Bike vs Train?

[Lights_Guy3]

This is purely hypothetical.

My friend and I are arguing about whether or not a motorcycle could derail a train simply from impact.

So let’s speculate... How fast would the bike have to go? I already understand that the speed required is not going to be a speed that the bike can actually attain, but it’s just for fun anyways...

Situation:

Train going 50mph. 400lb motorcycle with 200lb rider hits the engine perpendicular.

Would the rider aim for the trucks?

Any guesses?

 

[Aluisious]

already understand that the speed required is not going to be a speed that the bike can actually attain

Then it's not worth considering.

HAI GUYZ HOW FAST DO I GOTS TO GO IF I WANNA JUMP MY BIKE TO DA MOON KK THX

 

[BigMatt408]

This thread = Fail

 

[Lights_Guy3]

Daaaaaamn


I'm pretty sure I knew better... clearly not

 

[Spec-ECU]

I like how you guys considered the bike and the rider's weight, but not the train's.

Just ask yourself: what would McGyver say?

 

[rumpofsteelskin]

Isn't this just a mass times velocity problem? If the train engine has a mass of X and velocity zero, the force required to displace it will be the mass of the bike/rider times whatever velocity will produce X + 1. If you have specific numbers, plug them in and there's your answer.

 

[moriya]

Then it's not worth considering.

HAI GUYZ HOW FAST DO I GOTS TO GO IF I WANNA JUMP MY BIKE TO DA MOON KK THX

 

[Dionysus]

 

[Razorback]

At least point 5 past lightspeed.

 

[Lights_Guy3]

what would McGyver say?

I think McGyver would aim for the fuel tank in hopes that it goes boom and lifts the train just enough to pop it off the tracks








Or he would do it with a paper clip and chewing gum

 

[Pauly G]

Go throw a watermelon at a moving car. What happens?

 

[SilverSliver]

Isn't this just a mass times velocity problem? If the train engine has a mass of X and velocity zero, the force required to displace it will be the mass of the bike/rider times whatever velocity will produce X + 1. If you have specific numbers, plug them in and there's your answer.

Sort of.

In a perfectly ideal collision, all of the kinetic energy from the moving motorcycle would be transferred to the train as a potential energy increase equivalent to its necessary increase in height to lift up and off the rails.

In other words, (mass train) * (accel. of gravity) * (height increase) = 1/2 * (mass bike) * (velocity bike)^2.

Assuming the train weighs 400,000 lbs and needs to get lifted 6 inches to become derailed, this works out to about 80mph.

Of course, all of this book learnin' ignores a plethora of practical concerns (such as how to hit a train with a motorcycle that's moving straight up at 80mph), but it is an answer. A more realistic scenario would have maybe 5% of the motorcycle's total momentum moving upward, which means it would have to be traveling at about 2000mph, or about mach 2.5. Maybe with a turbo'ed RC51...

 

[Aluisious]

Go throw a watermelon at a moving car. What happens?

Old lady gets ripped off at a fender shop

 

[Aluisious]

Sort of.

In a perfectly ideal collision, all of the kinetic energy from the moving motorcycle would be transferred to the train as a potential energy increase equivalent to its necessary increase in height to lift up and off the rails.

In other words, (mass train) * (accel. of gravity) * (height increase) = 1/2 * (mass bike) * (velocity bike)^2.

Assuming the train weighs 400,000 lbs and needs to get lifted 6 inches to become derailed, this works out to about 80mph.

Of course, all of this book learnin' ignores a plethora of practical concerns (such as how to hit a train with a motorcycle that's moving straight up at 80mph), but it is an answer. A more realistic scenario would have maybe 5% of the motorcycle's total momentum moving upward, which means it would have to be traveling at about 2000mph, or about mach 2.5. Maybe with a turbo'ed RC51...

WRONG

You can't convert kinetic energy into kinetic energy. Nothing works that way in a crash. Things deform, things get hot, noise is made.

Momentum is conserved, not kinetic energy.

 

[SilverSliver]

WRONG

You can't convert kinetic energy into kinetic energy. Nothing works that way in a crash. Things deform, things get hot, noise is made.

Momentum is conserved, not kinetic energy.

[Inescapable brilliance]

...

In a perfectly ideal collision

...

[Indubitable genius]

WRONG^2, smarty-pants.

 

[V4]

Go throw a watermelon at a moving car. What happens?

in Oakland, the drive-by shooters will stop and have a picnic...?

 

[Karbon]

four words.

rail gun propelled motorcycle

 

[Just J]

This guy said it best:

"Crack is one helluva drug"

 

[Z3n]

Have you seen torque?

Obviously not.

 

[Valgar]

WHAT IF THE TRAIN TURNED INTO A FLAMING DEATH BUS AND JUMPED OVER THE MOTORCYCLE?!?