For The Geeks On Here: Physics and Stop Sign Citation

[AeroEngineer1]

http://www.physicscentral.com/buzz/b...35810518469535

A guy in California used physics to get out of a stop sign citation. His logic seems sound, any takers?

[wantonebad]

Originally Posted by AeroEngineer1

http://www.physicscentral.com/buzz/b...35810518469535

A guy in California used physics to get out of a stop sign citation. His logic seems sound, any takers?

Aside from his argument you can get citations dropped just by showing up, not always but it does happen. The judge could have just decided he had better things to do with his time. My local jurisdiction pretty much lets you go if you dispute and you haven't done anything criminal. The one exception is cross-walk violations. If you've not stopped for a pedestrian and you get a ticket, you're going to pay it no matter how you dispute it. I tend to agree with that.

[Lmbeauleap]

That hurt my brain. I'm just going to try crying uncontrollably at the scene. I give an "A" for creativity though. I'd let him off too.

[GoldenBear]

I knew a guy that tried the same argument by flipping a coin in court. The coin rose, then stopped and finally fell. He argued it did stop but it couldn't be seen. The judge was amused...but he still had to pay.

[Timber Loftis]

Nice!

[Launch Mini]

Police will watch the rotation of the tires in relation to the road. This is a dead give away if a car is moving.
Try it, very easy to tell, at pretty much any angle except straight on, if the car has stopped.

[Welshwatchman]

Sounds like a pretend story to me, 1st April and all.

Notwithstanding that the author replaces a key "but" with a "by" in the introductory paragraph, it's all down to one simple sentence out of several pages of classical physics.

"Finally, in the last section, we consider what happens
if at that critical moment the observer's view is briefly
obstructed by another external object."

The supposed guy got off because the officer's view of the t=0 instance of the red-light-hopping was impaired, that's it.

All this angular momentum subjectivity is a red herring IMO since at t=0 the information from the car and the red stop light would be both be travelling at the speed of light to the officer's retina/brain. Then it's all down to his judgement call whereby he should give the car a 5 yard benefit of the doubt in any case.

The officer was probably photographed eating a donut around the time of the event. (stereotype alert)

Case dismissed.

[77T]

Originally Posted by Welshwatchman

The officer was probably photographed eating a donut around the time of the event. (stereotype alert)

I think you've wrapped it up nicely, Paul. In fact if you add a moment of inertia calculation to the angular momentum algorithm...perhaps I could convince you that the hammer in the "dummy" animated gif above isn't stopping after all.

[ManUtd]

Perhaps the judge and officer both pretended to be "convinced" when in reality they just wanted to avoid the headache of actually trying to discredit this guy's explanation.

[MoBe]

I reckon the judge was baffled and couldn`t mount an argument in favour of the police so he decided to give the physicist the benefit of the doubt and let it go.

[seand442]

Note to self: Don't write tickets to physics professors. However, When the truth fails, dazzle them with brilliance and baffle them with bull$hit. I believe that is the defense attorney method.

[Andad]

Originally Posted by Welshwatchman

Sounds like a pretend story to me, 1st April and all.

Notwithstanding that the author replaces a key "but" with a "by" in the introductory paragraph, it's all down to one simple sentence out of several pages of classical physics.

"Finally, in the last section, we consider what happens
if at that critical moment the observer's view is briefly
obstructed by another external object."

The supposed guy got off because the officer's view of the t=0 instance of the red-light-hopping was impaired, that's it.

All this angular momentum subjectivity is a red herring IMO since at t=0 the information from the car and the red stop light would be both be travelling at the speed of light to the officer's retina/brain. Then it's all down to his judgement call whereby he should give the car a 5 yard benefit of the doubt in any case.

The officer was probably photographed eating a donut around the time of the event. (stereotype alert)

Case dismissed.

You could be correct Paul but I think the judge let him off because he was driving a YARIS.

[GradyPhilpott]

Originally Posted by Welshwatchman

Sounds like a pretend story to me, 1st April and all.

http://arxiv.org/abs/1204.0162

[sherwin]

Originally Posted by Launch Mini

Police will watch the rotation of the tires in relation to the road. This is a dead give away if a car is moving.
Try it, very easy to tell, at pretty much any angle except straight on, if the car has stopped.

you have bigger issues than watching the tire thread straight on. the car might just be rolling your way

[joeychitwood]

As mentioned by some of the commentators on the posted story, the physicist is measuring the angular momentum of the police officer's head, not that of the car. The car is not rotating. It is going in a straight line. The officer's head is presumed to be rotating following the path of the car, but the cited equations only apply if the officer's eyes do not move in his rotating head. Also, the provided graphs only apply to objects with either constant linear speed or constant linear deceleration, neither of which would be the case in reality.

(PS: I can't believe I just spent 20 minutes on a Saturday morning analyzing the paper. Perhaps the true definition of a geek....)

[tranny]

Traffic court isn't Science - it's hardly even Law. It all depends on the judge and his or her mood that day.

I made a really good case for the same exact citation in FL, only I proved with photos that a high hedge prevented the officer from seeing my low sports car from his position when I was stopped behind the stop line, compounded by the fact that it was after dark. The judge didn't care, quickly shut me up, and fined me anyway.

I was sure I'd win that case. even the officer was about to concede after I presented, but the judge shut him up too (lol). I guess he was having a bad day. It happens.

And then I've had other judges who have dismissed charges with little proof or contention from my side.

If you fight a citation expecting to win, you'll likely be disappointed. Go into it assuming you lost already and have fun trying to work the system. If it's not fun for you, just hire a $60 lawyer, who will get better results than you will due to his relationship with the judge.

In the case of the above, the judge was probably having a good day, and was amused to see something new and different in his courtroom, and rewarded the defendant for the effort. A different judge may have been annoyed, disallowed the graphs, shut the guy up, and quickly ushered him out to hear the next case.