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Zenister

Lexus Commercial and Physics?

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Is that possible by that particular Lexus? My guess is yes, since a "1 G" car is kinda of a buzz-word for performance cars and I seriously doubt that they'd make that commercial if it didn't live up to the claim.



They didn't make a claim! They made a slogan, something about beating gravity or something like that sort of vague nonsense.

As you said, the IMPLICATION is that it is a "1 G" car.

If a car accelerates at 1G doing a 1/4 mile, it would get there in just over 9 seconds. The Lexus SC ($65,000 sport coupe) claims to need 14.3 seconds. Even if there is a faster Lexus, the result will not be very close to 9 seconds.

Here's a little physics puzzle/riddle for you: How do cars accelerate faster than 1 G when we have all been taught that the coefficient of friction for surfaces varies from 0 to 1, and friction = weight * coefficient of friction, so by the standard model, you can't get more frictional force than the weight of an object. This means that the tires of a car should never be able to push harder than the weight of a car, which means that it should never be able to accelerate at more than 1 G. Of course we know that plenty of drag racers do it a lot faster than 1 G which would equal a 9 sec 1/4 mile. So, how do they do it?



Simple. Static friction in a rubber/asphalt combination is higher than a coefficient of 1 due to molecular interaction. Heat the tires a bit and the cf goes up higher. Now add downforce from an airfoil perched above those tires so the vertical loading increases with speed and you end up with a car that can accelerate at much higher than 1 G. In fact, a lot of drag cars don't reach maximum Gs until well past the start lights. Notice how they "back pedal" the throttle for the first part of the race?
Exceeding 1 G is common on dirt tracks as well. The sprint cars I raced carried a 25 square foot wing on top and a 6 sq.ft. on the nose. Combined with a tire that worked in the traction medium (moist clay) and 1G acceleration was easy...and a hell of a lot of fun! :)

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distance = Vinitial + acceleration of Gravity

4000ft = zero + 1/2 32ft/s^2 * t^2

4000ft = 16ft/s^2 * t^2

4000/16 * s^2 = t^2

250 s^2 = t^2

15.8 s = t free fall time.

Of course, remember that the engine will make the car "nose heavy", so the air resistance picture will be different from that of a flat car. The car is going "no lift" ;) However, this is our physics-perfect Lexus.

Next -

A car going 60mph covers one mile in 60s.
So to cover a mile in 15 sec, it would have to go 240mph average velocity.

We are not going a mile, just 3/4. 4000/5280 = .75 miles.

So, we can go 3/4 of that speed or .75 * 240 = 180.

End result? Get a running start of 180mph to cross the starting line and keep it there. You'll beat the falling car by a healthy .8 seconds.

All that said? John has been waiting to see if anyone answers this. :D So, hopefully, he'll correct my math and forgive me for not using meters.
:)

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distance = Vinitial + acceleration of Gravity

4000ft = zero + 1/2 32ft/s^2 * t^2

4000ft = 16ft/s^2 * t^2

4000/16 * s^2 = t^2

250 s^2 = t^2

15.8 s = t free fall time.

Of course, remember that the engine will make the car "nose heavy", so the air resistance picture will be different from that of a flat car. The car is going "no lift" Wink However, this is our physics-perfect Lexus.
distance = Vinitial + acceleration of Gravity

4000ft = zero + 1/2 32ft/s^2 * t^2

4000ft = 16ft/s^2 * t^2

4000/16 * s^2 = t^2

250 s^2 = t^2

15.8 s = t free fall time.



Happythoughts,

You didn't consider that the falling car would reach terminal velocity.

The falling object will not continue to accellerate all the way to the ground. The accell rate will start at 32 f/s and then decrease until it reaches 0, i.e. terminal velocity. If the car fell from 4K in a vacuum it would accellerate all the way to the ground, taking 15.8 sec, and the velocity at impact would be ~500 MPH. It actually takes ~5 sec. (can't remembe exactly - i'm drunk) to reach terminal after 350 or so feet. After that its another 3600 ft or so at 125 mph (180f/s) or so. Total time is closer to 25 sec.

