Angles Definition and 911 Threads

  1. N

    Why do photons/electrons scatter at angles in compton scattering?

    This is something that I always just took for granted, but I have no idea how a photon scatters off of an electron at an angle other than 0 or 180 degrees. I haven't seen this mentioned in a modern physics or nuclear engineering textbook either, so I assuming its a pretty complicated reason?
  2. U

    Centrifugal compressors some details on work done and vane angles.

    1. As far as the derivation goes, Cp(T02-T01)= Euler work= U2Cx2 in a centrifugal compressor... where T01 and T02 are the stagnation temperatures...however, in a solved problem in my book, it writes: Cp(T2-T1)= Euler work= U2Cx2...and therefore uses static temperature instead of stagnation...
  3. D

    Undefined angles for Compton scattering

    Homework Statement Hello, I need to find which values for θ and ψ are not defined for the Compton scattering. Where θ is the angle of the electron and ψ is the angle for the photon.Homework Equations I have attached the formulas I´m using. http://tinypic.com/view.php?pic=v4z2qf&s=5The Attempt...
  4. C

    Conservation of momentum with unknown angles

    Homework Statement Ma=2900kg Mb=730kg Va1=11m/s Va2=9m/s Vb1=30m/s Vb2=32.54m/s ∅=49.14 Homework Equations (2900kg)(49.14)+(730kg)(30m/s*cos(25))=2900kg(9m/s)(cos(α))+730kg(32.54m/s)cos(β) and (2900kg)(11m/s)+730kg(30m/s*sin(25))=2900kg(9m/s)sin(α)+730kg(32.54m/s)sin(β) The...
  5. A

    Help needed with direction angles and vector equations

    Homework Statement A line has direction angles 60°, 45°, 60° and passes through the point (1, -2, 5). Determine the vector equation of this line. Homework Equations I honestly have no clue. My teacher gave a hint it has to do with trig (as in the trig ratios) and the unit vector...
  6. J

    Using angles of 2 balls at time of collision for new directions

    If i have 2 circular objects like coins and their moving on a frictionless surface and i know their velocity angles mass, how can i find the angle of each object after they collide, an example A is the first coin, B the second their masses are the same. X will be the x of a vector and Y the y...
  7. L

    Calculating torque, force and angles

    Homework Statement A lever is used to lift a box, ignore the mass. the lever makes a 43° angle at the pivot, point A, the length of the lever is 1,8 m, Force P is apply 15° at the end of the lever Force P causes a moment of 500N.m about point A. Determine the force P? Homework Equations...
  8. E

    Calculating the Moment of Inertia for a Weird I-Beam with Angles

    So I'm trying to check the moment of inertia Ix for this weird I beam. The three steel plates' moments of inertia were easy enough to calculate. However, I would appreciate any help on how I should go about calculating the contribution of the four L6x6x1 angles to the total moment of inertia...
  9. F

    Interpreting QPSK Modulation Angles

    Hello, I have attached a diagram of QPSK modulation angles. I was wondering how would the red and yellow dots be interpreted. Those dots are not exactly on either of the 4 different phase angles. But I understand QPSK has a discrimination of 90 degrees so would the red equate to 45 degrees and...
  10. M

    Usiing angles and height to calculate height/altitude of object

    Pre-requisite: Protractor Requirement: Both the measurers and the object should be perpendicular to the ground One-Person Method: Find point A, the point whose vertical distance to the ground you want to measure. If you're measuring the height of an object, this will be the top of the...
  11. A

    Tension in Cables of Differing Angles

    Homework Statement α=30° β=45° m=10kg a=0 Tα=unknown Tβ=unknown THE ANSWERS SHOULD BE Ta=72N, Tβ=88N Homework Equations mg=10kg*9.8m/s2=98N ∑Fx=ma(x)=0 ∑Fy=ma(y)=0 A Free Body Diagram would show three forces: 98N facing downwards, Ta facing 30° up and to the left, and Tb...
  12. C

