> That is literaly measuring car's speed at every instant! Well, there's no way to measure to measure speed instantly, it's always over some period even if sma

> That is literaly measuring car's speed at every instant! Well, there's no way to measure to measure speed instantly, it's always over some period even if small (take some time interval and see how much distance have been covered). For example, at time zero you cannot know what speed the car has. Similar like when I was working with audio, producing frequency diagram -- the frequency cannot be gathered from a single timestamp on the waveform, you always need some interval, like 20ms to get an FT.