Not sure I understand the question. You’re in a seatbelt, while the rocks are able to move freely throughout the interior of the car. They’ll fly throughout the interior in the event of a crash. Even worse, if they are between you and the airbag when it’s deploying, they’ll be embedded into your skull.
I’m not making this up, you can find the same advice everywhere. It’s very dangerous for you and other passengers.
YiddishMcSquidish@lemmy.today 1 day ago
I’m asking why you think rocks that are in front of me would be a risk.
FooBarrington@lemmy.world 1 day ago
Because, again, they will turn into projectiles during a crash. Do you think they’ll just magically stay in their place? They’ll fly around and inflict damage upon passengers, possibly also people outside the car. Please, just look it up if you don’t believe me. It’s very common safety advice.
rumba@lemmy.zip 1 day ago
The rocks are in the same frame of references the passengers. The only difference is they’re not seat belted in so there is room for some small differences in acceleration.
If your car is doing 50 the rocks are doing 50 and then do have a fair amount of inertia compared to the outside world, but everything in the car has that same inertia. That two-ton automobile is the actual danger.
Absolute worst case those rocks aren’t seeing any more than a couple of G, let’s say you max out at around 3G which would be a little bit intense for car related escapades. The rock hitting you in the backseat would be like maybe it falling a dozen feet and landing on you absolute worst case.
Now, if you didn’t have a windscreen, and you hit a stone wall that stopped you immediately The rocks would have a 50 mph variance to the wall. But, honestly, 50 mph on a rock is not really significant. Baseball pitchers double that.
You could try to argue that hitting another oncoming car would give them a 100 mph variance. But at that point the rocks aren’t the problem the hundred mile an hour variance between the two multi-ton cars is more than enough.
The old wise tale that putting things on your dash turn them into dangerous high speed projectiles is false.
I think if you were looking for a solid argument of them being a bad idea, they will easily roll off your dash, get under your feet and would have a much better chance of interfering with your pedals.
coolcat1711@lemmy.dbzer0.com 1 day ago
In a crash, the car, you and anything else are all separate objects. Crash designers attempt to couple you to the car via your seatbelt and airbag. Rocks are free-floating.
When you crash, the car experiences a sudden deceleration. You’re moving forward and the rocks are moving forward. The rocks will move forward until they hit the windshield and then they will bounce. They will also receive some of the energy experienced by the car’s deceleration - which is MASSIVE relative to the mass of a rock.
Depending on the size of the rocks and the speed of the crash, those rocks very well may become bullets. Especially due to their high velocity and potentially small surface area.
I feel like some person genuinely attempting to look out for the safety of someone else and being lambasted for it is wild. Follow the advice if you wish but it’s not like this is uncharted territory. Automotive engineers have been mapping crash dynamics for literal decades…
FooBarrington@lemmy.world 1 day ago
Why don’t you get a couple rocks thrown at your face with 50mph and get back to me?
YiddishMcSquidish@lemmy.today 1 day ago
Bro, I am so not trying to sound argumentative. But please think about the plausibility of that happening. Like I seriously begging you! Even in this weird universe where smaller than a fist sized rocks could cause harm to another object while they are in a semi equal inertial state.
Even then, the windshield(which is sloped downward) would deflect said rocks into a downward direction.
So I’m asking you one more time, what is the danger of having cool rocks on my dashboard‽
FooBarrington@lemmy.world 1 day ago
My god you’re dense. Fine, do whatever you want, I don’t care.
the_tab_key@lemmy.world 1 day ago
I have to imagine that in any scenario where the rocks would be dangerous would also mean that you are fucked anyway.