ok scientists and ologists explain this one to me then

[securespark]

Yeah, is most noticeable on film. Watched it on Midsomer Murders the other night, Nettle's car wheels did that.

 

[pipme]

Not sure of that, but have you noticed that flat tyres are only flat on the bottom.

Hence the 'rolling radius' ...

 

[Thermo]

both

 

[pipme]

BTW -- Wheel rotates about axle ... also about the contact point on road.

 

[IanDB]

Does that mean that the top part of the track is going at 60 or even faster to maintain the speed?

Yes. If you think about it, the centre of the axle is moving at the same speed as the vehicle, anything rotating around it obviously changes its relative speed depending where it is.

Just to confuse things, the track in contact with the ground is stationary and the tank is moving at 60mph relative to it. The top part of the track has to catch up so will be doing more than 60, so it will be overtaking! The track has to be going at different speeds as you can see it move relative to the tank.

Blimey, where's all this going?

 

[kendor]

get your head around this then, as a tank moves forward at say 60 mph, the bottom of the track is in contact with the road and therefore stationary. Does that mean that the top part of the track is going at 60 or even faster to maintain the speed?

But the Road isn't stationary it's moving! depends on your point of view whether standing at the roadside or upon the tank

 

[Thermo]

ah now you are verging into the theory of relativity (which i just about understand)

 

[Careful_Bodger]

To a stationary observer, standing by the roadside say, watching a vehicle go by at 60mph, will see the bottom of the wheel stationary (as previously asserted). The top of the tyre will have to be moving forward at 2 x 60mph = 120mph.

If you dont like this, just think of a stick touching a fixed point on the ground. If a point half way up moves at velocity V, then the top moves at 2V.

All clear

 

[GRC]

Yeah, is most noticeable on film. Watched it on Midsomer Murders the other night, Nettle's car wheels did that.

Related to the frame rate of the TV/film camera / TV system (PAL/NTSC) in use. More later.

Regards, Graham

 

[planenut]

Now, there must by some theory which relates to the movement of the earth, and whether the vehicle is moving in the same direction as to the rotation of the earth or any other direction,
............at this point it would be hard to say that one rests his case....
....as the case is not resting but moving in relation to the earth........

 

[Thermo]

ive wondered about that since i was a boy. What about a helicopter hovering above the earth then. Surely if it fixs its position on a point in the heavens and stays airborne for 24 hours it will circumnavigate the globe! How bigs the universe? Whats the meaning of life? Why do we grow?

 

[kendor]

ive wondered about that since i was a boy. What about a helicopter hovering above the earth then. Surely if it fixs its position on a point in the heavens and stays airborne for 24 hours it will circumnavigate the globe! How bigs the universe? Whats the meaning of life? Why do we grow?

42

 

[pipme]

Spinning at about a grand or so an hour --- and a free trip around the sun chucked in every year for free --- You have never had it so good !!

 

[kendor]

Spinning at about a grand or so an hour --- and a free trip around the sun chucked in every year for free --- You have never had it so good !!

Wish you hadn't told me that Pip, now i'm feeling really giddy. Stop the world i want to get off!

 

[pipme]

Kendo me old fruit --- sound at times, like you leapt off ages ago.