Split Thread The validity of classical physics (split from: DWFTTW)

[RossFW]

ETA:- PREDICTION- NEXT HUMBERISM:- What has that got to do with the cart?

Where does it suggest that you spin a car's wheels, it is like it is moving?

Close enough!!! I'm Physic!!! Where do I get an MDC application???

 

[RossFW]

Where does it say that spinning a car's wheels is like it is moving?

1st year High School Physics.

 

[humber]

Close enough!!! I'm Physic!!! Where do I get an MDC application???

No, where do any of the suporting videos suggest that spinning a car's wheels is like it is moving?
Sounds like something a highschool student would regard as ridiculous.
Might get a laugh.

Can you get a flat tyre?
What about a unicycle? Does that go at windspeed on the belt?
What if you turn the car on its roof, and put the treadmill on top of the wheels?
ETA:
Improbability index rising.

 

[RossFW]

we will then be subject to a tirade of meaningless blather...........

No, where do any of the suporting videos suggest that spinning a car's wheels is like it is moving?
Sounds like something a highschool student would regard as ridiculous.
Might get a laugh.

Can you get a flat tyre?
What about a unicycle? Does that go at windspeed on the belt?

I'm batting 1000!! Look out Silvia, here I come!!! (I'll donate some of the $1000000 to the Humber Educational Foundation, of course!!)

 

[humber]

1st year High School Physics.

I don't think so.

 

[humber]

I'm batting 1000!! Look out Silvia, here I come!!! (I'll donate some of the $1000000 to the Humber Educational Foundation, of course!!)

Why won't it work upside down? Why not? All the velocities are OK.

 

[spacediver]

You are telling be something that every baseball player knows. When trying to catch a fast ball, move your hand back with the ball, so as to reduce the impact.

Very good. You've learned something from this thread. Earlier, you were insistent that a bullet fired from a train would have an absolute kinetic energy, but now you understand it's relative.

Not bullets. Where does it suggest that you spin a car's wheels, it is like it is moving?

when did i say the video has anything to do with spinning car wheels? It may indeed have something to do with it, but I was just focused on the idea of relative kinetic energy.

As for spinning vs moving wheels, nobody claimed they're the same. You are the one who assumed that a parked car on a moving treadmill has spinning wheels.

 

[humber]

Very good. You've learned something from this thread. Earlier, you were insistent that a bullet fired from a train would have an absolute kinetic energy, but now you understand it's relative.

Show me. I said that zero KE had no meaning, but not that things were not relative.

when did i say the video has anything to do with spinning car wheels? It may indeed have something to do with it, but I was just focused on the idea of relative kinetic energy.

Perhaps, but they still gave no suggestion of anything like that.

As for spinning vs moving wheels, nobody claimed they're the same. You are the one who assumed that a parked car on a moving treadmill has spinning wheels.

What else happens? It must be the spinning. If a cart can do it, why not a car?

 

[RossFW]

Why won't it work upside down? Why not? All the velocities are OK.

You mean in the Southern Hemisphere? As you contend velocities and therefore distances are absolute, being on the other side of the world WOULD be upside down by your logic.

And yes, it would work just fine.....

 

[humber]

You mean in the Southern Hemisphere? As you contend velocities and therefore distances are absolute, being on the other side of the world WOULD be upside down by your logic.

And yes, it would work just fine.....

No more implausible than an Fi car that cab do 300kph when standing still.

I meant if I turn the car upside down, and then drive the wheels with a belt, would that work?
What about a military tank? That's got "treadmills" as wheels.

ETA:
I think that the idea of relative velocities is being misused. I can't believe that I must first be told that an object is moving at windspeed. I usually know when things are moving.
ETA2:
If moving up the belt is going faster, what is the equivalent of distance?
ETA3:
On that topic, if the cart is stationary at the bottom of the belt, is that slower or faster than when at top of the belt?

 

[CNY_Dave]

Guys, how can the treadmill be like the open air test when the cart has no KE when it's on the treadmill?





GAHHH, He's in my HEAD!!!

Please disregard.


I think you can get a Humber Head Explosion if you start talking about the old trick of driving a car up a ramp and into the back of a moving tractor-trailer...


Dave

 

[humber]

Guys, how can the treadmill be like the open air test when the cart has no KE when it's on the treadmill?





GAHHH, He's in my HEAD!!!

Please disregard.


