Here's how to convert the train's speed from kilometers per hour to meters per second:

1. Convert kilometers to meters:

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

* So, 120 km = 120 * 1000 = 120,000 meters

2. Convert hours to seconds:

* 1 hour = 60 minutes

* 1 minute = 60 seconds

* Therefore, 1 hour = 60 * 60 = 3600 seconds

3. Calculate the speed in meters per second:

* Speed = (Distance in meters) / (Time in seconds)

* Speed = 120,000 meters / 3600 seconds

* Speed = 33.33 meters per second (approximately)

Therefore, the train's speed is approximately 33.33 meters per second.