The car still loses though, but with a bit less margin.

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Of course, remember that the engine will make the car "nose heavy", so the air resistance picture will be different from that of a flat car. The car is going "no lift" Wink However, this is our physics-perfect Lexus.



Yeah, the orientation of the car would have a significant impact on the term. vel. I'd love to know how they would stabilize something like that. Maybe RC ?

"Once we got to the point where twenty/something's needed a place on the corner that changed the oil in their cars we were doomed . . ."
-NickDG

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Yeah, the orientation of the car would have a significant impact on the term. vel. I'd love to know how they would stabilize something like that. Maybe RC ?



In the Joe Jennings video, they took off a variety of stuff for safety reasons. Windshield, gas tank, motor.
(Without re-watching the video) It seems like the underside had a panel on it also.

That said, it still flipped all over the place and whacked into a cameraman in the process.

Cars just aren't that stable in freefall.

I agree about hitting some type of terminal velocity though. That is true. If anyone times the freefall of the car, post it and we can at least get an average velocity.

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Happythoughts,

So in the Jennings video they kinda AFF'd it? Gotta see that. Sounds difficult and a bit dangerous. Gota see that.

jim

"Once we got to the point where twenty/something's needed a place on the corner that changed the oil in their cars we were doomed . . ."
-NickDG

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Just about everything they've thrown out the back of the Skyvan tends to track in some direction. Cars move pretty strongly but tend to oscillate so much that they don't go in any one direction for very long. One snowmobile got nose-down and started tracking like crazy. Almost took out some cows in the landing area.

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I saw a Toyota commercial yesterday that involved the Loch Ness Monster. I hardly think it worth debating whether or not the paleontological details were correct.

It's a commercial, for goodness sake. Made by professional, highly paid liars.
...

The only sure way to survive a canopy collision is not to have one.

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>can someone please find this video and post it here please i cant
>find it anywhere

I think the only video that exists of the impact is Mike Burrill's, and he hasn't posted it anywhere.



If you carefully look at the video quade posted, frame by frame, you can see that the car actually bounces.

ltdiver

Don't tell me the sky's the limit when there are footprints on the moon

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>can someone please find this video and post it here please i cant
>find it anywhere

I think the only video that exists of the impact is Mike Burrill's, and he hasn't posted it anywhere.



If you carefully look at the video quade posted, frame by frame, you can see that the car actually bounces.

ltdiver



That would be proof that the video doesn't show a car landing after a 4000 ft freefall. Even if it did bounce a little, it would be flattened first.
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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>can someone please find this video and post it here please i cant
>find it anywhere

I think the only video that exists of the impact is Mike Burrill's, and he hasn't posted it anywhere.



If you carefully look at the video quade posted, frame by frame, you can see that the car actually bounces.

ltdiver



That would be proof that the video doesn't show a car landing after a 4000 ft freefall. Even if it did bounce a little, it would be flattened first.



Well, okay...the car parts go everywhere, but you can see the tire lift off the ground just a bit (underneath and behind the driven car). The flattened car (behind) does not rise back up itself. :P

ltdiver

Don't tell me the sky's the limit when there are footprints on the moon

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>can someone please find this video and post it here please i cant
>find it anywhere

I think the only video that exists of the impact is Mike Burrill's, and he hasn't posted it anywhere.



If you carefully look at the video quade posted, frame by frame, you can see that the car actually bounces.

ltdiver



That would be proof that the video doesn't show a car landing after a 4000 ft freefall. Even if it did bounce a little, it would be flattened first.



I think the fact that they spotted it so well proves they didn't drop it from 4k

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"Beware how you take away hope from another human being."
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It's a commercial, for goodness sake. Made by professional, highly paid liars.



true, but that doesn't negate the question of "is this even feasible" (as a stunt)
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Those who fail to learn from the past are simply Doomed.

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It seemed that on Jenning's video the Camera fliers were staying with the cars easily.



Not as easily as the one car that was chasing Olav and hit him in freefall. D'oh!:P
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