I think you can get a Humber Head Explosion if you start talking about the old trick of driving a car up a ramp and into the back of a moving tractor-trailer...


Dave

That's no problem. The car has an engine. Why can't it climb a ramp moving ahead of it. A bit like a short steep hill, really.
Good question about the KE, though. It does look like a you may expect a small hovercraft to look.
For someone who knows nothing, my description was quite accurate, don't you think? I worked out that friction was involved, and that it would be unstable.All from observing the video and thinking about it. Not bad eh? I have noticed that not one of my claims has been refuted.
When I ask, I am told I know nothing and everybody thinks otherwise.
Always the same answer, not matter what the question. Sounds like I am being handled.

ETA:
On the other thread, they are talking about flywheels. That's madness, or so I was told.

 

[spacediver]

Show me. I said that zero KE had no meaning, but not that things were not relative.

zero KE has meaning. It means that the object in question has zero kinetic energy, i.e. its mass times the square of its velocity is ZERO. This is just as meaningful as saying it has 200 newtons.

What else happens? It must be the spinning. If a cart can do it, why not a car?

huh? I'm not sure you actually carefully read the original question that was posed to you. A parked car or a parked cart does NOT have spinning wheels.

The wheels might spin if you accelerate the treadmill and the friction between the wheels and the belt is low enough. But we're not talking about that. We're talking about a treadmill that is ALREADY in motion at a constant velocity, and a PARKED car on this treadmill.

 

[Modified]

What if you turn the car on its roof, and put the treadmill on top of the wheels?

What's your point? That would be equivalent to placing the car upside down on top of a semi trailer moving at wind speed and driving under a surface that touched the wheels with the same amount of pressure as the treadmill in your example. Of course, the wind won't be much of a factor in the car's performance in those situations.

 

[Clive]

The direction of the wind is not so important as its presence in each case.
The headwind is the major application of the BMW/F1 system, so I used that. So, the answer is, a 10mph wind is met by a 10mph belt in the opposite direction to that wind in each case.
So a tail wind is met by the same. In fact like the condition assumed to exist on the treadmill. That is not the reason that I say it is "backwards". That condition occurs because there is no real tailwind. If there were, then the treadmill would be OK.

Sorry humber, but when I try to parse what you've written, once again I'm left with doubts that I am following your train of thought properly. Can you please clarify this as below.

Let's say you are the operator of the tunnel. You've setting up a test of the cart going directly downwind in a 10 mph wind. You need to enter two values into the computer. The first value set the belt speed relative to the cart, and the second value sets the wind speed relative to the cart (i.e. the speed the air will be moving through the tunnel). In both cases, a positive value means the belt/wind is moving in the same direction the cart is facing (as you see it from inside a booth a short distance to the side of the cart), and a negative value means the opposite direction (from the front of the cart towards its rear). All I need are those two numbers. The computer does NOT understand anything other than numeric values (mph).

If I was the operator, I would input -10 and 0 as below.

Speed of belt under the cart: -10
Speed of air past the cart: 0

What are your inputs?

Speed of belt under the cart: ?
Speed of air past the cart: ?

 

[humber]

zero KE has meaning. It means that the object in question has zero kinetic energy, i.e. its mass times the square of its velocity is ZERO. This is just as meaningful as saying it has 200 newtons.

No it's like two batteries in parallel. If the voltage is exactly the same, no current flows. It's the same with velocities, except that no energy can be exchanged. The room I am in, has lots of things that have 0 relative KE. Most things really. Houses and trees etc. Usually, it's the things with KE that do stuff, or move.

huh? I'm not sure you actually carefully read the original question that was posed to you. A parked car orit a parked cart does NOT have spinning wheels.

Parked? The original question I posed was essentially this.( I ignore attempts to rephrase my questions, if that is what you mean)

If you go outside to your car and place a running belt under the chassis, do you see the car as traveling at belt speed?
Then same thing, but with the wheels on their belt?
Why?

Ah.. Spinning means turning , not slipping. That is what happens when the questions are second hand or assumptions made.
[/QUOTE
The wheels might spin if you accelerate the treadmill and the friction between the wheels and the belt is low enough. But we're not talking about that. We're talking about a treadmill that is ALREADY in motion at a constant velocity, and a PARKED car on this treadmill.

No I meant what is the difference if the treadmill turns the wheels or not.
Looks like magic to me.

