The Zeno effect

[threaded]

You mean like Adams and Leverrier using Newtonian mechanics to predict the existence and position of the planet Neptune before it had been observed? Good point.

It is often acclaimed as a great triumph of Newtonian mechanics, but unfortunately that claim is bollox. They both independantly made the same mistakes, and I find that mildly amusing. It is very sad that people have been repeating the mantra, even teaching it in schools and university courses, when it is quite wrong and has been known to be wrong for over 150 years. But these farie tales get a life of their own and stick in popular imagination.

Their calculations got the orbit and size of the planet completely wrong, it was pure luck Neptune just happened to be in the correct direction at the time observations were made. The current model has things slowing at they move further away from the Sun, also the Oort cloud is quite large. These and many other things were not used in their calculations either.

It was a total fluke.

[threaded]

Perhaps you could demonstrate that bogey is stationary for longer than zero seconds.

But that's my point: you have to invoke some voodoo divide by 0 type thing into the model to make the model work for this situation.

[bogeyman]

But that's my point: you have to invoke some voodoo divide by 0 type thing into the model to make the model work for this situation.

Why do you need this 'voodoo divide by 0 type thing"?

Explain what you think happens then.

[Fungus]

The problem only arises if you consider the train and threaded as solid non compressible objects. In practice they both consist of layers of atoms. As the train hits threaded, so atoms compress, the elecstrostatic repulsive forces between them increase, and gradually Threaded is accelerated.

[Jabberwocky]

Very good fungarse, but what if I fire one atom at 200mph at a stationery atom - does the stationery atom suffer infinite acceleration.

[Fungus]

Very good fungarse, but what if I fire one atom at 200mph at a stationery atom - does the stationery atom suffer infinite acceleration.

Who rattled your cage you complete Tosser.

The forces are electrostatic. The mechanics are quantum not classical.

[bogeyman]

The problem only arises if you consider the train and threaded as solid non compressible objects. In practice they both consist of layers of atoms. As the train hits threaded, so atoms compress, the elecstrostatic repulsive forces between them increase, and gradually Threaded is accelerated.

Indeed.

Look at crash test videos where they crash a car into a stationary concrete wall.

Does the car stop at the instant it's bumper contacts the wall? No, of course not. The wall absorbs the energy of the moving car as it rapidly decelerates (crumpling up as it does so).

Now, supposing the same section of concrete wall was on a big forklift truck and trundling towards the crash test car at, say, 5kph- similar to "Bogey and the Train" problem.

A single point on the bonnet of the crash test car will rapidly decelerate, come to a standstill, and accelerate in the reverse direction.

Why? Because the crash test car has mass and velocity. The wall has mass and velocity (maybe zero velocity, but it doesn't matter).

Due to it's far greater mass (and thereby inertia), the wall will win the argument - even though it may shift slightly as it absorbs the kinetic energy from the moving car.

The car will decelerate from its original speed to 0, quite rapidly - but not instantaneously!

[Churchill]

Indeed.

Look at crash test videos where they crash a car into a stationary concrete wall.

Does the car stop at the instant it's bumper contacts the wall? No, of course not. The wall absorbs the energy of the moving car as it rapidly decelerates (crumpling up as it does so).

Now, supposing the same section of concrete wall was on a big forklift truck and trundling towards the crash test car at, say, 5kph- similar to "Bogey and the Train" problem.

A single point on the bonnet of the crash test car will rapidly decelerate, come to a standstill, and accelerate in the reverse direction.

Why? Because the crash test car has mass and velocity. The wall has mass and velocity (maybe zero velocity, but it doesn't matter).

Due to it's far greater mass (and thereby inertia), the wall will win the argument - even though it may shift slightly as it absorbs the kinetic energy from the moving car.

The car will decelerate from its original speed to 0, quite rapidly - but not instantaneously!

Might I refer the learned congregation to ESL? The European Simulation Language based on the Cosby Hay Discontinuities algorithm?

BTW, did I tell you that I ported the original Fortran based Simulation Engine when I was SNOBBUTAYOOT?

Churchill in "Blatant Threaded" mode!

[threaded]

A single point on the bonnet of the crash test car will rapidly decelerate, come to a standstill, and accelerate in the reverse direction.

So, what happens if this single point is right at the very front?

[threaded]

Well, threaded's argument seems to be that, if bogey is stationary, then so is the train.

1. Bogey is only stationary for zero seconds (the point where your graphs cross)

2. Ergo we measure the train for the same period of zero seconds

3. If you measure the velocity of anything for zero seconds, it has not moved, therefore during that time it is stationary (the basis of the stationary bogey argument)

4. Ergo the train is stationary too

This is just as counter-intuitive as your point about your body reversing direction. Perhaps you could demonstrate that bogey is stationary for longer than zero seconds.

My argument is that this is what the model says.

I say there is'nt a precise static instant in time underlying a dynamical physical process at which the relative position of a body in relative motion or a specific physical magnitude would theoretically be precisely determined. There is no such thing as an objectively progressive time. The 'present moment' are derivative notions without actual physical foundation in nature.

Objects do not, and also can not, move in space-time, they exist in space-time.