Tangential component
= Tangential component
{title2=$w_T=w-w_N$}
The tangential component is the <orthogonal projection> of a <vector> onto the <tangent space>. For a <plane curve>, it is $(w\cdot T)T$; for a <hypersurface>, it is $w-(w\cdot n)n$. The scalar tangential component of <acceleration> is $\dot v$, which can be positive, zero or negative as the <speed> increases, remains constant or decreases.