    Solving 3D Chart Axes Angles Problem with Wikipedia

    Yes, that is my problem. I could never reproduce in computer the scheme I learned in Computer Engineering graduation I am coursing. The way the teachers show and in some books, I never get into that result but I don't know if it is exactly impossible. At this page in wikipedia...
  13. T

    Geometry, logic and sun angles: help

    I am trying to figure out what size eaves we need for our house extension. I've tried a few calculations and now I'm posting here in the hope that a logical thinker will be able to tell me what I'm doing wrong. We live in Adelaide, Australia, and we want to put in glass double-doors on a...
  14. L

    Problem with variable capacitor and changing angles

    Homework Statement Here is the problem: A variable capacitor has seven armatures in the shape of half-circles with a radius of 2 cm. The armatures have a distance of 1 mm separating them. Find the capacity when the angle θ is: (a) 0 degrees; (b) 45 degrees; (c) 135 degrees. Homework...
  15. M

    What Must Be the Angle Between Two Vectors of Equal Magnitude?

    Homework Statement Two vectors A and B have precisely equal magnitudes. In order for the magnitude of A+B to be 120 times larger than the magnitude of A-B , what must be the angle between them? Homework Equations None (i think) The Attempt at a Solution A+B=120(A-B)...
  16. M

    How do I find the tension and angles in a spider's web?

    Homework Statement A spider is resting after starting to spin its web. The gravitational force on the spider is 0.165 N on the junction of three strands of silk. The junction is supported by different tension forces in the two strands above it so that the resultant force on the junction...
  17. N

    Interior angles of polygon on a sphere

    Hi can anyone help me out with finding the interior angles of a pentagon on a sphere. I know two of the interior angles already and I know all the angles that correspond with the arc lengths of the sides of the pentagon. How do I find the other three interior angles? Thanks
  18. B

    What are the Bond Angles in Cyclopropane?

    Cyclopropane is a cycloalkane with three carbon atoms. Each carbon is bonded to two hydrogens as well as the other two carbons, forming a triangular bond between the three carbons. Each carbon has a tetrahedral molecular geometry since it has sp3 hybrization. However, I am rather confused...
  19. I

    How Does Special Relativity Affect the Angle of a Meter Stick in a Moving Frame?

    Homework Statement A meter stick is at rest in the laboratory frame. It lies in the x-y plane, making an angle of 30° with the x-axis. What angle does this meter stick make with the x'-axis of a reference frame moving at V=0.8c in the x-direction. Laboratory frame is the rest frame...
  20. P

    Solve for x, y and 4x in 4x+x+y=280^0

    Homework Statement We have ##4x+x+y=280^0##(degrees), find ##x##, ##y## and ##4x##. Homework Equations ##4x+x+y=280^0## The Attempt at a Solution ##4x+x+y=280^0## ##5x+y = 280^0## ##5x=280^0-y## ##x=\frac{280^0-y}{5}## ##x=56^0-y## ---------------------...
  21. J

    How to calculate vector angles and magnitude

    Ok I am a little stuck and really need some help as I am pretty new with physics...im not sure if this question is really simple or if i need a little algebra to help find the answer. Q : 10 units, 30 degrees counterclockwise from the positive side of the x-axis :25 units, 45...
  22. P

    Solve for a and b | Homework Help on Angles | 900 = a + b, a = b/14

    Homework Statement This is the problem: ##a+b=##900 (degrees) ##a=\frac{b}{14}## Find a and b. Homework Equations ##a+b=##900 (degrees) ##a=\frac{b}{14}## The Attempt at a Solution ##a+b=##900 ##(\frac{b}{14})+b=##900 ##\frac{b + 14b}{14} (14 and 14 get simplified)=## 900...
  23. V

    Solving for Euler angles and 3-D coordinate Rotations.

