If you are traveling along a space curve, the following three vectors are meaningful in describing your motion.[br][list][*][b]T[/b], the unit tangent vector representing your forward direction[/*][*][b]N[/b], the unit normal vector, giving the direction in which your path is turning, and[/*][*][b]B[/b], the unit binormal vector, defined [b]B = T x N[/b][/*][/list]Vector [b]B[/b] is related to the tendency of the motion to "twist" out of the plane created by T and N. Together, [b]T[/b], [b]N[/b], and [b]B[/b] define a moving right-handed vector frame that plays a significant role in calculating the paths of particles moving through space. The [b]TNB frame[/b] is also called the [b]Frenet frame[/b].

[i]This applet was developed for use with [url=https://www.pearson.com/en-us/subject-catalog/p/interactive-calculus-early-transcendentals-single-variable/P200000009666]Interactive Calculus[/url], published by Pearson.[/i][br]