If Einstein is right, something is wrong with our ideas of space and time!
- The 2nd Postulate implies that a special velocity (that of light) is an ABSOLUTE quantity.
- Every other velocity we know is a RELATIVE quantity: VAC= DAC/t = (DAB+DBC)/t = VAB+VBC
This is our experience in everyday life.
- The velocity of an object (e.g. a car) or a wave (e.g. sound) is relative to the observer. It is different as seen by different observers!
Example: Ambulance and sound wave in Java demo from the course links http://home.a-city.de/walter.fendt/phe/phe.htm