Up to A-level physics, you will have measured angles in degrees. You will be aware that there are 360 degrees in a circle, 90 degrees in a right angle and so on. Pilots and sailors amongst others know from navigation that we can divide a degree into 60 minutes and a minute into 60 seconds, giving 3600s per degree, so 1 second is l°/3600, which I am sure you will agree is a very small angle.
展开▼
