Here's why:

* Radians: Radians measure angles, and a full circle is 2π radians. Using radians allows for consistent and simpler calculations in physics and mathematics.

* Seconds: Seconds measure time, and angular speed tells us how quickly the angle changes over time.

Other units of angular speed:

While radians per second are the standard unit, you might also see angular speed expressed in:

* Degrees per second (°/s)

* Revolutions per minute (RPM)

Conversion:

* 1 revolution = 2π radians

* 1 minute = 60 seconds

Therefore, you can convert between different units of angular speed using these relationships.