### 8 thoughts on “120mph crash test”

1. uhm hum

so would this be similar to a head on collision with two cars doing 60+?

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• ferdy

Yep…
velocity 60 mph –> bang 120 mph <– velocity 60 mph

Ouch 🙁
Good luck everybody on the streets…

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• Sander

Wrong. See Ozzy’s post below.

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• ferdy

Oups, I didn’t know that… Thanks
I guess I’m just too pessimistic 😀

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2. That’ll leave a mark

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3. Ozzy

Mythbusters did a thing on the 60mph + 60mph and if I remember correctly it still came out to be a 60mph crash.

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• Thy King

Correct. It is the classic error in thinking. When 2 cars crash into each other at 60mph, or ~100km/h, the common believe is that the total crash will be of 120mph or 200km/h severity. This is in total not correct. Each car seperately makes a crash from 100 km/h to 0 (or 60mph to 0). For the occupants of the car, they both experience a crash from 100-0km/h or 60-0 mph (seperately), and not 1 crash of 200 km/h. The difference can be highlighted when you calculate the total kinetic energy in the crash

The formula for energy is E = 0.5 * Mass[kg] * Speed[m/s]^2. Head on 60-60 crash (100km-100km): 2* (0.5 * 1000[kg] * 27.77[m/s]^2). This is significantly smaller than: 0.5 * 1000[kg] * 55.55[m/s]^2.
or: 2* 100-0km/h (60-0mph): 771,6 kJ (kilo Joules)
1* 200-0km/h (120-0mph): 1543,2 kJ
If you read this carefully: 1 crash at 200km/h is 4 times as intense as one crash at 100 km/h!

In other words: this crash test makes nice television, but is otherwise useless.

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4. Kids, don’t try this at home. Try it somewhere else.

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