A lorry is travelling at 13.5 m/s along a stretch of road where the speed limit is 50 km/h.
1 kilometre = 1000metres
1 hour = 3600 seconds
show that the lorry is travelling below the speed limit.
It will do a lot more than that in an hour!
It will do a lot less km than metres in an hour
13.5*3600 / 1000 km/hour = 48.6km/hour
That is definitely less than 50km/h