    Hi, (attachment with visuals is included) I have a 3-D vector dataset that is measured in a reference frame (measurement reference frame) that is oriented relative to a horizontal coordinate system. In this dataset I have x-y- and z-component data for the vectors relative to a coordinate...
  24. B

    Wording question regards angles

    I have two angles: θ: and θ_{1}: θ_{1} = θ How do I differentiate the two angles? I want to say "leftward facing" and "rightward facing", but I'm not sure how to "mathematically." Note that I must talk about the angle that's between 0-90 degrees. Thanks, Ben
  25. J

    Euler angles. Quantum Mechanics Question

    Homework Statement Let U = e^{iG_{3}\alpha}e^{iG_{2}\beta}e^{iG_{3}\gamma} where ( \alpha, \beta, \gamma ) are the Eulerian angles. In order that U represent a rotation ( \alpha, \beta, \gamma ) , what are the commutation rules satisfied by the G_{k} ?? Relate G to the angular...
  26. H

    Linear Algebra - Use angles between vectors to find other vectors

    Homework Statement Find all the unit vectors X element of R^3 that make an angle of pi/4 radians with vector Y = (1,0,1) and an angle of pi/3 radians with vector Z = (0,1,0) Homework Equations For any two vectors X and Y element of R^n, the dot-prodict of X and Y is equals to the...
  27. S

    SinX is defined for any angles [0,∞) ?

    SinX is defined for any angles [0,∞) ? Homework Statement SinX is defined for any angles [0,∞) Homework Equations Ok, the domain of sinX is -∞< x < ∞ The Attempt at a Solution Someone said "You are confused due to fact that Sin(-x)= - sin(x)." Does it mean that just because sinX...
  28. J

    Projectile Motion: Finding angles given velocity and impact coordinates

    I'm not looking for someone to work this one out for me, and I know I have done this type of problem in entry level physics, but it's popped up again in dynamics, and physics is mostly a blur these days. Given the muzzle velocity and impact coordinates of a rifle, find the angles of elevation...
  29. A

    For what angles can the exact value of all trigonometrig ratios be found?

    I have learned a lot of formulas for converting trigonometric values, but when I looked up sin(pi/10) I got the exact answer (1/4)(√5 +1). I tried to arive at this using formulas, but I couldn't. How is this found? What other angles can be found exactly. Ps. I already know about how taylor...
  30. C

    Caster Angles in Shopping Carts: How to Control Wheel Paths

    Can you draw a force diagram to explain how a positive caster angle makes wheels return to a straight line in a shopping kart (as an example), while a negative caster angle would have the opposite effect. Thx
  31. S

    Angles between normals at 2 points on a surface

    I have been reading about the normal vector to a point on a surface. http://mathworld.wolfram.com/NormalVector.html Can anyone explain if I have normals to 2 points on a surface and I want to compute the inclinations between them, how would one proceed?
  32. T

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

    See attachement for required information. Please and thank you!
  33. R

    Why Choose Radians Over Degrees for Measuring Angles?

    What are the advantages to using one system to measure an angle over another. For example why do we measure angular velocity in radians instead of degrees? Are there any intrinsic advantages to one unit over another? Thanks AL
  34. T

    Calculating work done with angles

    Hi all. I am trying to learn more on physics, and am at the subject on calculating work done. The formula to calculate work done is Work done = Force * Dislacement * consine(theta). I am on a question which explains: a 100N force is applied at an angle of 30 degrees to the horizontal to...
  35. P

    How Do You Calculate the Angle for Retroreflection in a Diffraction Grating?

    1. Homework Statement I'm choosing an angle for a diffraction grating such that a laser of particular wavelength λ is retroreflected (reflected back along incident path). 2. Homework Equations If you have a better way than using the equation below, feel free to explain. The book that I'm...
  36. P

    How Do You Set the Angle of a Diffraction Grating for Retroreflection?

