Wazza Posted November 12, 2008 Posted November 12, 2008 Can I give it a go.....? If you look at the center of the wheel it is travelling at say 120km/h.The outside of the tyre is travelling a hell of a lot faster because if the wheel is rolling, the outside of the tyre passes the center on every rotation. Now, if the tyre comes loose the wheel is spinning at a rate much faster than it was travelling, and on every bounce would accelerate it. Combined with no rolling resistance it could gather speed untill it reaches the speed that the outside of the tyre was travelling at. Sorry if this has been mentioned, but I didn't read the whole thread.
fandacious Posted November 12, 2008 Posted November 12, 2008 Can I give it a go.....? If you look at the center of the wheel it is travelling at say 120km/h.The outside of the tyre is travelling a hell of a lot faster because if the wheel is rolling' date=' the outside of the tyre passes the center on every rotation. Now, if the tyre comes loose the wheel is spinning at a rate much faster than it was travelling, and on every bounce would accelerate it. Combined with no rolling resistance it could gather speed untill it reaches the speed that the outside of the tyre was travelling at. Sorry if this has been mentioned, but I didn't read the whole thread.[/quote'] nope... the surface in contact with the road is travelling @ 120km/h...
Wazza Posted November 12, 2008 Posted November 12, 2008 Can I give it a go.....? If you look at the center of the wheel it is travelling at say 120km/h.The outside of the tyre is travelling a hell of a lot faster because if the wheel is rolling' date=' the outside of the tyre passes the center on every rotation. Now, if the tyre comes loose the wheel is spinning at a rate much faster than it was travelling, and on every bounce would accelerate it. Combined with no rolling resistance it could gather speed untill it reaches the speed that the outside of the tyre was travelling at. Sorry if this has been mentioned, but I didn't read the whole thread.[/quote'] nope... the surface in contact with the road is travelling @ 120km/h... If you paint a little mark on the outside of the wheel and move the center of the wheel 1m forward, the outside of the wheel would travel further? If you move something 1m and the outside travels further, in the same amount of time, then it must go faster, not?
TNT1 Posted November 12, 2008 Posted November 12, 2008 Can I give it a go.....? If you look at the center of the wheel it is travelling at say 120km/h.The outside of the tyre is travelling a hell of a lot faster because if the wheel is rolling' date=' the outside of the tyre passes the center on every rotation. Now, if the tyre comes loose the wheel is spinning at a rate much faster than it was travelling, and on every bounce would accelerate it. Combined with no rolling resistance it could gather speed untill it reaches the speed that the outside of the tyre was travelling at. Sorry if this has been mentioned, but I didn't read the whole thread.[/quote'] nope... the surface in contact with the road is travelling @ 120km/h... If you paint a little mark on the outside of the wheel and move the center of the wheel 1m forward, the outside of the wheel would travel further? If you move something 1m and the outside travels further, in the same amount of time, then it must go faster, not? Nope, same speed.... Ever seen a vinyl record player... the tracks at the inside spin the same speed as the tracks at the outside... otherwise the singer would sound like a chipmunk at the outside and a retard at the inside according to you...
Johan Bornman Posted November 12, 2008 Author Posted November 12, 2008 nope... the surface in contact with the road is travelling @ 120km/h... Funny enough, the surface in contact with the road is travelling at Zero kph with respect to the road. On a moving tank or bulldozer, approximately one third of the track is always stationary with respect to to the ground it is moving over.
fandacious Posted November 12, 2008 Posted November 12, 2008 nope... the surface in contact with the road is travelling @ 120km/h... Funny enough' date=' the surface in contact with the road is travelling at Zero kph with respect to the road. On a moving tank or bulldozer, approximately one third of the track is always stationary with respect to to the ground it is moving over. [/quote'] the surface in contact with the road is travelling @ 120km/h in relation to the trailer body right next to it...
Wazza Posted November 12, 2008 Posted November 12, 2008 nope... the surface in contact with the road is travelling @ 120km/h... Funny enough' date=' the surface in contact with the road is travelling at Zero kph with respect to the road. On a moving tank or bulldozer, approximately one third of the track is always stationary with respect to to the ground it is moving over. [/quote'] the surface in contact with the road is travelling @ 120km/h in relation to the trailer body right next to it... The center of the wheel is travelling at 120km/h in relation to the road, the outer diameter of the tyre is travelling faster.
