Final answer:
Speed limits on highways are posted in km/h or mph; 100 km/h equals 62 mph or 27.778 m/s. The de jure speed limit is the official posted limit, while de facto speed limit refers to the threshold before potential ticketing by police.
Step-by-step explanation:
Understanding speed limits on highways involves converting different units of speed to understand their equivalences. For example, a speed limit of approximately 100 km/h on some interstate highways is equivalent to about 62 miles per hour (mph), since 1.0 mile is approximately 1.609 kilometers (km). To convert this to meters per second (m/s), you would use the conversion factor that 1 km/h is equal to 0.27778 m/s. Therefore, 100 km/h is equivalent to 27.778 m/s.
It's essential to note that while the de jure (legal) speed limit is the one posted on road signs, the de facto speed limit may be somewhat different, as law enforcement may allow a small amount of leeway over the posted limit before issuing speeding tickets. However, consistently surpassing the speed limit can lead to penalties or fines.