this post was submitted on 28 Aug 2024
470 points (98.4% liked)

196

16449 readers
2330 users here now

Be sure to follow the rule before you head out.

Rule: You must post before you leave.

^other^ ^rules^

founded 1 year ago
MODERATORS
 
you are viewing a single comment's thread
view the rest of the comments
[–] [email protected] 68 points 2 months ago* (last edited 2 months 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

[–] [email protected] 24 points 2 months ago* (last edited 2 months 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.

[–] [email protected] 34 points 2 months ago (3 children)

No, they're spherical children in a vacuum.

[–] [email protected] 13 points 2 months ago

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

[–] [email protected] 5 points 2 months ago

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

[–] [email protected] 2 points 2 months ago

Augustus! Save some room for later.

[–] [email protected] 3 points 2 months ago* (last edited 2 months ago) (1 children)

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

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

[–] [email protected] 1 points 2 months ago (1 children)

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

[–] [email protected] -1 points 2 months 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.

[–] [email protected] 2 points 2 months ago

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