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theneedfull t1_j5fagk2 wrote

Reply to comment by GetInZeWagen in You too could save your children for just $1.88 by sadnlonely916

I don't know if I've wrapped my head around the physics of it, but I'm pretty sure that a sudden crash would just swing the baby up into the roof of the car with the same force of the impact. The hammock doesn't really take anything significant off that momentum, it just changes the direction. And I would think the roof of those old cars would be a lot more solid and unforgiving than the back of the seat.

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zonggestsu t1_j5fdn3a wrote

I don't necessarily think the baby would go to the roof, but instead would go 90° from it's resting point to it's direction of movement, which would be that of the vehicle's before it comes to a sudden stop. Of course this also depends on how high the axis of rotation is, where the hammock tied. Another worry would be if the baby would hit the seats in a crash or can the ropes withstand the sudden strain caused by the crash.

Edit: changing wording to explain thought better

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AlJameson64 t1_j5fl1sn wrote

In the simplest physics of a a front-end collision with an immovable object, the baby would go from resting point to 90 degrees at the speed the car was travelling; that's true. However, now the baby has angular momentum equal to that speed, and nothing would stop it rotating at the 90-degree point. If there's enough distance from the anchor points to the roof, it would spin all the way around, repeatedly until air resistance and friction slowed it to a stop. If not? Yeah, it would stop at the roof of the car.

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dasookwat t1_j5g3laq wrote

this would imply a theoretical instant stop situation, where the car it self
and whatever it hits, would not deform. If there's any crumpling of things going on, the car would not stop in an instance, and instead slow down really fast. this compensates for moving over the 90" point depending on how much time it takes for the baby to reach the 90" angle, vs the time it takes the car to stop.

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dasookwat t1_j5g300m wrote

my guess would be, the baby would be the safest person in a frontal impact car crash because the hammock is somewhat stretchy. a frontal impact would move the hammock forward, and stay there long enough to stop going to the roof. but the baby has no real impact injury because there is no travel distance for the baby. Unless ofcourse the hammock is not strong enough. Then there will be a baby sized projectile going through the front window.

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[deleted] t1_j5gotlg wrote

[deleted]

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theneedfull t1_j5gpqes wrote

Think of a punching bag. And you push it crazy hard. Yes, it starts by going forward, but then it swings up. That's what happens here.

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