The fly and the train

[arod]

A fly and a train approach each other at velocities of 50mph, 0 degrees and 50mph, 180 degrees. If the fly stops the train stops, but we know the train doesn't stop; yet it appears the fly must decelerate to a velocity of zero relative to the earth at the time of impact or thereabouts.

Your mission, should you decide to accept it: resolve the patent contradiction.

************************

Some of you may remember me posting this at Newsmax. I respectfully request that you - and anyone else who knows the answer - keep quiet for a few days to give anyone interested a chance to puzzle it out for themselves.

[Unca Walt]

A fly and a train approach each other at velocities of 50mph, 0 degrees and 50mph, 180 degrees. If the fly stops the train stops, but we know the train doesn't stop; yet it appears the fly must decelerate to a velocity of zero relative to the earth at the time of impact or thereabouts.

Your mission, should you decide to accept it: resolve the patent contradiction.

************************

Some of you may remember me posting this at Newsmax. I respectfully request that you - and anyone else who knows the answer - keep quiet for a few days to give anyone interested a chance to puzzle it out for themselves.


I am not sure I am bright enough even to unnerstan' the fargin question!

Oney thing I kin think of is when yer sayin' degrees, that lets me think "North Pole". And when the fly goes a bazillionth of a inch, it is no longer at 0 degrees, and therefore the train gots to stop, 'cause the fly can't go nowhere at 0 degrees. I don't really like that answer... mainly 'cause like I sed... I dunno whut the question is really sayin'.

Or else, if the fly be goin' on a 0-degree vector, and the train be onna 180-degree vector... then they's really sorta just chasin' each other round and round -- at the same speed.

But then that don't sound like it really wuz a real problem... and agin I ain't sure I unnerstan' the question.

Of course, we kin start that "upside the haid" shit, and point out that at 0 degrees, the fargin fly would freeze to death and stop... ;) 8)

Unca Walt

[arod]

Or else, if the fly be goin' on a 0-degree vector, and the train be onna 180-degree vector... then they's really sorta just chasin' each other round and round -- at the same speed.

I don't know how one would get that idea exactly...but never mind. Let's put it thisaway, pardner: they's a'comin' straight at each other. Now putcher brain on it. ;)

[Satan]

Y'know what they say, Walt...some days you're the fly, some days you're the train. 8)

[Satan]

I'm probably not going to express this in the correct mathmatical terms, but what the hell...


If the fly stops the train stops,

In what universe?

;D

[arod]

OK, let's hear what you guys came up with. Wrong answers first, please. ;)

[Lazarus]

Are the fly and the train on the same geometric plane or can the fly be flying higher than the train?

"Straight" in a 3-dim or 4-dim universe?

Does the curvature of the earth remove the possibility of impact since the fly might fly beneath the train?

Points to get answers to. ;D

[Satan]

Are the fly and the train on the same geometric plane or can the fly be flying higher than the train?

"Straight" in a 3-dim or 4-dim universe?

Does the curvature of the earth remove the possibility of impact since the fly might fly beneath the train?

Points to get answers to. ;D


[Because I know he has you on 'Ignore'...] ;D

[wellkeptsecrets]

I just stopped in to see the impact. Has it happened yet or am I too late? I've always wondered how a fly looks squished on the front of a train. 8)

[arod]

No "hyperdimensional" BS allowed. The fly and the train collide.

[Ashley]

I’ll take a shot at it.

It seems that velocity is directly related to mass.
Since the fly’s mass is almost insignificant to the mass of the train.
It only appears that the fly velocity slows down to 0.

That is the best that my research could provide.

[Ashley]

I looked op the definitions of speed, velocity, and mass online which how I arrived at this answer.

[arod]

I’ll take a shot at it.

Thanks. Isn't it weird that it sat here all this time and nobody else did? :)

It seems that velocity is directly related to mass.

I don't know where you get that idea. Can't massive objects move quickly and not so massive objects move slowly?

Since the fly’s mass is almost insignificant to the mass of the train.
It only appears that the fly velocity slows down to 0.

I don't see how your conclusion follows from your premise.

That is the best that my research could provide.

I don't think you need to research anything. Try this: pretend that you can observe the fly and the train from, say, the sun. Now how do the fly and the train appear to move in relation to each other?

