Velocity and Acceleration Vectors in Spherical Coordinates: Part 2 - time derivatives of unit vector

The goal is to find the velocity and acceleration vectors in spherical coordinates. In this first part, I derive the spherical unit vectors in terms of cartesian coordinates. Part 1: Finding spherical unit vectors in terms of cartesian coordinates.    • Finding an expression for spherical unit v...   Part 2: Finding the derivatives of spherical unit vectors with respect to time.    • Velocity and Acceleration Vectors in Spher...   Part 3: Finding the velocity and acceleration vectors.    • Velocity and Acceleration Vectors in Spher...