Torsion Definition and 217 Threads

  1. S

    Why torsion free metric compatible connection ?

    why torsion free metric compatible connection ? Why in conventional GR we choose a torsion free, metric compatible connection? Can that be derived from somewhere like physical principles/postulates or it's just a the simplest convenient choice (many terms drop from equations) that produces...
  2. P

    Torsion Modules & Finite Generation: Investigating the Connection

    Homework Statement Does a torsion module M imply M is cyclic? Or does it imply M is finitely generated? I think cyclic implies torsion module. What about the reverse? The Attempt at a Solution I think there is a connection but don't see it.
  3. T

    Torsion tensor: Geometric interpretation

    Can someone pleas explain to me the geometric interpretation of Torsion? Why it is true is more important. Lol i said manifolds instead of torsion!
  4. D

    Prove: The Frenet Formula for Torsion & Curvature

    Homework Statement Suppose \alpha is a regular curve in \mathbb{R}^3 with arc-length parametrization such that the torsion \tau(s)\neq 0, and suppose that there is a vector Y\in \mathbb{R}^3 such that <\alpha',Y>=A for some constant A. Show that \frac{k(s)}{\tau(s)}=B for some constant B...
  5. T

    What Is the Physical Meaning of the Torsion Tensor in General Relativity?

    Hi, I've been studying extensions of general relativity with the torsion tensor and I have been wondering about the following fact: what is the physical meaning of the three indices of this tensor? That is, do these three indices represent some directions in space? (For example, the translation...
  6. P

    Solving for a unit speed curve given curvature and torsion (diff. geo)

    Homework Statement Find the unit speed curve alpha(s) with k(s)=1/(1+s^2) and tau defined as 0. Homework Equations Use the Frenet-Serret equations K(s) is the curvature and tau is the torsion T= tangent vector field (1st derivative of alpha vector) N= Normal vector field (T'/k(s))...
  7. dextercioby

    Phone Book's Fans: Shocking Claim on Torsion

    Here's something for the phone book's fans to chew on: Surprisingly, on page #1278, in the index entry "Torsion", the 3 authors claim that "(torsion) not present in affine connection if equivalence principle is valid" and hint further to page #250 where they don't debate on it. However...
  8. M

    Tangent, Normal, Binormal, Curvature, Torsion

    Okay, so I was asked to find all the things listed in the topic title given the equation: r(t)=(cos^{3}t)\vec{i} + (sin^{3}t)\vec{j} Now this is a lot of work, especially when it comes to finding the torsion \tau = - \frac{d \vec{B}}{ds} \cdot \vec{N} a total of four derivitives. Maybe I am...
  9. A

    Calculating Shaft Diameter for Torsion: Understanding the Formula

    I am trying to calculate the diameter of a drive shaft. I would have thought that all I would need in order to determine the diameter of a shaft (concerning torsion) would be how much torque is going to be applied to the shaft and the shear modulus rating of the drive shaft material...
  10. T

    Calculating Shaft Diameter for Bending & Torsion Loads

    what formula should i use to calculate the shaft diameter according to the load due to bending and torsion??
  11. H

    Hardness & Torsion Testing: Notes, Articles & Theories

    Hi there, can anyone just help me in finding articles, notes, theories about Hardness tests(Brinnel, Vickers, Rockwell) and Torsion test...please
  12. D

    Why is it called a torsion group?

    I've always wondered, and I can't seem to find out...
  13. T

    How is the Formula for Torsion Derived?

    Is anyone familiar with the derivation for this formula for torsion. \tau = \frac {\left( \begin{array}{ccc} \dot{x} & \ddot{x} & \dddot{x}\\\dot{y}& \ddot{y}& \ddot{y} \\\dot{z} & \ddot{z} & \dddot{z}\end{array} \right)} {|v \times a|^2} I know of expressing torsion as [tex] \tau =...
  14. M

    Solving Torsion Problems: Finding Torque & Rotation When Plastic

    Hi guys, Just a quick question. I have been attempting some problems to do with torsion. Most are pretty standard, you know, find the torque, angular rotation etc. However I am stuck on this one. I have calculated the torque and rotation for a shaft that's at its proportional limit...
  15. quantumdude

    Prismatic bar with noncircular cross section under torsion.

    I'm looking either for online resources or reference to a good book. I've been trying to help someone with a homework problem in a course entitled, Elements of Mechanical Design which uses Mechanical Design of Machine Elements and Machines by Jack A. Collins. The book sucks. The system...
  16. R

    Torsion Springs: Finding Formulas & Understanding Their Function

    Could someone please point me in the right direction for finding formulas dealing with torsion springs and also understanding more about how they work? Thanks Carla
  17. R

    Calculating Period of Torsion Pendulum

    A uniform meter stick is hung at its center from a thin wire. It is twisted and oscillates with a period of 5 s. The meter stick is then sawed off to a length of 0.76 m, rebalanced at its center, and set into oscillation. ****************** With what period does it now oscillate? Ok, I...
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