[jeny]

The real question is whether or not one needs to know this? When will I ever have any real need to know the scientific answer to this question and isn't it just midless drivel? ;D

[arod]

Certainly for those who lack the mental capacity to get their minds around anything more erudite than, for instance, the intricacies of breastfeeding, there is no shame in sticking to what they're comfortable with. 8)

[jeny]

Certainly for those who lack the mental capacity to get their minds around anything more erudite than, for instance, the intricacies of breastfeeding, there is no shame in sticking to what they're comfortable with. 8)


Oh, oh, oh, SO mean. I'm referring to your complaint that alegebra serves no purpose to most people. The same is true of your fly and train problem. ;)

[arod]

Lighten up, Jen. I got your point. I was just having a little fun. ;)

[jeny]

Lighten up, Jen. I got your point. I was just having a little fun. ;)


So was I. FTR, I do not think knowing the solution to this problem is a waste of time.

[Ashley]

Well my first shot missed by a mile!


I don't see how your conclusion follows from your premise.


I’m sorry; I got my facts mixed up.
It was acceleration / deceleration of velocity that was proportional to mass.

This was the reason I stated that the fly only appears to decelerate to a speed of zero compared to the train.
Assuming that the impact has started the chain reaction of deceleration in both bodies, and inertia continues to move both the train and fly.

Well here is my second shot at it!

This is how I see the movement of both bodies if no such chain reaction is started.

The fly’s face will decelerate to zero and his butt will continue at 50 mph, as his butt travels through to his face.
The fly’s face has already changed direction and accelerated to 50 mph. So did the whole fly decelerate to zero? My answer would have to be “No”

You alluded to the idea that I am over thinking the problem. It is highly possible that I am!


I don't think you need to research anything. Try this: pretend that you can observe the fly and the train from, say, the sun. Now how do the fly and the train appear to move in relation to each other?


If fly and train are both on X-axis. The fly is at zero degrees and train is at 180 degrees heading toward each other at 50 mph.
I am a little slow on this, but I don’t understand how changing my position from the Z-axis 90 degrees to Y-axis 90 degrees is going to help me see a difference in the movement of both bodies.

[arod]

Well my first shot missed by a mile!

Well at least you took it. :)

Well here is my second shot at it!

This is how I see the movement of both bodies if no such chain reaction is started.

The fly’s face will decelerate to zero and his butt will continue at 50 mph, as his butt travels through to his face.
The fly’s face has already changed direction and accelerated to 50 mph. So did the whole fly decelerate to zero? My answer would have to be “No”

This is sort of a variation on an answer I was given which involved "action at a distance". However, if ANY part of the fly decelerates to 0 mph, the paradox remains, no?

You alluded to the idea that I am over thinking the problem. It is highly possible that I am!

Yes, it's a lot simpler than you think.

If fly and train are both on X-axis. The fly is at zero degrees and train is at 180 degrees heading toward each other at 50 mph.

Here's a hint: that is true from the perspective of one observing the incident from earth.

I am a little slow on this, but I don’t understand how changing my position from the Z-axis 90 degrees to Y-axis 90 degrees is going to help me see a difference in the movement of both bodies.

Here's another hint: don't think different axis, think different reference frame.

[Unca Walt]

light

[arod]

light

Care to expand on that? :)

[Ashley]

Shot #3
Those are very good hints.
By sun you meant location, like looking back at earth!
The Earth’s rotation is also in play. The velocity of both fly and train never reaches zero.
Unless planet stops and universe stops and so on.
It would be a simple solution.

[arod]

Shot #3
Those are very good hints.
By sun you meant location, like looking back at earth!
The Earth’s rotation is also in play. The velocity of both fly and train never reaches zero.
Unless planet stops and universe stops and so on.
It would be a simple solution.

Well done. :)

It seems there is no such thing in the universe as an object at rest. Agree?

[Ashley]

Agree!
So Newton’s law of motion that states " An object at rest will remain at rest until acted upon by an outside force" could be an incorrect statement.

[FFWBecky]

Holy hell.

Note to self: don't bother with this forum any longer, especially if you are running low on Advil.

:P

[arod]

Agree!
So Newton’s law of motion that states " An object at rest will remain at rest until acted upon by an outside force" could be an incorrect statement.

Good point. It is a true statement within the confines of an inertial reference frame, though.

[Ashley]

It seems that we use descriptions all the time to help us understand things
Example I believe that 1D and 2D don’t really exist in a matter based universe they just help us understand 3D.