2d Definition and 1000 Threads

  1. J

    Two boxes with same initial velocity on a 2d track but one is at top of a hill

    I'm trying to understand a problem someone gave me recently. there is a frictionless track that initially starts flat then there is an incline of 20 degrees then it levels out again at the bottom of the incline. you have two masses, 1 is .4 kg and is located at the top of the hill and has an...
  2. G

    Eigenvectors of a 2D hermitian operator (general form)

    Homework Statement Calculate the eigenvectors and eigenvalues of the two-dimensional matrix representation of the Hermitean operator \hat{O} given by |v_k'>\left(O|v_k>= {{O_11,O_12},{O_21,O_22}} where all Oij are real. What does Hermiticity imply for the o - diagonal elements O12...
  3. P

    Football 2D Motion: Time in Air

    A football is kicked at ground level with a speed of 19.8 m/s at an angle of 33.8° to the horizontal. How much later does it hit the ground?
  4. 5

    2D Kinematics - Projectile Motion Question

    Homework Statement A daredevil is shot out of a cannon at 33.7◦ to the horizontal with an initial speed of 25.5 m/s. A net is positioned at a horizontal distance of 43.7 m from the cannon from which the daredevil is shot. The acceleration of gravity is 9.81 m/s^2 At what height above the...
  5. H

    2D Projectile Motion problem, is there a better solution?

    Homework Statement Romeo is chucking pebbles gently up to Juliet's window and he wants the pebbles to hit the window with only a horizontal component of velocity. He is standing at the edge of a rose garden 8.0 m below her window and 9.0 m from the base of the wall. How fast are the pebbles...
  6. S

    What is the electrical potential energy of a triangular charge configuration?

    Homework Statement Derive and simplify an expression for the electrical potential energy of the charge configuration. It's an equilateral triangle with charges +q, -q and +q. Homework Equations Ep=Kq2/r The Attempt at a Solution I know how to do this with squares (it's basically...
  7. A

    MATLAB 2D plot of a function WITH MATLAB

    My function is; y(x,s)= 1-(cos[(s-1)arctan(x)]*gamma(s-1))/(1+x^2)^(s-1)/2 varible x will have range from 0 to 10. At one time the s value will be constant e.g. s = 3 but I want to change s for different values( is there any commands in MATLAB that will allow me to do this ?). I tried many...
  8. P

    C: 2D arrays with structs and pointers

    I wanted to make a variant on having a player just walking around a small 2d map. Instead of having 2 variables to store the current x and y values of the player position in a certain array, I want to make a 2d array that is filled with NULL pointers. Then the player would be represented as a...
  9. J

    Drawing 2D Velocity Structures?

    Drawing 2D Velocity Structures? Homework Statement I need some help in drawing structures such as velocity of the plane relative to the air, velocity of the plane relative to the ground, and velocity of the air relative to the ground. Please give me some tips on how to drawing these, thanks!
  10. Z

    Finding Tangent and Perpendicular Vectors on a 2D Graph

    Homework Statement f (x) = e^(3x) + sin(2x) + 3x +1 (a) Find a vector V that is tangent to the graph of y = f(x) at the point ( 0, 2). (b) Find a vector N that is perpendicular to the graph of y = f(x) at the point ( 0, 2). 2. The attempt at a solution The first step I took is to...
  11. T

    2D Conservation of Momentum Question

    A steel ball of mass moving with a velocity of 2.0 m/s [E], strikes a 1.2 kg copper ball initially moving 1.0m/s [W]. The collision is a glancing one, causing the steel ball to have a velocity of 1.5 m/s [W 30 degrees N] and the copper to move in the direction [E 47 degrees S]. Is the collision...
  12. S

    2D Kinematics - Projectile Motion

    Homework Statement A koala throws a eucalyptus branch. It goes 1.5 meters. If it left at 43 degrees, what velocity did the branch have when it left the koala's paw? The answer must be in vector form (m/s @ degrees). Needed: initial velocity Known: x-displacement = 1.5m x-acceleration =...
  13. S

    How to Plot a 2D band structure?

