this post was submitted on 28 Aug 2024
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[–] SpaceNoodle@lemmy.world 68 points 3 weeks ago* (last edited 3 weeks ago) (2 children)

They're traveling away from their origin at constant velocities, so they're traveling relative to each other at constant velocities as well.

The magnitude of the resulting vector (i.e., speed) can be calculated trivially since their movement is perpendicular on a plane, as the root of sum of squares, which many could recognize as the Pythagorean theorem:

√((5 ft/s)² + (1 ft/s)²) = √26 ft/s ≈ 5.1 ft/s

You can verify this by finding that their average speed apart is the same at all times (for all t > 0):

Vavg = √((t * 5 ft/s)² + (t * 1 ft/s)²) / t = √(t² * ((5 ft/s)² + (1 ft/s)²)) / t = √26 ft/s

[–] key@lemmy.keychat.org 24 points 3 weeks ago* (last edited 3 weeks ago) (1 children)

Don't forget to calculate the location where everything about them began and then include the curvature of Earth considering the latitude of said location into your speed calculation.

[–] SpaceNoodle@lemmy.world 34 points 3 weeks ago (3 children)

No, they're spherical children in a vacuum.

[–] answersplease77@lemmy.world 13 points 3 weeks ago

for approximation we can assume that the boy is a point mass and the girl is a lie

[–] ICastFist@programming.dev 5 points 3 weeks ago

Oh, so we have to calculate the gravitational attraction pulling them back. Fucking hell

[–] Hamartia@lemmy.world 2 points 3 weeks ago

Augustus! Save some room for later.

[–] Randelung@lemmy.world 3 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

https://en.m.wikipedia.org/wiki/Spherical_geometry

I couldn't find 'potatoy geometry' for a better approximation of earth.

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

You'll note that I already assumed that they were on a plane, not the surface of a sphere.

[–] Randelung@lemmy.world -1 points 2 weeks ago (1 children)

I'm also noting the stick up your ass. 🙄

If the potato remark and subreddit don't tip you off that I was being flippant, I don't know what will.

[–] SpaceNoodle@lemmy.world 2 points 2 weeks ago

No, the stick would be a one-dimensional line.