# Car at the Speed of Light

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If a car travelled at the speed of light would the headlights work?

Pud

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Nope, but the tail lights would look great following along behind

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Yes, but you wouldn't see anything.

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Of course they'd work. Energy doesn't just disappear. But man alive, they'd be bright wouldn't they? And REALLY close when you did see them...

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Yes.

The light from the headlights would still travel away from the car at the speed of light (c). Also to someone on the side of the road watching the light from the headlights, it would still travel away from the car at c and not at 2c. This is because of Einstein's theory of special relativity, which states the speed of light remains constant for all observers and so time will dilate, length will contract and mass/momentum will dilate to assure that c remains constant.

An easy way to see this is with the fact that speed=distance/time.

So if speed (the speed of light) remains constant then distance and time have to change.

Ahh physics....

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Yes.An easy way to see this is with the fact that speed=distance/time.

So if speed (the speed of light) remains constant then distance and time have to change.

Ahh physics....

Say what???... if speed remains constant then distance and time have to change??? If that happened you'd have a variable constant...

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The speed of light doesn't change... i.e., it's the constant in this case...

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Say what???... if speed remains constant then distance and time have to change??? If that happened you'd have a variable constant...

Light is the constant. And for the speed of light to remain constant distance and time will change. Time to drag out my old notes for an example...

For example, someone is sitting on a train traveling at the speed of light and decides to look at their reflection in a mirror. They will of course see their reflection as normal. Seeing as the train is traveling at c, an observer outside the train would see that the light from the person doesn't 'catch up' to the mirror hence there would be no reflection. But according to relativity, length contracts and so the person outside the train will 'see' that the light has a shorter distance to travel and hence they will also see the person on the trains reflection as normal.

Not a very good example but still.

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I think I thought that we don't know what we don't know. Or did I?

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Of coarse they'd work. The question should be, would they produce a beam of light in front of the car, and I'm not buying into this one.

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Of coarse they'd work. The question should be, would they produce a beam of light in front of the car, and I'm not buying into this one.

Yes they will.

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If a car travelled at the speed of light would the headlights work?Pud

See what you've done Pud??? Is that a Kookaburra larfin' outside your window???

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See what you've done Pud??? Is that a Kookaburra larfin' outside your window???

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Oh, No..... it took us years to get over the plane landing on a moving belt. Now look at what YOU'VE started Pud. Have you heard the one about turns downwind???? Don

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So, if you were driving along at the speed of a bullet, and you shot the bullet ahead... what will happen?

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So, if you were driving along at the speed of a bullet, and you shot the bullet ahead... what will happen?

The bullet will have it's speed plus the speed of the car (So bloody fast)

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So' date=' if you were driving along at the speed of a bullet, and you shot the bullet ahead... what will happen? [img']https://www.recreationalflying.com/xf2/uploads/emoticons/075_amazon.gif.0882093f126abdba732f442cccc04585.gif[/img]

Come on Pud,,, you started this... Your turn...

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If you shot it astern it would drop more or less straight down.

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Now if you were driving your latest model Ford car at twice the speed of light, you would finish up very quickly with a Model T Ford,

and the sound would catch you up in two light years along with the bullets that Al Capone shot from the Model T.

Alan Capone (a distant relative) according to the laws of relativity.

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Does more or less = almost? Image ourselves standing off to the side when the car went speeding by and the bullet was fired... What would we see the bullet do?

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If you shot it astern it would drop more or less straight down.

It's just as well the Lancaster Bomber couldn't fly at that speed because the tail gunner would never hit the Messerschmit.

That statement will draw a few replies, cos I can think of a few already.

I might have to put up with it and just bite the Bullet.

Gunner Alan.

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So, if you were driving along at the speed of a bullet, and you shot the bullet ahead... what will happen?

Come on Pud,,, you started this... Your turn...

I don't bloody know!!

I just asked the question:augie: But I reckon the bullet won't just dribble out the barrel and the road ahead would be illuminated.

Another one for ya.... Is the car pushing or pulling the trailer?

Pud

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Another one for ya.... Is the car pushing or pulling the trailer?

Pud

Hint: What's the towball doing to the hitch?

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Does more or less = almost? Image ourselves standing off to the side when the car went speeding by and the bullet was fired... What would we see the bullet do?

More or less=Accounting for air resistance.

I saw them do a myth on mythbusters regarding the firing something backwards with the same speed as a car moving forwards. Surprisingly it did drop pretty much straight down (Air resistance) at a range of velocities. While the projectile is in the barrel of the moving car, it may as well be not moving at all. The 'shot' will accelerate it down the barrel and until it leaves it is as if the cannon was sitting still on the ground. But while it is accelerating down the barrel, lets say to 100km/h, the car is traveling the opposite direction at 100km/h. So relative to the car the projectile will accelerate to 100km/h and leave the cannon, but relative to anyone watching it the projectile was already traveling at 100km/h (To the left for arguments sake) and the firing of the cannon has essentially slowed it down like a brake so that when it leaves the cannon it has no velocity, and hence drops pretty much straight down.

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Oh, No..... it took us years to get over the plane landing on a moving belt. Now look at what YOU'VE started Pud. Have you heard the one about turns downwind???? Don

No Don, It was the plane taking off from the moving belt thread.

Just like the falling pot plant in the Hitch-Hikers-Guide, I find myself thinking, "Oh no, not again!"

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