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# Safety while breastfeeding and riding in the car? - Page 3

Just another point about the slings...

Say you have a 10lb baby in there & are in a 30mph crash, that would mean the sling would have to support 300lbs. I'm thinking with that much force the fabric could either pull loose from the rings or the rings could easily bend/break. Baby would also fly forward & hit the back of the front seat. That would promptly be followed by the adult smooshing the baby. Just typing that out made me nauseated.

I can't see how this can be seen as alarmist when really common sense should win out. Car safety isn't based on opinion. It is based on the laws of physics.
Quote:
 Originally Posted by ThreeBeans Let's say you're a 120 pound woman and you were in a 30 mph crash. That would be THREE THOUSAND SIX HUNDRED pounds of force on your baby should there be an impact.
This doesn't make sense. The units don't work: pounds (mass) x mph does not equal pounds (force).

In order to calculate the force of impact on the baby you need the acceleration of the vehicle. If you go from 30 mph to 0 slowly, there is very little force; hit a wall, and there will be a very large force. You can calculate force = mass x acceleration, where the appropriate units would be newtons = kg x m/s^2 or, in foot/pound units, force-lbs = slugs x ft/s^2 (where a slug is unit of mass defined as 1 force-lb s^2/ft).

/end physics lecture

In any case, the point was a good one. Leaning over the baby in a moving vehicle is dangerous.
Quote:
 Originally Posted by cognito Say you have a 10lb baby in there & are in a 30mph crash, that would mean the sling would have to support 300lbs.
Also not correct, see my post above.
Yes, she was correct. That is how you calculate the pounds of force being exerted on the car seat, or in this case the ring sling. She was absolutely correct: 10 lbs of baby in a 30 mph crash= 300 pounds being exerted.
The car that we had when DD was little was a '78 caprice. Shoulder belts? Hahahaha. So yeah, I could sit forward a little, flop an extra-sized boob over the side, and everyone was happy. I'm not sure whether that is actually less safe for me since shoulder belt was not an option anyway and either way I was slamming face-first into the seat in front of me, yk? Also not sure how much the boob weighed. More than a bottle I'm sure, but less than a whole human being leaning over her. Not an option this time anyway, with two kids in a Jeep, so I don't need to think about it. Guess I'm just sitting home.
Quote:
 Originally Posted by an_aurora Yes, she was correct. That is how you calculate the pounds of force being exerted on the car seat, or in this case the ring sling. She was absolutely correct: 10 lbs of baby in a 30 mph crash= 300 pounds being exerted.
No, I'm sorry, but this is wrong. You cannot multiply pounds x speed and get pounds. Does. Not. Compute. To calculate force you need mass times acceleration, in properly adjusted units.
Fine, I will go dig out my freakin manual to quote it to you.
My mom told me she did this with my brother. We (my parents, younger brother, and I) were all on a car trip. My brother was hungry, but my father would not () stop. So my mom sat on one side of the back seat, my brother in the middle, and me on the other side. She leaned over so he had access to the boob, while she stretched an arm over to play with me/keep me company (I'm 21 months older). This was in the mid 80s, so safety regulations weren't as strict/well known.

I, myself though, have never done it. Not saying I wouldn't if I needed to, but I haven't.
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 Originally Posted by ThreeBeans AAAAAAAAAAAAAAAAAAAAAAAGGGGGGGGGGGGGGGGGGGHHHHH. Don't confuse alarmism with common sense. This stuff is the reason we have to have car seat laws at all
Thje same could be said for hospiptal birth, vaccines and circumsicion. I'm quite capable of weighing the risks vs the benefits for my situation. THere are times when the potentialbenefit of a car seat outweight the immediate risk to baby's emotional well being.

NAK (although not in a car at the moment)
Quote:
 Originally Posted by Ironica No link, but there are crash test videos showing what happens to an adult who is belted into the back seat. They often hit the front seat. It's not too difficult to imagine what would happen to a baby between the adult and the front seat. Replace "car seats" with "c-sections" and see how you feel about the sentence now. :-/ Women DIE from unnecessary surgery. Babies DIE from lack of proper restraint in an accident. That's not alarmism, that's truth.

Exactly - we all have to weigh the risk vs. benefit for our own situation. Babies die from homebirth, too. Babies die while in car seats and while walking down the street. THe sad fact of life is that babies die sometimes.
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 Originally Posted by PassionateWriter i we should all seek to do what is safest, right?
absolutley! But for me, I take into accoutn my baby's emotional as well as physical well-being.
If your manual says that, it's wrong, too. I'm a scientist as well, and have taken physics up to quantum mechanics, so yeah, I'm decent at physics. Force=mass*acceleration, not mass*speed. More will be involved than just simply ma, though.

