Can you say . . . .

Re: Can you say . . . .

Postby husson73 » Mon Aug 25, 2014 9:24 am

when you hit the road you slide a lot and a long time (exactly you could even running round and round like a ball and don't ask me how I know :lol: ) on the asphalt and the grip is better on a road or on a track than on the roof of a car ;)
Jean-Pierre CH.
"We shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender" WS Churchill.
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Re: Can you say . . . .

Postby mitsui spy » Mon Aug 25, 2014 1:38 pm

J.P. you're a sceptical lawyer. I'm a romantic physicist (yeah I know that's an oxymoron). Find me an artist. He'll believe. And besides, if this is fake then we can no longer believe anything we see on vid and that would be depressing. I don't believe in God but I DO SO WANT TO BELIEVE that Belarusian bikers can smash into the backs of speeding cars and do mega-cool back flips onto their roofs! :lol: :lol: :lol: :lol: 8-)
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Re: Can you say . . . .

Postby Rubbadub » Tue Aug 26, 2014 8:14 am

amen to that!
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Re: Can you say . . . .

Postby H2Herman » Tue Aug 26, 2014 5:51 pm

husson73 wrote:fake you won't stay on the roof with the speed :mrgreen:

+ 1 :up :up :up :up
LIFE IS AN ILLUSION CAUSED BY A LACK OF ALCOHOL
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Re: Can you say . . . .

Postby mitsui spy » Tue Aug 26, 2014 7:34 pm

Let's say the car is doing 50mph. Let's say the bike is doing 70mph. By the time of impact he is likely to have hit the brakes and scrubbed off say 5mph. This makes it a low relative speed impact at 15mph (65mph - 50mph). As the bike hits you can see the car jolt slightly, this accelerates the car a couple more mph and the decelerates rider just slightly as he flips into the air. Their relative speed is now down to about 10mph (The bike cartwheels at a relative speed to the ground of over 50mph so it looks dramatic). The rider is in a 50mph airstream which further slows him. He flips forward and lands on the angled surface (i.e. not horizontal) near the top of the rear screen and the compression in his legs absorb the remaining small difference in forward speed. Probably not at a dissimilar speed to an gymnast over a vaulting horse. The rider immediately drops his hands to the rear screen and is being braked by this rear facing surface via his arms and legs and also the airstream. When hit from behind drivers tend not to perform emergency stops but brake steadily to a halt. From impact it takes a considerable distance for the whole shaboodle to come to a halt.

If he had landed on middle of the roof I expect he would have slid forward under braking, but he didn't, he landed on his feet on an angled surface with (presumably) footwear on with a grippy surface underneath. The viewer is travelling with the action so the impression is that the rider comes to an instant standstill just after impact but he's actually still travelling forward just as he would if he were sliding along the ground on his arse. As the driver brakes there is controlled retardation, all the rider has to do is keep his balance which is easy to do on all-fours. If he were sliding along the ground he would be at the whims of friction undoubtedly flip and spin.

Granted it's an unlikely occurrence but with 7 billion people on the planet weird shit happens from time to time. It could be fake but the physics of this one isn't as far fetched as it might as first seem.

Why I even care is a different matter though! :D

Shame it wasn't a convertible is all. 8-)
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Re: Can you say . . . .

Postby husson73 » Wed Aug 27, 2014 8:37 am

have fallen at 15 kilometers -ariound 10 miles - when I broke my ankle with my H2A on 2007. And even at this speed I have slide a lot on the road ;) to finish on the rear tyre of a cark which was parked and broke that you know :o
Jean-Pierre CH.
"We shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender" WS Churchill.
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