theoretically, can a common fly stop a moving train?

Question

fly and train heading towards each other at the same speed.
think about the movement of both the fly and the train

Answer 1

A common fly could stop a moving train if the moving train is a very tiny model of equal mass to the fly because they would have equal momentum which cancels out on impact.

Answer 2

Yes, in a couple of ways. When you say, "stop a moving training," the natural question is, "zero velocity with respect to what?" If you say with respect to the fly, then so long as the fly sticks to the train, then the condition is met.

If you say with respect to the earth, then for equal and opposite momentum: mF*vF=mT*vT, where the "subscripts" F is fly, and T is train, the velocity of the fly needs to be vF=(mT*vT)/mF. Now given that high velocities (by the factor of the ratio between the two masses: mF, and mT) do not stop quickly, the fly will quickly become embedded into the train. So long as the matter disperses quickly and evenly in a conical debris field through out the train (dependent on the location and angle of impact, and the molecular composition and distribution of the fly), it is likely that the train can absorb all of the momentum and energy before any piece of the fly exits the train. In theory, it is possible.

Answer 3

What do you mean by a "Common" fly?
And while your clarifiyng that how big is the train? toy or full size?
i think the question is rather patronising as the train HAS to be MOVING for the fly to attempt to stop it in the first place. Why would a fly want to stop a train that wasn`t moving? it would be pointless, Theoretically or not.

Answer 4

A jedi would tell you it's possible fro the fly to use the force to stop the train, if the fly was a jedi of course.
I suppose if it's mind over matter and the fly could think like that, then yes it would be possible.
In real physical terms, the fly will end up a like a little brown splodge on the train's windscreen. Obviously then if the driver uses the windscreen wiper and it spreads all the fly's guts all over the windscreen, then he sprays water to wash it, and makes it worse so he can't see, and then crashes the train, then yes a fly could stop the train then !!!.

Answer 5

No. The fly does not have enough momentum (mass times velocity) to stop the train since it has very much less mass compared to the train.

But if the fly speeds up and we consider the train and fly both rigid bodies that do not deform. Yes it can stop the train if the fly obtains some momentum which is much greater than the momentum of the train.

But in "real" life, this super fly would pierce through the train if it even had enough momentum (which means it must travel very very fast to obtain very very large momentum)

But in the real real life, the fly would be burned by air friction as it speeds up just to obtain this very very large momentum we require.

Answer 6

the fly could stop the train for a fraction of a fraction of a second because in colliding with the train the fly would be forced to change its direction which would mean it would have to stop as the direction would be directly opposite and if the fly is stationary all be it for the shortest amount of time then the train would have to have been stationary at the same time otherwise the fly couldn't have been, purely theoretical but there some logic in it i think

Answer 7

Momentum equals mass by velocity. Kinetic energy is 1/2 momentum by velocity squared. As you can see the mass has a big effect. To do more damage the fly could be doing about .75 light-speed. That way it would punch a hole straight through the train and the resultant escaping energy would probably blow a BIG crater for miles around.

Answer 8

Yes, if the moving train is a Camel train and the fly misses the long eyelashes of the first camel and his the lead camels eyeball causing it to stop and hence the cameltrain. Have you not read Lawrence of Arabia?

Answer 9

think think think think
of course it can of course it can i say
it would take though the fastest fly or probably the fastes thing alive.

due to law of collisions and law of conservation of momentum etc. ones can set up a theoritical experimnet ta which a fly is travelling very very fast. and it collides to a train
then assuming that we know the masses of the train the fly and the speed of the train we can work ou tthe velocity of the fly to do so..
you want after the collision U train final = 0 and then everything becomes clear ...

yes it is huge velocity its is improbalbe not impossible though. this is physics ( i hope that his velocity is not larger than the speed of light though)


{{{a joke what is the first thing tha the fly will see upon impacts]]]]]]]}}}}


its brains. it will see its brains

Answer 10

Its all relative.

The fly would have to be moving at one hell of a speed for its mass to have any effect on a moving train. Or alternatively the train would have to be moving incredibly slow.

there are probably some calculations you could do involving momentum to give you a more accurate answer but you would need a lot of extra information.