English: Diagram of a particle at radius vector r with velocity V showing the radial and tangential components of the velocity, the angle of the radius vector with respect to the x axis and the angle of the velocity vector with respect to the radius vector.
Diagram of a particle at radius vector r with velocity V showing the radial and tangential components of the velocity, the angle of the radius vector with respect to the x axis and the angle of the velocity vector with respect to the radius vector.