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/sci/ - Science & Math

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9004039 No.9004039 [Reply] [Original]

This just crossed my mind, and I want to know what you think.

1: A car collides into another car, both cars are driving 50km/h.
2: One car is driving 100km/h, and crashes into a parked car.

Which is most fatal, and why?

>> No.9004045

>>9004039
If both cars are moving 50km/h, how would they ever crash they would never reach each other

>> No.9004046

1 for a variety of reasons.
they are "equally" dangerous if you replace the car in 2 with a solid wall.

>> No.9004055

>>9004039
I too watched Mythbusters, anon.

>> No.9004056

>>9004055
I've never watched it, no idea if this was tested on it.

>> No.9004063

>>9004045
Le funny xD

>> No.9004068

Neither? Assuming all cars are of similar mass and construction.
In scenario #1 each vehicle is coming to a complete stop from 50km/h. Each car may as well be hitting a brick wall at 50km/h.
In scenario #2 the moving car's energy is being absorbed by the stationary one. This is more like hitting wall that has quite a bit of give.

>> No.9004071

>>9004046
>they are "equally" dangerous if you replace the car in 2 with a solid wall.
Please explain.

>> No.9004082

>>9004039
They're equivalent.
>Transform to the frame of a car, the other car has velocity of 100 km/s

>> No.9004085

>>9004068
To elaborate:
Both card in #1 are decelerating from 50 over the distance of their respective crumple zones.
In #2 the moving car is decelerating from 100 over the distance of both crumple zones. The rate of deceleration is the same for the moving cars in both cases.

>> No.9004088

>>9004056
https://www.youtube.com/watch?v=-W937NM11o8
What it boils down to is, from a pure physics standpoint, the 100 km/hr crash is more dangerous. "It's the stop that kills you", so to speak. Going from 100 to 0 km/hr does more damage (more momentum transfer) than 50 to 0 km/hr.

>> No.9004248

>>9004088
lol 1x definitely won't be halway up

>> No.9004259

>>9004039
The 100kph crash because Galilean relativity and Newtons laws of motion. (NIST's greatest enemies)

Both cars at a 50kph crash experiences a 50kph crash. The car at 100kph crashes at 100kph.

>> No.9004260

>>9004088
>it's the stop that kills you
So if you're sitting in the stopped car in #2, you'll be unharmed because you were already stopped. Makes perfect sense

>> No.9004313

>>9004260
Google "acceleration" and "velocity" Brainlet.

>> No.9004347

>>9004039
>Which is most fatal, and why?
One car and one parked car has a minimum of one drier
Two cars moving has a minimum of two drivers
Mathematically (2V)^2 > 2V^2

>> No.9004352
File: 116 KB, 758x535, 1148550915225.jpg [View same] [iqdb] [saucenao] [google]
9004352

What happens?

>> No.9004364

>>9004039
1. because not all the energy in 2. goes into your car, it goes into moving the parked car

another way to see it is to set the frame of reference on the moving car
this makes the car coming at you (parked or not) move at 100 km/h but only one will move on with you and the other will not

>> No.9004365

>>9004352
They both shatter because Moh's hardness scale is only a diagnostic tool for identifying minerals, and doesn't say anything about material properties. Diamond is very brittle and easy to break.

>> No.9004368

>>9004088

You're not going from 100 to zero brainlet. You're going from 100 down to 50.

>> No.9005559

>>9004259

The second car's momentum does NO extra damage to the first car's 50kph crash? So if I run at 5m/s towards a fired bullet, I'll only feel a 5m/s impact?

>> No.9005568

I'm pretty sure it's exactly the same, all the cars in this situation have another car approaching them at 100km/h from their reference point no?