    Dear forum people, I just learned how to get a tight-binding dispersion for graphene: E = +- \sqrt{1+4\cos((\sqrt{3}a/2) k_x)\cos((a/2) k_y)+4\cos^2((a/2) k_y)} But i can not figure out how can I plot that. I want to plot that in the following path: K \rightarrow \Gamma \rightarrow M...
  14. T

    How to Determine Forces in a 2D Truss Using the Joint Method?

    Homework Statement Determine force of each member using joint method Homework Equations T = F x D The Attempt at a Solution Answers are: Fab 2465 T Fbd 1200 T Fbc 1375 C Fdc 750 C Fde 860 T (This one is what I tried) Fce 649 C Fac 1922 C Thanks.
  15. X

    2D Momentum of automobile collision Problem

    Need help with two 2D momentum questions. Q1: Two automobiles collide at an intersection. One car of mass 1.4x103 kg is traveling at 45km/h [south]; the other car of mass 1.3x103 ks is traveling at 39 km/h [east]. If the cars have a completely inelastic collision, what is their velocity after...
  16. M

    What Are the Final Velocities of Ball A and Ball B After Collision?

    Homework Statement The drawing shows a collision between two balls. Ball A has a mass of .030kg and is moving along the x-axis with a velocity of +5.5 m/s. It makes a collision with ball B, which has a mass of .055kg and is initially at rest. The collision is not head-on. After the collision...
  17. T

    Net Force: Identifying and Summing Forces for 2D Surfaces at Angles

    See attachement for required information. Please and thank you!
  18. D

    Throwing a ball in a 2D projectile motion and lands on an inclined plane

    Attached is an image showing the problem. Supposed the β, θ, and √o are given. How do we get the distance from the initial position of the ball to the final position on the inclined plane?
  19. T

    2D construction made of square blocks. Breaking by gravity

    Hi, Imagine: a computer program like 2D Lego with only 1 type of block (a small square one) with which you can create constructions. Blocks can be placed on an invisible grid. There is gravity, and boxes can't fly, so you need to build any construction from the ground up. Boxes are always...
  20. C

    How to model flight of simple parachute in 2D?

    How would one model flight of simple parachute in 2D? For example a formula(s) that would effectively allow you to map the parachute's position/velocity/glideAngle over time. I'm imaging dropping the parachute (consider in 2D only to make easier) and then it will be affected by forces...
  21. Y

    Calculating 2D Dispersion Relation with Different Atom Types

    I have derived 2D dispersion relation which has the same atoms. But I also need to calculate this 2D dispersion relation with two different atoms. One atom is located at the center and the other type of atoms surrounds this atom. But I am not sure how ı should calculate it because only...
  22. O

    Projecting 3D point to 2D / view-point

    Recently I was assigned to implement a procedure involving "3D projections" to "2D space". Supposing that 3D data is stored in a n x 3 matrix X, the final step involves Y=XP, where P is a 3x2 matrix. However, I would need to be sure about the actual meaning of the word "projection" to 2D. In my...
  23. E

    Basic 2d DFT - interpreting the coefficients

    Thanks for any help! I'm trying to understand the coefficients of a 2d DFT. say we've got this matrix, f(a,b) \left( \begin{array}{ccc} 9 & 1 & 9 \\ 9 & 1 & 9 \\ 9 & 1 & 9 \end{array} \right) I used wolfram alpha's function, Fourier{f(a,b)} and the transform comes back as \left(...
  24. fluidistic

    Laplace equation in 2d problem, Dirichlet problem

    Homework Statement Consider a circle of radius a whose center is in (0,0). Let (r, \phi) be the polar coordinates and (x,y) the corresponding rectangular coordinates of the plane. Calculate the solution to Dirichlet problem (interior) for Laplace equation \nabla ^2 u =0 with the following...
  25. L

    Struggling with 2D and Projectile Motion for Your Test?

    Can someone give me some two dimensional and projectile motion questions in this thread to work on? I've got a test coming up, and I'm still not 100% with the topics. If you can help-please do so! We all know how it feels to be stressed, cmon people! :smile:
  26. C

    Find Software to Automate Recognition of 2D Graphs

    Does anyone know if there is a software program that I can find/buy somewhere that can recognize an image of a curve and generate a 2D Cartesian equation for it? In my line of work I am constantly referencing these regular 2d graphs (power vs resistance graphs for thermoelectric modules)...
  27. R

    How to convert 3d co ords to 2d orthographic?

