Well, is it fake?

"Don't try this at home?"

If you have to ask...

http://www.youtube.com/watch?v=Kfwcrt8ufAM

As that old chestnut proves, Norwegians do it better.

Now that was really funny! Thanks Chief!

ATB from George

Steve,

Surely it has to be a fake as the speed of the car's movement around the centre of the tunnel (as opposed to its forward motion) is not that fast. Surely the centrifugal force generated would be insufficient. Besides, it's so easy to fake things these days, why would they take the risk?

Not on solid ground here. I didn't even do O-grade (Scottish O-level) physics.

Steve

quote:

What do you reckon?

Who cares...I'll have two of them?

JIm

quote:

Surely the centrifugal force generated would be insufficient

Centripetal force, the force acting towards the centre against the inertia of the mass [of the car in this case] to carry on in a straight line to produce a circular or modified circular motion, surely?

The other force at work in this [or these] case[s] is the gravitational force, and clearly the centripetal force must exceed the gravitational.

Think back to loop the loop calculations at A-level Physics and Mechanics. specifically Dynamics of masses [Maths branch]...

Why do people use the word centrifugal rather than centripetal to describe the force required to cause an object to move in a circular [or modified circular] motion when even A-levels physics should have taught the correct terminology?

ATB from George

quote:

Centrifugal force (from Latin centrum "center" and fugere "to flee") represents the effects of inertia that arise in connection with rotation and which are experienced as an outward force away from the center of rotation.

Outward from the centre means toward the tunnel walls and roof. Including, at some points, quite importantly, 'up'. Presumably the Centripetal force would be exerted by the walls, while the centrifugal force is the force generated by the speed of the car?

George,

I believe this may be right, but as I said I didn't even do O-level physics which would probably be one possible explanation of my failure to use the correct terminology. I believe the vast majority of the population didn't actually do O -level physics, so thinking back to those loop calculations might prove awkward for them.

Regards,

David

PS another possibility is that I'm right and it actually is centrifugal force that would be relevant here. That would explain it too.

I did take Higher Latin (roughly Scottish A level equivalent )

I gave Latin up at 13! I did not fire my imagination like Maths or Physics! I even got into University much later reading Civil Engineering, but the finances killed that ambition fairly soon [even in the first year], unfortunately!

The reality is that a centrifuge applies centripetal force to that with is being given an angular velocity in it.

This is where the common mistake comes in of using the term centrifugal force, rather than centripetal ...

Sorry to be a little pedantic, but where the science of physics is concerned then I hope that the top designers [such as aircraft designers] can get it right for all our sakes!

ATB from George

George,

I edited the post above after you replied. I'm getting interested now. Also came across this sentence.

quote:

Roller coaster cars are forced through a loop by the track applying a centripetal force on them. The reactive centrifugal force of the cars, associated with their inertia, holds them on the track.

I guess in this instance both forces are dependent on the speed of the car, but if it's the centrifugal force that holds it to the roof, you can understand why that would get all the attention.

Strictly speaking it is Inertia [the tendency of any mass to move infinitely at a constant velocity, i.e. in a straight line at a constant speed, in the absense of any forces applied - for examples, friction and gravity] that is at work rather than centrifugal force, and the notion of centrifugal force is like the centimetre, not actually scientifically accepted.

The correct units are the mm, and the metre. The centimetre is a convention that allows for people used to inches to cope!

ATB from George

There is a joke in F1 that their cars produce so much downforce they could be driven upside down in a tunnel if driven fast enough. Paradoxically an F1 car can lose grip and control if driven too slowly. The car in this film could not possibly produce anything like the downforce to run upside down for long (not that it has to). I would say it is possible to do what is shown in the film but why would they bother to risk it. I vote for fake. Also note the lights on the wall have been digitally removed in places.

As a visual effects supervisor, I advise TV and film shoots on this sort of thing all the time.

I would suggest doing it with a CG generated model. I also think if it were real, they would shoot it in a way to show that it was proving it is really real, ie. shots showing the camera crew, and all the people around.

Unless there is any claim made that it is for real, then I would say it is done with CG.

I would also say it is fairly typical of how much Merc drivers abide by the road rules.

Fake.

I had a basic physics for non majors in college, nice guy describing interesting things. then the final, really sweating if I could remember it all tho no major math involved.

He showed a roadrunner cartoon and we had to describe in essay what couldn't happen. I couldn't write fast enough, I'm sure every one got an A. It was only a 2 credit class.