Modified Car and ditch paradox

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    Car Paradox
In summary, the paradox presented is about a car moving at relativistic speed on a road with a ditch that should be too small for the car to fall into. However, a modification is made that allows the car to cross the ditch if two of its rear tires are on the road and two of its front tires are hanging in the air. This raises the question of whether the car will fall into the ditch from the perspective of the road or if it will be able to pass without trouble from the car's perspective. The solution to this problem is that the car will always crash into the opposite edge of the ditch regardless of the frame of reference. The modification to the problem is unphysical due to the fact that simultaneity is frame
  • #1
I_am_learning
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Modified Car and ditch paradox!

Suppose there is a car moving on a road in relativistic speed. The road has a ditch (hole) which is litter bigger than the car when both are at rest.

Modification: Assume that the car will fall on the ditch if all of its tyres are in the air at the same time. If two of the rear tyres rest on the road and two of the front tyre hang on the air, the car won't fall in the ditch; it can move as if all of its tyres are on road.

Now the problem is, car seem to fall on the ditch on the
roads perspective whereas in the cars' perspective it can pass the ditch without trouble.
The question is Will the car fall in the ditch?

(Though I have much understood much of S.R. I got stuck on this. I know that: though in the road's frame of reference the two rear and the two front wheels seem to be in air at the same instant its not the case in the car's frame of reference. In the car's perspective they occuur one after the other.
But anyway, it can't be that --> for the car it can escape the ditch AND for the road it can trap the car.? )
Have attached picture for visualization.
 

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  • #2


thecritic said:
Modification: Assume that the car will fall on the ditch if all of its tyres are in the air at the same time. If two of the rear tyres rest on the road and two of the front tyre hang on the air, the car won't fall in the ditch; it can move as if all of its tyres are on road.
"at the same time" according to whom? Since simultaneity is frame-dependent, your modification is unphysical.
 
  • #3


thecritic said:
Suppose there is a car moving on a road in relativistic speed. The road has a ditch (hole) which is litter bigger than the car when both are at rest.

Modification: Assume that the car will fall on the ditch if all of its tyres are in the air at the same time. If two of the rear tyres rest on the road and two of the front tyre hang on the air, the car won't fall in the ditch; it can move as if all of its tyres are on road.

Now the problem is, car seem to fall on the ditch on the
roads perspective whereas in the cars' perspective it can pass the ditch without trouble.
The question is Will the car fall in the ditch?

This is a variation of a familiar problem. And it suffers from the same weakness. Your modification to the problem contradicts reality. That makes any solution meaningles. The truth is, this is a very difficult Mechanical Engineering problem. The other side of the ditch must be lower by a certain amount for the car to make it across no matter whose Physics you use (Newton's or Einstein's). That means it will always crash into the other edge. So why not just mark a spot on the opposite edge where it hits. Then the problem is to verify that it will hit the same spot wheather you observe the action from the ditch or as a passenger in the car.

Hint: Remember that velocities don't add the same intuitive way using Special Relativity. The vector sum can never reach "c". So, the faster the car goes along the road, the less downward velocity is available for it to acquire when it's hovering above the ditch. At .9c it will drop much less than expected before it hits the opposite edge. Now switch and be the observer in the car. The car is at rest and can acquire all the downward velocity it wants once its above the ditch. But the ditch is moving at .9c and is much narrower. So the car hits the opposite edge in the same spot. Make sense?
 
  • #4


Doc Al said:
"at the same time" according to whom? Since simultaneity is frame-dependent, your modification is unphysical.
To tell According to roads view.
To make the modification sensible assume that on the both side of the roads are pressure sensors. As long as at least one sensor is kept pressed all is fine. But whenever there is no pressure in all of them at the same instant (from the road's frame) a robotic arm that emerge from the ditch will snatch the car.

I think this is the answer now ? --> The car's driver, Having known the arrangement of the road, but now happy about the contracted ditch's length, would try to cross the ditch casually. But alas, the contracted length is only a mirage, he is snatched away!
 

FAQ: Modified Car and ditch paradox

What is a modified car?

A modified car is a vehicle that has been altered or customized to improve its performance, appearance, or both. This can include changes to the engine, suspension, body, or interior.

What is the ditch paradox?

The ditch paradox is a thought experiment that explores the concept of time travel. It asks the question, "If a car travels back in time and crashes into its past self, creating a paradox, how is the paradox resolved?"

Can a modified car be used to prove or disprove the ditch paradox?

No, a modified car cannot be used to prove or disprove the ditch paradox. The paradox is a theoretical concept and cannot be tested in reality.

Are there any real-life examples of the ditch paradox?

No, there are no known instances of the ditch paradox occurring in real life. It is purely a thought experiment used to explore the concept of time travel.

How does the ditch paradox relate to scientific theories and principles?

The ditch paradox is a way to examine and challenge our understanding of time, causality, and the laws of physics. It can be used to explore theories such as the Grandfather Paradox and the Novikov self-consistency principle.

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