TNT1 Posted November 12, 2008 Posted November 12, 2008 The center of the wheel is travelling at 120km/h in relation to the road' date=' the outer diameter of the tyre is travelling faster.[/quote'] No! Refer to the record player...
fandacious Posted November 12, 2008 Posted November 12, 2008 The center of the wheel is travelling at 120km/h in relation to the road' date=' the outer diameter of the tyre is travelling faster.[/quote']No! Refer to the record player... bob... RPM != km/h...
Wazza Posted November 12, 2008 Posted November 12, 2008 The center of the wheel is travelling at 120km/h in relation to the road' date=' the outer diameter of the tyre is travelling faster.[/quote']No! Refer to the record player... The record player is not travelling at 120km/h....
TNT1 Posted November 12, 2008 Posted November 12, 2008 I like this wazza weirdo... I'm not letting him set up the cateye on my bike... depending on if he locates the magnet and sensor closer to or further from the rim, I might go faster or slower...
GoLefty!! Posted November 12, 2008 Posted November 12, 2008 Ok heres my take on this. It has to do with relativity. Mnay years ago I as cycling up Wynberg main rd in Cape town. I heard a funny skipping sound behind me I looked around and saw a wheel nut chasing me. As I looked up I saw an old Dodge pickup truck driving past. A few seconds later the rear wheel came away from the axle and angled off into Russells furniture stores shop window, destroying a dinner table and a few mirrors along the way. A hung around incase the police needed witnesses. they took my statement and I said that the wheel had come off and angled off into the store. Now what happened is this. the wheel comes off the axle and possess angular momentum, i.e. it is not balanced along it's centre line since it is designed to work as a pair, one either side. this imbalance and the angular momentum creates precession similar to the funny dance that spinning top does. Hence it takes off away from the vehicle. Also as it comes off the axle the axle actually gives it a slight shove at 90 degrees to the rotation, Newtons 3rd law. the perception of the wheel accelerating is created by a few things. Firstly the vehilce will slow down slightly since the frictional resistance on the remaining wheels has increased, they carry more load now. So the friction force is higher. the wheel is travelling a different path, usually longer but maintains momentum better than the vehicle since it has less drag, and less friction. it does not accelerate any more than it did before, it is just maintaining its momentum better. Now because the wheel was heading toward your friend while the truck was actually heading off at a tangent, it would be perceived that the wheel was accelerating toward the driver while the truck wasn't. It's a matter of where you are observing the event from. If you were sitting in the truck you would see the wheel separate, run alongside and then gradually drop back as it's distance to the truck grows while it is heading tangentially away from the vehicle.
whistler Posted November 12, 2008 Posted November 12, 2008 Don't know if this has been posted yet, but here goes. As soon as the vehicle is left with only 3 wheels, with the end not having a wheel anymore scratches on the ground, it will slow down. Thus, the effect really is that the vehicle slows down and the wheel continues to travel at the same speed. The energy arguments is not incorrect, just bear in mind that the car slows down, not having 4 wheels anymore and getting a lot more friction from the tar on the axle without a wheel. someting like that...
Wazza Posted November 12, 2008 Posted November 12, 2008 Ok TNT. Let's take your example of the record player.On the inside track, the circumference could be say 10cm. That is the ring closest to the center of the record, remember, it's the circumference. Now, if you take the outer most track on your record, the circumference could be about 1m (or 100cm). If you draw a line from the center to the end of the record and spin it once, the line (or points) would end at the start at the same time. One point has travelled 10cm, the other point has travelled 100cm in the same amount of time. Now which one was travelling faster?Enough said.Wazza2008-11-12 03:55:30
MintSauce Posted November 12, 2008 Posted November 12, 2008 The center of the wheel is travelling at 120km/h in relation to the road' date=' the outer diameter of the tyre is travelling faster.[/quote'] No! Refer to the record player... It's all about the music
TNT1 Posted November 12, 2008 Posted November 12, 2008 So, cause I hear the music at the same speed if the needle is in the center or at the edge is due to relative time dilation? OMG... Last time a drop acid and listen to Grand Funk Railroad...
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