Equivalent to: "2 cars colliding head on whilst both travelling at 120 miles per hour"

Ummmm, I`m no physics professor but the force of an object traveling 120MPH into a stationary object is NOT equivalent to the force of two objects traveling 120MPH each head on.

"Ummmm, I`m no physics professor but the force of an object traveling 120MPH into a stationary object is NOT equivalent to the force of two objects traveling 120MPH each head on."

It all depends on the delta (change) in velocity of the car in question.

If the mass of the two cars are roughly the same then both cars will go from 60mph to 0mph (delta-v of 60mph) ending in a tangled mess of metal at rest and you would be correct. If however you have a Ford Focus going at 60mph running into a cement truck going at 60mph in the opposite direction... due to the differences in mass the cement truck would win out and the tiny focus would go from 60mph to maybe -45mph (negative for reversal of direction) leading to a delta-v of 105mph. The end result would be similar to the video above.

To get even closer to the intended result you would want to compare a Focus to a freight train.

TLDR: No, not the same as two cars crashing at 60mph head on.

F*cking terrifying. This is why I don`t drive, and I hate riding in cars for that matter... I wish people took driving more seriously. Maybe after they had been to as many funerals as I have for people killed in car accidents they would think differently. Or not.

Sorry to be a bummer... on a lighter note: I just realized I`m going to be that crazy old lady who walks everywhere and yells at the young kids for driving too fast. *shakes fist in air* Hehe.

@dingdingdong That is untrue. Newton`s third law, for every action there is an equal and opposite reaction disproves that. If you still don`t believe it. Mythbusters

@dingdingdong no that`s wrong. actually when two cars going the same speed hit each other, it`s the same as 1 car hitting a wall at half the speed. here`s a link for proof, brought to you by the mythbusters. http://dsc.discovery.com/videos/mythbusters-mythssion-control/ Watch the "crash force high speed" video (the 6th video down) and the "100 MPH Crash" video (the last video on the list)

So that being said, the video on IAB will be equivalent to two cars traveling at 240 MPH in a head on crash.

Hey nerds! Can`t you just enjoy watching the crash without popping your intelectual zits by disecting the video for it`s Newtonian accuracy?

Lighten up.

Physics is part of the enjoyment, if you understand it. Any idiot can enjoy destruction without having any idea what`s going on. It takes a better educated idiot to gain additional enjoyment from having some understanding of it.

In short, what you see as a detraction because you don`t understand it is an addition to those who do understand it. The lack is in you, not them.

The issue of 120/240 all deals with how much force each body absorbs. If a car is travelling at 120 m/s and a wall is travelling at -120 m/s, when they hit, the car receives an impact as if it were travelling 240 m/s. In the case of two identical cars, one travelling 120 m/s and the other travelling -120 m/s, when they impact, they each absorb half of the total force of impact, and so each is damaged as if they hit a wall at 120 m/s.

Forgive the stupid question, but force is equal to mass x acceleration right? So does that mean there is technically no measurable force on the wall because it doesn`t change speed? How does that work?

Forgive the stupid question, but force is equal to mass x acceleration right? So does that mean there is technically no measurable force on the wall because it doesn`t change speed? How does that work?

It`s not a stupid question. It`s a good question. Here`s my take on it:

i) The force on the wall is equal to the force on the object hitting it. Newton`s third law. Newtonian physics is an approximation, but at these speeds it`s an extremely accurate one.

ii) If the wall is attached securely enough for it to not break, it is in effect part of the Earth. The mass is therefore extremely high, so the acceleration is negligable.

Forgive the stupid question, but force is equal to mass x acceleration right? So does that mean there is technically no measurable force on the wall because it doesn`t change speed? How does that work?

Technically, the wall DOES accelerate. However, since it is effectively part of the earth, the acceleration is imparted to the entire earth. So your equation F = ma, or F/m = a, if you have a very large m (~6 x 10^24 kg) you end up with a very small a.

Next time, give me the car, and I`ll tell you what would happen.

Uhhhh...anyone else catch the error in their math? If a car hits a wall at 120mph, that DOESN`T mean you are simulating TWO cars hitting head-on at 120mph each, as they suggested in the first few seconds of the video. Each car should be simulated going 60mph hence, the same as 1 car hitting a stationary wall at 120.

Forgive the stupid question, but force is equal to mass x acceleration right? So does that mean there is technically no measurable force on the wall because it doesn`t change speed? How does that work?

Technically, the wall DOES accelerate. However, since it is effectively part of the earth, the acceleration is imparted to the entire earth. So in your equation F = ma, or F/m = a, if you have a very large m (~6 x 10^24 kg) you end up with a very small a. A quick calculation shows that at the moment of impact, the earth sped up by ~6 x 10^21 m/s

Next time, give me the car, and I`ll tell you what would happen.

Uhhhh...anyone else catch the error in their math? If a car hits a wall at 120mph, that DOESN`T mean you are simulating TWO cars hitting head-on at 120mph each, as they suggested in the first few seconds of the video. Each car should be simulated going 60mph hence, the same as 1 car hitting a stationary wall at 120. Actually, their math is correct. Hitting another car going the same speed is the same as hitting a wall since in either case, your car is stopped cold.

