A baby leaves Seattle going east at 18km/s another baby leaves New York going west at 34km/s, how long before each baby clears the heliopause. Please show your workings out.

Mph: the child crashes on Mars

That is speed

Child services:

How would you frame a sentence here for velocity then?

16.4 MPH in that direction?

I find the absurdity of the joke would be better if the mother asked, "In which direction?"

She had it coming. If you use months after 1 year, prepare to get slammed.

Pff, doesn't even use SI units.

Chris has not seen a 32 month old toddler in his life.

Month's what?

She said she likes math not grammar!

To explain this joke: velocity is a vector quantity, so it has a magnitude (speed) and a direction, which mom failed to indicate, shame on her.

Velocity is speed and direction. So "16.4 mph north" is sufficient.

Months*

Oh man, that caught me so offguard it made me do one of those sudden "neighbor jumpscare" type cackling laughs I'm sure was heard next door lol

Am I the only one who thought Kris was a lady uptil now? Maybe I was just projecting because I liked the cutesier style of these ones lol

There's a Ryan Gosling gif for everything lmao

The normal age to stop using months is 2 years.

That's because there's a massive difference between a 12, 18, and 24 months old. It makes sense to have and use different references to separate them.

It is not. It's not in metric.

Those ages are a year, a year and a half, and two years.

I surely prefer him than DiCaprio

It makes more sense when you're comparing month to month development.

If you have a perfectly normal child then it doesn't matter to measure anything and you can call it whatever.

However if you're in a maternity group and all the other children started pointing at things at 13 months and yours doesn't, then it might help to remember that yours was born prematurely and you can expect that behavior at 14 months.

Now, you can convert numbers as much as you please, but this doesn't make sense as 1.08 and 1.16 years. You can say one year and one month and one year and two months, but it does makes sense for everyone in the conversation if you use the conventional method of communication which is 13 and 14 months. Don't even get me started on Tiger leaps. Those come on schedule by the week.

It's convention. If you go to a car mechanic to get new tires, you also don't ask for "big wheels" if you want a 226/40R19.

NOT LIKE THAT

I know for a fact this isn’t right but it’s probably close enough to work. About 30-32 years for infant 1, and infant 2 doesn’t work with this approximation at all, but I’m so long out of physics classes that I don’t know how to calculate it properly. But it was fun to try!

My work:

The voyager crafts launched in 1977 and cleared the heliopause in 2012 and 2018. Your proposed infant 1 is going 1km/s faster than voyager 1 (17km/s) which cleared in 2012, and 3km/s faster than 2 (15km/s) which cleared in 2018.

Voyager 1 took 35 years, voyager 2 took 41 years, meaning that 2km/s different amounts to ~6 years, or 3 years per 1km/s

Subtract that 3 years from the time it took for voyager 1 because your infant is moving 1km/s faster, and you get about 32 yrs. Add in some wiggle room because it’s not exactly linear, and 30-32yrs.

This approximation totally broke down with infant 2 due to the scale of difference in speed, and had it getting there before it launched. If you take the same 3 yrs/1km/s, and multiply it by 16, which is the difference between the infants’ speeds, you get 48 years, which would put it there before it launched based on voyager 1 taking 35 yrs. 🤷🏻

As a proud owner of a 23 month old toddler, I can confirm that even my specimen is larger than that, and I could not dream to achieve that kind of velocity.

So "16.4 mph north" is sufficient.

No, it's not. "North" is a two dimensional direction on the surface of the earth. But we live, and can throw babies, in three dimension. Therefore you need to specify the inclination as well. "56 furlongs per minute, north, 0.3 radians" would suffice.

No metric units? No regret.

The surface of the Earth is 3d object, thus moving North is a 3d vector which modifies the baby's velocity relative to the Earth's center of gravity as it curves the movement of the baby flying through the air.

That's absolutely right, but ignores context. People often use months even when the exact age isn't relevant to the other person.
If I (as someone who doesn't have kids and don't know anything about e.g. what behavior is appropriate at what month at all) ask a friend "how old is she now?", I'd be fine with a "about a year and a half" or "she's getting 1 year old next month" or whatever. I don't need an exact month cause 1 month difference doesn't matter to me in a casual smalltalk/conversation setting. I wouldn't know "oh, that's the month she might start pointing at things" anyways.

Of course I'm aware that parents are probably just used to it, so I'm not mad when someone says it in months. But I'd prefer it in years if I had the choice.

To reuse your analogy, I would say 226/40R19 to my mechanic, but to my mother I'd say I'm buying "big wheels". Cause she doesn't know what exactly 226/40R19 is/means, so "big wheels" conveys the information better to her.

The problem is that there are an infinite number of directions that are going north. Going north parallell to the ground is not the same direction as an upwards or downwards path. You can have any inclination between (-pi/2, pi/2) and still be going north. If you don't specify the inclination, it is likely to be assumed to be zero, i.e. the baby is moving parallell to the earths normal plane, but it's it is uncertain. That's why you need two vectors in 3d space.

I suppose I see "North" as more of a function rather than a variable. When you specify North you're specifying a relative direction. Because the vector one takes to go North from the US is not the same vector one takes from Russia. The issue is we're mapping a direction to a point on a sphere So yes North isn't an absolute vector, but it is a shortcut to calculating the vector to the location you want to go.
If I was writing this function, I could easily add in a check to determine if we're heading towards the equator before we hit North or not based on the vector direction. And just keep it stuck to the sphere's normal. The initial inclination would be used for calculating the initial vector.
I think our wires are getting crossed cause I'm used to 3d programming and velocity is usually spd * (x, y, z) and the inclinations and such you're speaking of are baked into the (x, y, z) vector that is calculated to determine the "direction" part of the "direction + magnitude" definition of a vector. (I'm enjoying this by the way)