Curvature in terms of the tangent vector

Click For Summary
SUMMARY

The discussion centers on the derivation and equivalence of two curvature formulas: k = |dT/dt / |dR/dt| and k = |R' x R''| / |R'|^3. The unit tangent vector T is crucial in both equations, where k represents curvature. The relationship between the change in the unit tangent vector and the arc length is emphasized, confirming that |dT| represents the angle turned per unit length along the curve. The provided website serves as a resource for further clarification on these concepts.

PREREQUISITES
  • Understanding of vector calculus, specifically tangent vectors.
  • Familiarity with curvature definitions in differential geometry.
  • Knowledge of parametric equations and derivatives.
  • Basic comprehension of cross products in vector analysis.
NEXT STEPS
  • Study the derivation of curvature formulas in differential geometry.
  • Learn about the properties of the unit tangent vector in vector calculus.
  • Explore the relationship between arc length and curvature in parametric curves.
  • Investigate the application of curvature in physics and engineering contexts.
USEFUL FOR

Students and professionals in mathematics, physics, and engineering who are studying differential geometry and its applications in understanding curves and motion.

jaejoon89
Messages
187
Reaction score
0
My teacher wrote an alternative equation on the board for curvature, and I am wondering how it is true:

k = | dT/dt / |dR/dt| |

where T is the unit tangent vector.

I know k = |R' x R''| / |R'|^3 = |dT/ds|
but I am not sure about the formula in question. How is it true/derived?
 
Physics news on Phys.org
i think these are equivalent, i think the basic definition of curvature is |dT|/ds,meaning the angle turned over curve length traveled, indeed you can find |dT| is angle turned if T is unit tangent vector,and ds=|dR| where R is the position vector, and all the mentioned formulas can be derived.
 
Check out this website for clarification.

http://www.usd.edu/~jflores/MultiCalc02/WebBook/Chapter_14/Graphics/Chapter14_3/Html14_3/14.3%20Arc%20Length%20and%20Curvature.htm
 
Last edited by a moderator:

Similar threads

  • · Replies 10 ·
Replies
10
Views
1K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
1
Views
1K
  • · Replies 3 ·
Replies
3
Views
5K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 22 ·
Replies
22
Views
7K
Replies
9
Views
7K
Replies
6
Views
1K