>>>>And something similar from everyday life.
>>>>One day the speed of bypassing car might be measured with a ruler and a clock. The next day, if the same measurement gave a different answer, no one could tell if the speed of the car changed, the ruler length changed, or the clock ticking changed, or your car is moving differently, or your eyes became older.
>>>>
>>>>So what is here relativity for?
>>>>
>>>>>One day the speed of light might be measured with a ruler and a clock. The next day, if the same measurement gave a different answer, no one could tell if the speed of light changed, the ruler length changed, or the clock ticking changed.
>>>
>>>But here Cop's radar always is right :o)
>>
>>Radar works at the speed of the electro-magnetic spectrum too.
>
>Yes, maybe Radar is not the correct word, I mean these devices that cops used when they measured car speed.
>no metter what you said, cops are always right, so their devices are the standard for car speed :o)

Yeah, they're radar, aren't they, and work on the Doppler Effect principle. The hand-held, multi-directional ones are called, I think, Vascar.

Consider this:

A car approaches the speed of light and thus becomes close to infinitely long.
It arrives at its garage and, only having drum brakes, fails to slow down and stop, crashing into the back wall and stopping dead.

Does this mean only the front of it stops dead, because the rest of it, infinitely long, will need to contract into the garage to fit, therefore the back-end is still moving.

But how can this be? The car is rigid. You can't have parts of it travelling at different speeds.

This, before you smart-Alecs start, assumes the car is made of crumple-proof, really tough material, spec'd to survive such collisions.