Every moving body travels with a [i]TNB frame[/i] that characterizes the geometry of its path of motion. The TNB frame - also called the [i]Frenet frame[/i] - consists of the unit tangent vector [math]\mathbf{T}[/math], the principal unit normal vector [math]\mathbf{N}[/math], and the binormal unit vector [math]\mathbf{B}=\mathbf{T}\times\mathbf{N}[/math]. These three vectors make a right-hand frame of mutually orthogonal unit vectors in space.[br][br]Slide the slider to move point [i]P[/i] along the path in the interactive figure.

[i]Developed for use with Thomas' Calculus, published by Pearson.[/i]