    I'm choosing an angle for a diffraction grating such that a particular wavelength λ is retroreflected (reflected back along incident path). The book that I'm looking through treats the blazed diffraction grating as a set of N slits. This results in the equation...
  37. P

    When to use alpha vs theta for angles

    Pretty simple question. When we draw triangles or other pictures with angles, when do we mark the angles as alpha and when do we mark them as theta? Is there some kind of convention or is it just whatever is free in the equation? It makes sense to me to use alpha for the first angle then...
  38. H

    Angles and rotational equilibrium

    Homework Statement This is not a homework question, I was just curious. I'm trying to find the angle θ that an unbalanced arm produces in the following case: Homework Equations τ=rF The Attempt at a Solution τ1=τ2 rF=rF r(98 N)(cos θ)=r(49 N)(cos θ) However, the cos θ...
  39. E

    Finding the a vector using angles

    I have three non-parallel vectors (whose components are known), v0, v1, v2 and I'd like to find a fourth unit vector, v3, given only the angles between: psi, angle between v0 and v3 theta, angle between v1 and v3 phi, angle between v2 and v3 I know that they are related by the dot product: v0...
  40. P

    Forces with angles, Find the acceleration

    Homework Statement Two forces act on a 4.00 kg mass which is sitting at rest on a horizontal frictionless surface. One force is 6.50 N directed 55° West of South, the other is 7.00 N directed 25° North of West. What acceleration does the mass receive? Homework Equations sin = o/h...
  41. L

    Triangle Angles: Find b & c with A-B-C given

    I am stuck on the job; I need to find the angles. It’s not an angle or side based triangle, just a right triangle. The lengths are known, A-B-C. What I need to know is the angles, a-b-c. So, a=90*, what formula could I use to find b, and c? Sorry, please make it easy enough for me to work it...
  42. S

    Relative speed, relative angles

    Homework Statement A kayaker needs to paddle north across a 100-m-wide harbor. The tide is going out, creating a tidal current that flows to the east at 2.0 m/s. The kayaker can paddle with a speed of 3.0 m/s. Homework Equations v= v + V Let the Earth frame be S and a frame attached...
  43. B

    Why do trigonometry angles go counter-clockwise?

    The idea of a circle divided into 360 degrees that goes clockwise has been around for thousands of years (see orienteering compasses). So, why do radians and angles in trigonometry go counter-clockwise and start off pointing to the right? Was that on purpose?
  44. R

    Problems with finding angles with different signs

    I need to find all angles that are greater than 90. To be more precise I need to find the entries that are to the right of the blue line and to the right of the red line. I tried using the the find command in MATLAB to find certain indices but realized that the angle signs change. The blue and...
  45. M

    Calculating Tension in Suspended Ball with Angles

    Homework Statement A ball of weight 5 Newtons is suspended by two strings as shown above. Determine the magnitude of each of the forces, T1 and T2. (Note: sin 37° = 0.6; cos37° = 0.8) Homework Equations T = mg The Attempt at a Solution I couldn't go anywhere because I need a...
  46. C

    Angular velocity of a 3D rigid body with Eulerian Angles

    Say I have an odd shaped rigid body in pure rotation. I fix an orthogonal x-y-z coordinate system to the body, and coincide the origin of this coordinate system to the origin of my global coordinate system X-Y-Z. I have 3 Eulerian angles (as functions of time) which I can use to describe the...
  47. O

    Proving these two angles are equal

    I'm researching an abstract geometric property and I've discovered the problem depends on showing these two angles are equal for strictly positive x: arctan(x) - arctan(x^3 +2x -((x^2 + 1)^(3/2))) and -arctan(x) + arctan(x^3 +2x + ((x^2 + 1)^(3/2))) Any help would be greatly...
  48. R

    Calculate Angles from Diameter for Lathe Arm

    The manual lathe I work on has a degree scale for the arm. I have the radiuses in mm and the diameters in mm of two zones I have to cut. What formula can I use to determine the angle which delimits the two zones? For example: Say I have an item 15mm in diameter. Inner zone A is to have a...
  49. T

    Can angles be negative in coordinate geometry?

    Homework Statement Can you have a negative angle, or do you just assume absolute numbers? Your coach tells you to turn south for 10.0m and then turn and run east 15.0m. How far must the ball be thrown from where you started to where you ended? Homework Equations a^2 + b^2 = c^2...
  50. S

    Finding Displacement with angles and directions

    Homework Statement I am having a nightmare doing homework for my physics test. I have figured out part of the answer but can not figure out what the angle of the displacement is and its driving me crazy... The teacher showed us two methods of how to find the answers, but ended up making...
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