What happens when....

gilles

Rich are you still here?

Rich O Brien

@TIG

We have a winner

@Gilles

You had the right idea.

Another one?

gilles

Go on

Rich O Brien

If a vehicle is travelling faster than the speed of light what happens when it turns it's headlights on?

gilles

The speeds are added.

Rich O Brien

So if you were travelling next to the vehicle at the same speed would you see the light on of off?

gilles

They are on.

TIG

Question clarification.
Is that 'faster than the speed of light', 'at the speed of light' or 'approaching the speed of light' ?
Also is the vehicle traveling in a vacuum or in another medium where the speed of light might be lowered from 'C' ?

Also are we to postulate 'what happens' from the point of view of the car-driver/passenger or for a bystander watching the car pass by ??

Gaieus

@unknownuser said:

If a vehicle is travelling faster than the speed of light what happens when it turns it's headlights on?

@gilles said:

The speeds are added.

Wrong. Those speeds cannot be added.

From a more "realistic" example: when those jets pass the speed of sound, they literally "pas" it (overtake in British English) and "before" them, they do not have sound.

Back to the original post: it was obvious that the solution would be what TIG answered - you cannot deny that my answer was also entertaining though.

Rich O Brien

So the speed of light doubles?

Alan Fraser

If you were observing the car from a distance, you might see that the lights themselves were glowing (depends on the precise speed of the car and whether you, yourself, were travelling...and in which direction), but they wouldn't shine forwards like they normally do. If you were in the car, they would appear normal and would project forwards, as normal.

gilles

I'm sitting in a train, is speed is 250Km/h, I decide to go to the bar my speed relative to the train is 10Km/h ( I'm in a hurry I do need that beer!).
So what is my speed relative to the ground?

Alan Fraser

Are you moving forward or backward through the train?

gilles

Forward

Rich O Brien

1,930km/h

gilles

@unknownuser said:

1,930km/h

Could you show the formula?

Alan Fraser

250 km/hr + 10 km/hr + beer + another beer + another beer + double scotch + beer chaser.

gilles

Sorry but I go backward 20Km/h to the toilets

Rich O Brien

Well, I've made some presumptions...

Firstly I'm in a train travelling in the direction of the earths rotation. So I used simple addition

1,670km/h + 250 + 10

Aerilius

What if the train falls into the hole and you run upwards. Does the train then fall faster?