    I'm still looking into this prior to my older thread and someone has told me of a method that I have quoted below; " All measurements are assuming that the pixel width/height is one) Let fov = the field of view, you can decide how much field of view your user will have from the target...
  28. Z

    Determining Ground State Configuration in 2D Square Well with Aufbau Process

    Homework Statement use the Aufbau process to determine the ground state electronic configuration for the 2D sqare well if it contains 4 electrons. what is the multiplicity of the ground state electronic configuration? what is the energy of this 2 D 4 electrons system? and is the system...
  29. C

    2D Kinematics Problem w/ Coefficient of Friction?

    I'm really lost on how to do this physics problem because I don't really understand all the components of the problem: A 7.25 kg block is sliding at 5.45m/s on a frictionless lab bench which is 8.6m high. The block hits a 1m "rough patch" before sliding off of the lab bench, and then lands...
  30. J

    2D Kinematics questions -been stuck fo hours on it

    Homework Statement Okay so here is the problem: A golf ball is struck and leaves the ground at 96 m/s on a 60 angle. Determine the velocity of the ball 2 seconds after it was struck. I have the answer provided, which is 32.6 m/s at 45° above the horizon. Homework Equations Obviously I...
  31. P

    Bullet in Block- 2D Projectiles w/ Motion

    Homework Statement A(n) 9 g bullet is fired into a 396 g block that is initially at rest at the edge of a frictionless table of height 0.9 m. The bullet remains in the block, and after impact the block lands 2.3 m from the bottom of the table. The acceleration of gravity is 9.8 m/s. Homework...
  32. V

    Glancing Collisions In 2D, help simplifying

    Homework Statement We are only given variables in this problem, that is: m1 travels at V, collides with 2m which is at rest results in m going off at 45° at V1 2m also goes off at 45° down at V2 Calculate V1 and V2 in terms of V Homework Equations Ʃρx-initial=Ʃρx-final...
  33. M

    2D Motion Finding the resultant using components

    Homework Statement A person walks 20m [N20(degrees)E], then 120m [N50(degrees)W], then 150m[W], and finally 30m [S75(degrees)E]. Find the person's final displacement. Homework Equations Is my solution correct? The textbook answers are 230m[N23(degrees)W] What did I do incorrect...
  34. P

    Creating 2D Maps: Practical Approaches and Limitations for 2D Creatures

    Suppose we were completely two-dimensional creatures, two dimensions plus time. How would we make maps? The obvious idea is that we make a 2-D map which is our world on a smaller scale. But there is a problem with that. If the map is 2D paper then we can only sense the edge, so it's...
  35. A

    Solve 2D Elastic Collision: Prove 90° Angle Between Objects

    Homework Statement Object 1 with velocity v hits object 2, of same mass at velocity 2. Prove that the angle between them after the collision is equal to 90 degrees. Homework Equations PE inital = PE final KE initial = KE final The Attempt at a Solution P x component m1 x v1 + 0...
  36. T

    Static 2d body, force in member unknown

    Homework Statement Find stress or force in member AE Homework Equations torque = force x distance The Attempt at a Solution Solution out of book is 142 kN Attempts: Mb = -(200kN)(2.5m) + (.895AE)(5) + 510 = 111 Kn Mc = -(3m)(170kN) + (.895AE)(5) = 114 kN Md...
  37. S

    2D Perspective xform using CSS 3D matrix?

    Hi, I have used Mathematica to determine a 3x3 perspective transformation from one 2D image to another. Let's say that Mathematica gave me the following 3x3 matrix: a b c d e f g h 1 Now, moving outside of Mathematica, I'm trying to use that perspective xform it gave me in...
  38. E

    Momentum elastic colliion in 2D

    Homework Statement A hockey player of mass 8.0x10 kg was skating at a velocity of 7.5 m/s [E] when he accidentally hit a linesman who was just standing on the ice. The mass of the linesma is 9.0x10 kg and his velocity after the collision was 3.0 m/s [N30°E]. a) find the velocity of the hockey...
  39. H

    Is it okay to use 1D smoothing code for 2D path smoothing?

