Final answer:
There isn't a universal minimum speed for interstates, but it is often around 40 to 45 mph, varying by jurisdiction. The conversion of 100 km/h yields approximately 62.14 mi/h and 80 km/h is about 22.2 m/s. Enforcement leeway for speed limits is often only a couple of miles per hour.
Step-by-step explanation:
If the posted interstate speed limit is 70 miles per hour, there is often a minimum speed you must maintain for safety and traffic flow purposes. However, each state might have different regulations and minimum speed limits. The question does not specify a particular jurisdiction and does not provide enough context to determine the exact minimum speed required. In general, minimum speeds on the interstate are often around 40 to 45 miles per hour, but this can vary.
The second question involves unit conversion from kilometers per hour (km/h) to miles per hour (mi/h). To convert 100 km/h to mi/h, you would use the conversion factor that 1.0 mile is about 1.609 kilometers. 100 km/h is thus approximately 62.14 mi/h.
Conversion from km/h to m/s can be achieved by using the fact that 1 km/h is equivalent to ≈ 0.27778 m/s. Thus, 80 km/h converts to approximately 22.2 m/s, and 100 km/h to approximately 27.78 m/s.
Finally, regarding how much over a speed limit you can drive without typically being fined: While there is certainly leeway given for small overages in speed, this can vary greatly depending on enforcement policies, road conditions, and other factors. Generally, driving a couple of miles per hour over the limit might not lead to a ticket, but anything more can increase the risk substantially.