Hitting a brick wall at 50 vs another car at 50

[Backlash2032]

Mythbusters tested this myth, and they proved that hitting a car that has the exact same mass, exact same speed, exact same everything, is exactly like hitting a solid object at a given speed. That got me thinking.

If car A and car B are the exact same make and model, with the exact same weight, and car A was traveling at 50 mph, and car B was traveling at 100 mph, would it be like hitting a brick wall at 100 mph?

Also, if car A and car B are two different weights. Car A is 2000 pounds (for simplicity sake) and car B is 4000 pounds, and they both collided at 50 mph, would it equal a 100 mph collision for car A?

I think this is actually good basis for Mythbusters to re-visit this myth. I just wanted to check with you guys to make sure im just not stupid with physics... Which i probably am.

 

[hvyman]

If you hit a car and both are going 50mph its like hitting a wall at a 100.

 

[Backlash2032]

If you hit a car and both are going 50mph its like hitting a wall at a 100.

Watch mythbusters, they disproved it with two cars of the same make and model, so same weight.

 

[hvyman]

You have it mixed up.

The damage on each cars colliding is the same as 1 car hitting a wall. The 2 cars hitting each other are still hitting at 100mph. If you add the damage of each car it will equal 1 car hitting a wall at 100.

 

[IJ.]

I watched the same episode and the numbers came out as Backlash stated.

Two cars crashing into each other at 50 mph will result in the same damage (for each car) as a single car hitting a wall at 50 mph.
confirmed

In their small scale tests, the Mythbusters compressed clay at 1x and 2x speeds. Their results showed that two objects hitting each other at 1x speed will cause 1x damage. In their full scale tests, the Mythbusters crashed two cars into a wall at 50 and 100 mph as references. They then had two cars going at 50 mph collide into each other. After surveying the results, it was clear that the two cars suffered damage identical to the car that crashed into the wall at 50 mph. The Mythbusters explained that was possible through Newton’s third law of motion. Although the total force was doubled by having two cars, that force also had to be divided between both cars during the crash.

 

[GrimJack]

Mythbusters tested this myth, and they proved that hitting a car that has the exact same mass, exact same speed, exact same everything, is exactly like hitting a solid object at a given speed. That got me thinking.

If car A and car B are the exact same make and model, with the exact same weight, and car A was traveling at 50 mph, and car B was traveling at 100 mph, would it be like hitting a brick wall at 100 mph?

Also, if car A and car B are two different weights. Car A is 2000 pounds (for simplicity sake) and car B is 4000 pounds, and they both collided at 50 mph, would it equal a 100 mph collision for car A?

I think this is actually good basis for Mythbusters to re-visit this myth. I just wanted to check with you guys to make sure im just not stupid with physics... Which i probably am.

It averages... so car A going 50 and car B going 100 makes for 75 on both cars.

For your second example, it depends on the percentage of weight each car has. Car A takes 1/3 of the damage, Car B takes the rest. There is a total of 100mph, so Car A gets the equivalent of 66.66 mph and Car B gets the rest.

 

[hvyman]

I had it mixed up the first time. Confusing me with the weights and things.

All in all tho its still like getting in a accident at 100mph. Just the damage is split between the cars. Right?

 

[GrimJack]

I had it mixed up the first time. Confusing me with the weights and things.

All in all tho its still like getting in a accident at 100mph. Just the damage is split between the cars. Right?

Nope. It's like getting in an accident at 50mph. The difference is that hitting a wall (well, a wall that doesn't buckle like a cheap tent when 2 tons of steel impacts it at 50mph, anyway) will leave 50 mph of damage on *one* car. Hitting another car head on will leave 50 mph of damage on *two* cars.

 

[hvyman]

Thats crazy.

 

[IJ.]

Always good policy to fact check before posting
(should be lesson #1 when entering Moddom)

 

[hvyman]

Ive been off the last couple days. Had way to much time on my hands. Also i did google it in the process but its still didnt go right in my head.

 

[Backlash2032]

Glad I didnt post this to mythbusters, id feel like an idiot. Thanks guys!

 

[te72]

Makes sense to me, I never really considered that you have another car to absorb damage... then again, I'd love to see a wall that wouldn't collapse if a car hit it at 50mph. That is a LOT of kinetic energy.