 

[humber]

What's your point? That would be equivalent to placing the car upside down on top of a semi trailer moving at wind speed and driving under a surface that touched the wheels with the same amount of pressure as the treadmill in your example. Of course, the wind won't be much of a factor in the car's performance in those situations.

What if the car is on its side?

 

[spacediver]

No it's like two batteries in parallel. If the voltage is exactly the same, no current flows. It's the same with velocities, except that no energy can be exchanged. The room I am in, has lots of things that have 0 relative KE. Most things really. Houses and trees etc. Usually, it's the things with KE that do stuff, or move.

Are you saying that the sentence: "zero voltage" has no meaning? Do you even understand what "meaning" means?

Parked? The original question I posed was essentially this.( I ignore attempts to rephrase my questions, if that is what you mean)

If you go outside to your car and place a running belt under the chassis, do you see the car as traveling at belt speed?
Then same thing, but with the wheels on their belt?
Why?

let's review:

A car parked on a moving belt is exactly the same as a car parked on the road in the wind.

But you agree that the only apparent difference, is that on one case the wheels spin, and in another they do not?

Humber: NO we do NOT agree that in one case the wheels spin. The wheels do not spin in EITHER case.

 

[humber]

Sorry humber, but when I try to parse what you've written, once again I'm left with doubts that I am following your train of thought properly. Can you please clarify this as below.

Let's say you are the operator of the tunnel. You've setting up a test of the cart going directly downwind in a 10 mph wind. You need to enter two values into the computer. The first value set the belt speed relative to the cart, and the second value sets the wind speed relative to the cart (i.e. the speed the air will be moving through the tunnel). In both cases, a positive value means the belt/wind is moving in the same direction the cart is facing (as you see it from inside a booth a short distance to the side of the cart), and a negative value means the opposite direction (from the front of the cart towards its rear). All I need are those two numbers. The computer does NOT understand anything other than numeric values (mph).

If I was the operator, I would input -10 and 0 as below.

Speed of belt under the cart: -10
Speed of air past the cart: 0

That is like the treadmill. with a belt speed of -10. (as seen, really)
This is not valid, there is no wind. It is the equivalent of motion at 10mph, in a vacuum.

Speed of belt under the cart: -10 (nose to prop)
Speed of air past the cart: 10 (prop to nose)

Now that is OK. That is a cart in 10mph tailwind.

The wind and belt are not actually related. If the car were to move in a vacuum, that would not change the way the road passes under the car.
If the wind blows, that does not change it either. The belt is set to move in the opposite direction to travel, but the wind can be either way.

I can't understand why it is believed that turning the wheels equates with motion of the vehicle. The wheels are turning, but there is no motion of the vehicle. That means nothing. Like a fairground amusement.
Yes, books will say this and that about equivalency, but I defy anyone to give me an example where it allows for motion without displacement. That's simply not possible. You can't have linear travel, without covering ground.
The remaining problems are largely due to the effects of trying to support that. A windless windtunnel. No way.

 

[Clive]

If you go outside to your car and place a running belt under the chassis, do you see the car as traveling at belt speed?
Then same thing, but with the wheels on their belt?
Why?

For an observer standing still on the belt (in other words, at rest in a frame of reference that is moving at the same velocity as the belt), the car is observed to be moving in both cases. Depending on the actual direction of the belt movement and your position and orientation on it, you may see the car moving directly towards you and finally impacting your shins in a very painful fashion. If the air is not moving relative to the car body while this is going on, then you will also feel a headwind.

In other words, from a frame of reference that is moving with the belt, the car is seen to be moving (and so also your house and the road and trees beside it and so on). We have put ourselves into a different frame of reference, where positions of things are now measured relative to some origin that is moving at the same velocity as the belt. The origin of our x-y-z coordinate system could be co-located with an X marked on the belt between our feet for example. Velocities of all objects in this reference frame are determine from the rate of change of their position with time (position measured in the same reference frame). Acceleration is the rate of change of velocity with time.

Of course, you can also use a frame of reference that is at rest with respect to the road the car is parked on if you wish. For an observer at rest in that reference frame, the car appears to be at rest. Thus the car can be said to be moving in one reference frame, but at rest in another. The actual values of its position and velocity (and thus also kinetic energy) in each of those different frames of reference will also generally be different. Yet the results of predictions based using on Newtonian mechanics will be the same. The forces will be the same. Mass hasn't changed. Time hasn't changed. And acceleration doesn't change. Try it!