2007-11-09 04:31:49 · 11 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Insufficient information - but of course the "silly" answer is to say "It's ALWAYS on the road surface, otherwise you'd be flying" ! ! !
2007-11-09 04:46:28 · answer #1 · answered by minefelloff 6 · 0⤊ 1⤋
You've got some good answers above i.e. where they talk about the tyre footprint having zero speed (i.e. does not skid).
I'd just add that if tyre and road were perfectly rigid the stationary point would be infinitesimally small and that point would be stationary only instantaneously.
People who say that no part of the tyre is stationary are clearly wrong. To emphasise this point consider a train wheel with a flange - points on the flange near the bottom actually reverse direction when they're below the wheel/rail contact point.
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2007-11-09 10:30:54 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Unless a tyre is grossly over inflated then there will be a small flat section in contact with the road and the time in which a point of this flat section stays in contact with the road (thus stationary relative to the road) will be the time taken for the vehicle to cover a distance equal to the length of the flat section of tyre.
So if the flat section of tyre is say 50mm and the vehicle is travelling at say 50km/hr work out how long it will take the vehicle to cover 50mm.
2007-11-09 05:01:43 · answer #3 · answered by ashkirkian 3 · 1⤊ 0⤋
Well then the question must also be asked how fast is the tire moving when it touching the surface. You must think of it like a tank track. As the tank rolls over the track the track stays still. Where the 50mph you see on your speedometer is the speed in the center of the tire. There for the tire is moving at 0mph when touching the road so by doing some math you would be able to figure out for what period of time is the tire at 0 mph.
2007-11-09 04:43:00 · answer #4 · answered by planekid271 1 · 1⤊ 0⤋
The bottom of a tyre which is in contact with the road ,is always stationary as it would be skidding if it moved at that time.
The top of the tyre is travelling at twice the vehicles speed .
The centre of the wheel is the only part of the wheel to be traveling at the same speed as the vehicle.
2007-11-09 05:54:50 · answer #5 · answered by philhoonoseitall 6 · 1⤊ 0⤋
A rotating tyre does not actually stop - what you seem to want to find out is how long is any section in contact with the ground for - for this we need to know the speed of rotation of the wheel and its diameter. e.g a wheel rotating at 3000rpm does 50 turns per second. If the circumference of the wheel is 100cm, then each cm of the wheel is in contact with the ground for 1/5000 second (.0002s)
2007-11-09 04:45:21 · answer #6 · answered by Anonymous · 0⤊ 1⤋
Just long enough to make a lasting impression on Hillary's FACE!
4" div. by circum. of tire = x
tire revolution rate per sec. = y
X . Y = ANSWER
2007-11-09 04:51:23 · answer #7 · answered by Elliott J 4 · 0⤊ 1⤋
You would need more information: how fast is the tire spinning, what is the footprint of the tire, what is the circumference of the tire, etc...
2007-11-09 04:40:37 · answer #8 · answered by T 5 · 1⤊ 0⤋
An instance, of course.
2007-11-09 04:37:33 · answer #9 · answered by ironduke8159 7 · 0⤊ 1⤋
if in motion then not at rest so doesn't stop
2007-11-09 04:40:32 · answer #10 · answered by Clint 6 · 0⤊ 1⤋