering student designing a heat pump with a linear compressor for an electric vehicle and have decided to model this using Simulink, I would love some help on the governing equations/formulas needed for each component of the heat pump as well as guidance...
  50. A

    Engineering Signals & Systems with Linear Algebra

    Hello everyone, I would like to get some help with the above problem on signals and linear projections. Is my approach reasonable? If it is incorrect, please help. Thanks! My approach is that s3(t) ad s4(t) are both linear combinations of s1(t) and s2(t), so we need an orthonormal basis for the...
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