    Hi, I am trying to smooth a path defined in 2d by (x,y) which varies in time. I am using the Numerical Recipes 1d smoothing C code functions savgol() and convlv() to smooth x and y independently, which seem to do a pretty good job. However, while it seems to work, I was wondering if I should...
  40. M

    2d steady state conduction matlab help

    Homework Statement Hey guys, I am doing a steady state 2d heat conduction problem which is a 1mx1m cavity with three different wall temperatures on the 4 different walls. I am using the principle of superposition to work this out. What I want to do is plot a heat map on matlab. I...
  41. R

    How to find the unknown mass of an object in a 2d collision?

    Homework Statement I have two pucks colliding. PUck 1 has a mass of .545 kg. Puck two has the same puck mass, but also has a weight added onto it. I need to find the mass of puck two. Velocity before and after for puck 1: V1i = 2.0m/s[19°Below the Horizontal] V1f = 3.0m/s[31°Above the...
  42. S

    Exploring 2D Diffraction Spacing and Light Transmittance in 40um x 40um Lattice

    2D Aperture/Diffraction Spacing Hi, I have a 2D square spacing of 40um x 40um lattice. I am passing light through the spacing. I want to know how much of the light gets through... the transmittance. Clearly the light is being blocked by the surrounding lattice wires and the rest of the...
  43. C

    2D - Momentum Question, Grade 12 Canadian Physics

    Homework Statement 2 cars collide at an intersection. one car which has a mass of 1,400kg has a velocity of 45 km/h[S]; the other car has a mass of 1,300kg and has a velocity of 39 km/h[E] The cars has an inelastic collision. What are their velocity after the collision Homework...
  44. N

    Ordering Line Segments to form a 2D Polygon after slicing a 3D Tri Map

    I have a 3D shape described by a triangulation map i.e. a map between the vertices to the faces of the shape which are all triangles. I then sliced the shape by a plane and computed the intersections of the plane and the triangle faces. Each triangle face that intersects the plane, will have...
  45. M

    Sorting 2d array with qsort, keeping rows in order (C)

    I have been trying to get qsort to sort the rows of a 2d array I read in from a data file, and I have not been having much success to get it to do what I want. My array is a 4xarraysize array, where arraysize is the number of columns read in from a data file, with four entrees per row. I...
  46. S

    How Can Physics Predict the Danger Zone for Plants from Falling Snow?

    Homework Statement So...In Central Oregon there is a winter time problem that is troublesome to gardeners having to do with large masses of snow sliding off the roof and crushing plants and shrubs on the ground. Physics (in particular 2-D Kinematics) allows us to determine some features of...
  47. Geofleur

    2D Gauss' Law applied to an infinite cylinder

    Hello, I've been working my way through Mathematics for Physicists by Dennery and Krzywicki and, on page 65, they assert that Gauss' law applied to a 2D cross-section along an infinite charged cylinder is: ∫E.n dl = 4πσ where E is the electric field on the Gauss surface (a circle around...
  48. M

    Statics 2D Virtual Work problem regarding calculation of Normal force

    PROBLEM 1 Homework Statement The frame in the figure is supported by a hinge in A and a roller in G. It is loaded by a couple = 14 kN*m in B, a force = 12 kN in D and a distributed force = 4 kN/m on section EG. = 1.4 m. Calculate the normal force in C. Use the correct signs...
  49. A

    Solving a Rolling Bead's Motion in 2D Space

    Homework Statement a If the bead starts at the origin at time t=0, how long does it take for it to reach the end of the track (30m away in the figure)? Provide the answer in terms of v_{}. b How does the parameter α depend on time, ie. what is α(t)? d What is the velocity vector as a...
  50. U

    How Do You Calculate Displacement, Average Speed, and Velocity in 2D Kinematics?

    A motorist drives south at 20.0m/s for 3.00 min, then turns west and travels at 25.0m/s for 2.00 min, and finally travels northwest at 3.00m/s for 1.00 min. For the 60 min trip, find the total displacement, the average speed and the average velocity. I'm embarrassed how I still don't...
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