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## Main Question or Discussion Point

Please help me in the folowing problem:

It is well known that the radar echo (police radar) establishes a relationship between the period T(e) at which a stationary observer emits successive light signals and the period T(r) at which he receives them back after reflection on an object that moves with constant speed V. Both time intervals are measured as a difference between the readings of the observer's wrist watch and so IMHO no clock synchronization is involved. If the moving object is receeding the two periods are related by

T(r)/T(e)=(1+V/c)/(1-V/c).

My question is: Does the measurement of the speed V involve clock synchronization?

Thanks in advance for an answer in the spirit of netiquette!

It is well known that the radar echo (police radar) establishes a relationship between the period T(e) at which a stationary observer emits successive light signals and the period T(r) at which he receives them back after reflection on an object that moves with constant speed V. Both time intervals are measured as a difference between the readings of the observer's wrist watch and so IMHO no clock synchronization is involved. If the moving object is receeding the two periods are related by

T(r)/T(e)=(1+V/c)/(1-V/c).

My question is: Does the measurement of the speed V involve clock synchronization?

Thanks in advance for an answer in the spirit of netiquette!