ANd anyway, the baby would only be taking the impact of it's own weight*acceleration, not the force of the moms weight or anything else. The seatbelt would take the force of the mom's weight, while the sling would be the thing impacting the baby. THe sling may or may not be strong enough to handle the force of the impact, it depends on the strength of the fabric and the speed you were going befor impact. I doubt the baby would be ejected from a sling as easily as a snugli, but at the same time, there's probably less head support. Plus the sling fabric would usually be more flimsy and likely to tear or break, although the clips on a Snugli are pretty flimsy as well.
Quote:
 Originally Posted by Ironica No link, but there are crash test videos showing what happens to an adult who is belted into the back seat. They often hit the front seat. It's not too difficult to imagine what would happen to a baby between the adult and the front seat.
Is that w/ a lap belt only or a shoulder belt as well? And is it their body or "just" their head?
*Former mechanical engineer*

Trillian is right that Force does not equal weight times speed.

Force equals mass times acceleration. *Note - lbs is a weight not a mass*
Acceleration/deceleration in an accident equals the speed you're traveling divided by how long it takes you to stop.
Momentum equals mass times speed.

The weight of something is it's mass times the acceleration due to gravity. So weight is actually a force. (That's why people are lighter on the moon. The force due to gravity is different.)

Therefore, no, you cannot multiply force times speed and get force.

If you stop suddenly as in an accident your acceleration/deceleration will be very high. The faster you are going, the higher your negative acceleration.

In that respect, the techs have the right idea that force is proportional to both your weight and your speed. In other words, as a persons weight goes up, or as the speed you're travelling goes up, the force in an accident also goes up.

However, a 100 lb person in a 30 mph crash would not have a force of 3000 lbs.

ETA: After working it out a 100 lb person stopping from 30 mph to 0 in 0.2 seconds would have a force of about 684 lbs. That is a very basic conclusion though as there are many more systems and forces at play in an accident.

Regardless of exactly the force during an accident, I wouldn't be comfortable with any amount of weight hitting my baby in a car accident 1000 lbs or 10.
Quote:
 Originally Posted by wendy1221 Force=mass*acceleration, not mass*speed, and the units are lbs per quare inch or whatever, not lbs.
Actually pounds is a valid unit of force, and can be converted to newtons (the SI unit). Pounds per square inch is a unit of pressure.
mass i sproportional weight on earth, though, so there's no reason to differentiate the 2 in these calculations. You can convert your "force" in lbs to your "mass" in kg, and still call your mass in kg your weight. It's just semantics, really.
Quote:
 Originally Posted by Trillian Actually pounds is a valid unit of force, and can be converted to newtons (the SI unit). Pounds per square inch is a unit of pressure.
RIght. I already edited my post b/c I realized that.
Quote:
 Originally Posted by BeckC *Former mechanical engineer* Trillian is right that Force does not equal weight times speed. Force equals mass times acceleration. *Note - lbs is a weight not a mass* Momentum equals mass times speed. The weight of something is it's mass times the acceleration due to gravity. So weight is actually a force. (That's why people are lighter on the moon. The force due to gravity is different.) Therefore, no, you cannot multiply force times speed and get force. If you stop suddenly as in an accident your acceleration/deceleration will be very high. The faster you are going, the higher your negative acceleration. In that respect, the techs have the right idea that force is proportional to both your weight and your speed. In other words, as a persons weight goes up, or as the speed you're travelling goes up, the force in an accident also goes up. However, a 100 lb person in a 30 mph crash would not have a force of 3000 lbs.
Good explanation.
all of these calculation matter only if you are in a collision. whaat are the percentages of collisions while driving defensively? If my baby is screaming, then she is 100% sustaining emotional harm, whereas she only might sustain physical harm.

use a carseat if you want - I usually do, but there are times when the benefits of holding my baby while in a moving vehicle outweigh the risks.
Quote:
 Originally Posted by vbactivist all of these calculation matter only if you are in a collision. whaat are the percentages of collisions while driving defensively? If my baby is screaming, then she is 100% sustaining emotional harm, whereas she only might sustain physical harm. use a carseat if you want - I usually do, but there are times when the benefits of holding my baby while in a moving vehicle outweigh the risks.
The only benefit of holding your baby is that they stop screaming. The RISK is your baby going through the windshield.

Read my above post about my DH's cousin. My aunt didn't think it was a risk either, and she lost her baby to a drunk driver.
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