For instance, the motion of a spacecraft, regarding its orbit and attitude , is described by the relativistic theory of classical mechanics, while the analogous movements of an atomic nucleus are described by quantum mechanics.
According to the NHS, the average Briton walks between 3,000 and 4,000 steps a day - significantly less than the Fitbit target. Yet many people do significantly more, and for them 10,000 steps might not be much of a target.
It is recommended that you begin walking as much as feels comfortable to you, then aim to walk in increments of 1,000 to 2,000 steps more each week until you're comfortably at 10,000 steps a day. There is nothing stopping you walking more than this each day, but the aim is to always make 10,000 steps.