Raymond B. answered 07/22/21
Math, microeconomics or criminal justice
when the posted speed limit says 70 mph, it refers to instantaneous rate of change.
It's not a defense to say your average speed was only 65 mph
You could prove you drove for 1 hours and traveled 65 miles, which means just 65 mph average speed, but if at any point during that hour you drive faster than 70 mph, you may get a speeding ticket
the police officers' radar measures instantaneous rate of speed, not average speed. It measures instantaneous rate of change of distance = instantaneous speed or velocity.
You go 75 mph for half an hour, then 65 mph for half an hour
you travel 75/2 + 65/2 = 140/2 = 70 miles in one hour. You average speed is 70 mph
Your instantaneous speed was 75 mph for 1/2 an hour, and 65 mph for 1/2 an hour
for half an hour you might see some flashing red lights in your rear view mirror