* Angular velocity (ω) describes how fast an object is rotating around a central axis. It's measured in radians per second (rad/s).

* Tangential velocity (v) describes the linear speed of an object moving along a circular path. It's measured in meters per second (m/s).

Imagine a point on a rotating wheel. The angular velocity vector points along the axis of rotation, perpendicular to the plane of the wheel. The tangential velocity vector points in the direction the point is moving at that instant, which is tangent to the circular path.

Since the tangent line is always perpendicular to the radius of the circle at the point of contact, and the angular velocity vector lies along the radius, the two vectors are always perpendicular.