1. Convert kilometers to meters:

* 1 kilometer (km) = 1000 meters (m)

* 120 km = 120 * 1000 m = 120,000 m

2. Convert hours to seconds:

* 1 hour (h) = 60 minutes (min)

* 1 minute (min) = 60 seconds (s)

* 1 hour = 60 * 60 seconds = 3600 seconds

3. Calculate the speed in meters per second:

* Speed = Distance / Time

* Speed = 120,000 m / 3600 s

* Speed = 33.33 meters per second (m/s)