When 2 cars of equal mass collide head-on, you can add the speeds to get the equivalent of hitting a parked car of equal mass. However, a parked car will recoil and absorb half of the energy of the collision. When you hit an immovable object, you absorb ALL the energy.

vegascartman, HolyGod and everyone else claiming that head-on collision of 2 cars traveling at 60 mph is the same as one car hitting a stationary wall at 120 mph: you are wrong. They even tested that on Mythbusters, when will you learn already?

Everyone`s talking about the Mythbusters and the science behind this. When I saw this video I thought about the Mythbusters, too, but about the rocket car sled episode. Where the rocket sled goes into the compact car, and then through it, and there is no compact car left. The front half of this focus was kind of like that.

When a car hits another car head on, both cars come to a full stop in the same way, each car goes from 60mph to 0mph. They explained the reason for the force is the deceleration.

A head on collision between 2 cars would not double the force for each car, rather both cars would experience the force of 0-60 in however many milliseconds.

well, actually, a car going 120 hitting a wall thats not moving would simulate 2 cars going 60 in a H.O.C. 2 cars goinf 120 each hitting would cause the force impact of 240Mph.

no it wouldnt. based on newtons 3rd law, which is that every action has an equal and opposite reaction. so two cars colliding at 120 Mph headon would still be like hitting a non moving wall because of the amount of force they throw forward is equal to what is pushed back. that is why the car stopped after the crash instead of continuing in either direction. 120---> <---120 then <--- 120 120--->

You know what baffles me? When you see some idiot survive a 100 MPH crash, barely unscathed.

Then you see how badly people are...mangled, for lack of a better term in head-on collisions on highways and interstates, just cruising at around 50-60 MPH.

- BAM! You`re dead... But it is in a spectacular way
Ummmm, I`m no physics professor but the force of an object traveling 120MPH into a stationary object is NOT equivalent to the force of two objects traveling 120MPH each head on.

WTF?

please, guys, don`t do it.

Pretty awesome, anyway.

dicky=diseased or unsound

ticker=heart

It all depends on the delta (change) in velocity of the car in question.

If the mass of the two cars are roughly the same then both cars will go from 60mph to 0mph (delta-v of 60mph) ending in a tangled mess of metal at rest and you would be correct. If however you have a Ford Focus going at 60mph running into a cement truck going at 60mph in the opposite direction... due to the differences in mass the cement truck would win out and the tiny focus would go from 60mph to maybe -45mph (negative for reversal of direction) leading to a delta-v of 105mph. The end result would be similar to the video above.

To get even closer to the intended result you would want to compare a Focus to a freight train.

TLDR: No, not the same as two cars crashing at 60mph head on.

Sorry to be a bummer... on a lighter note: I just realized I`m going to be that crazy old lady who walks everywhere and yells at the young kids for driving too fast. *shakes fist in air* Hehe.

So that being said, the video on IAB will be equivalent to two cars traveling at 240 MPH in a head on crash.

A dicky ticker is slang for heart problems..

Hey nerds! Can`t you just enjoy watching the crash without popping your intelectual zits by disecting the video for it`s Newtonian accuracy?

Lighten up.

Lighten up.

Physics is part of the enjoyment, if you understand it. Any idiot can enjoy destruction without having any idea what`s going on. It takes a better educated idiot to gain additional enjoyment from having some understanding of it.

In short, what you see as a detraction because you don`t understand it is an addition to those who do understand it. The lack is in you, not them.

Angilion, is "The Bing Bang Theory" tv show based on your life? Which one are you?

It`s not a stupid question. It`s a good question. Here`s my take on it:

i) The force on the wall is equal to the force on the object hitting it. Newton`s third law. Newtonian physics is an approximation, but at these speeds it`s an extremely accurate one.

ii) If the wall is attached securely enough for it to not break, it is in effect part of the Earth. The mass is therefore extremely high, so the acceleration is negligable.

Technically, the wall DOES accelerate. However, since it is effectively part of the earth, the acceleration is imparted to the entire earth. So your equation F = ma, or F/m = a, if you have a very large m (~6 x 10^24 kg) you end up with a very small a.

Next time, give me the car, and I`ll tell you what would happen.

Technically, the wall DOES accelerate. However, since it is effectively part of the earth, the acceleration is imparted to the entire earth. So in your equation F = ma, or F/m = a, if you have a very large m (~6 x 10^24 kg) you end up with a very small a. A quick calculation shows that at the moment of impact, the earth sped up by ~6 x 10^21 m/s

Next time, give me the car, and I`ll tell you what would happen.

Actually, their math is correct. Hitting another car going the same speed is the same as hitting a wall since in either case, your car is stopped cold.

When 2 cars of equal mass collide head-on, you can add the speeds to get the equivalent of hitting a parked car of equal mass. However, a parked car will recoil and absorb half of the energy of the collision. When you hit an immovable object, you absorb ALL the energy.

inb4 MYTHBUSTERS ISN`T REAL SCIENCE, etc.

You...aren`t so smart, are you? For the brain dead, it explains at the start of the video that it replicates two cars hitting one another head on.

Only an idiot can`t comprehend the purpose of crash tests, wtf is your life supposed to accomplish?

A head on collision between 2 cars would not double the force for each car, rather both cars would experience the force of 0-60 in however many milliseconds.

OMG facts

Then you see how badly people are...mangled, for lack of a better term in head-on collisions on highways and interstates, just cruising at around 50-60 MPH.