Yes, if you want to be pedantic, velocity a vector with direction, so I guess you’d have to frame the question relative to either the boyfriend or girlfriend, but I don’t think the difference between speed and velocity is part of the question.

[–] SpaceNoodle@lemmy.world 2 points 2 months ago (2 children)

Speed is just the magnitude of velocity.

My point is that OC was completely missing the mark by not properly accounting for time.

[–] dabaldeagul@feddit.nl 2 points 2 months ago (1 children)

Hi, I made this in 5 mins because I was bored, but it's late and I'm tired, so could you please explain what I would have to fix in my comment?

[–] ji17br@lemmy.ml 3 points 2 months ago (1 children)

You want to figure out distance per second. One way to do this is calculate distance apart at t=0,1,2…

The difference between each point would be the average speed over that second.

Using sqrt(b^2+g^2):

t0 = 0 t1 = 1.554m
s1 = (1.554m-0m)/1s = 1.554m/s t2 = 3.108m
s2=(3.108m-1.554m)= 1.554m/s

As you continue this you will see they travel at a constant speed apart from each other. The reason this is working is because you need to divide distance by time. Dividing by 1 second won’t change the value of the number after you subtract. If you notice you can do (t2-t0)/2s and also get the same answer.

[–] dabaldeagul@feddit.nl 1 points 2 months ago

Ahhh okay, thanks

[–] ji17br@lemmy.ml 1 points 2 months ago (1 children)

My mistake, I didn’t check his math. I thought he was saying if you take distance apart at t(n) and subtract distance apart at t(n-1) you will get distance/sec.

[–] SpaceNoodle@lemmy.world 1 points 2 months ago (1 children)

Only if you divide by time. Including units is an essential sanity check.

Also, the rest of the math needs to be correct.

[–] ji17br@lemmy.ml 1 points 2 months ago (1 children)

Well that’s my point. The answer is correct in this specific case, because it’s already “built-in” so to speak.

[–] SpaceNoodle@lemmy.world 1 points 2 months ago (1 children)

No, their answer is wrong.

[–] ji17br@lemmy.ml 1 points 2 months ago

I’m talking about my previous response. I already said their answer is wrong.