/sci/ - Science & Math » Thread #7618859

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Anonymous Tue 27 Oct 2015 09:02:16 No.7618859 View Reply Report Delete

Quoted By: >>7618881 >>7619013 >>7620799

https://www.youtube.com/watch?v=gzYJaQ0h4Dg
>norwegian guy out parachuting
>rock flies by like a child threw it
>DUDE METEORS LMAO

How is the rock going so slow? Could it have entered in a very flat entry point and then sorta just dropped down, instead of a hard entry?

Anonymous

Anonymous Tue 27 Oct 2015 09:22:10 No.7618881 Report Delete

Quoted By: >>7621011

>>7618859
Assume a rock is roghly spherical.

Look at the equation for a sphere: as the radius increases the volume increases faster than the cross section of the rock.

Air resistance acts on the cross section of an object whereas mass and therefor total kinetic energy depends on volume.

tl;dr aerobraking

Anonymous

Anonymous Tue 27 Oct 2015 09:26:33 No.7618887 Report Delete

Quoted By: >>7618932

>How is the rock going so slow?

They showed it in slow motion

Anonymous

Anonymous Tue 27 Oct 2015 10:13:22 No.7618932 Report Delete

Quoted By:

>>7618887
Ooh.

Anonymous

Anonymous Tue 27 Oct 2015 11:28:00 No.7619013 Report Delete

Quoted By: >>7620735

>>7618859
Maybe a rock fell from the aircraft after he jumped.

Anonymous

Anonymous Wed 28 Oct 2015 02:41:51 No.7620735 Report Delete

Quoted By: >>7620769 >>7620816

>>7619013
it would fall at about the same speed as him not faster like in the video

Anonymous

Anonymous Wed 28 Oct 2015 03:01:13 No.7620769 Report Delete

Quoted By: >>7621011

>>7620735
No it wouldnt, smaller things fall faster than larger things.

Anonymous

Anonymous Wed 28 Oct 2015 03:18:00 No.7620799 Report Delete

Quoted By:

>>7618859
the rock decelerated to it's terminal velocity.

Anonymous

Anonymous Wed 28 Oct 2015 03:36:22 No.7620816 Report Delete

Quoted By:

>>7620735

He had just opened his parachute dumdum.

Anonymous

View Same Google ImgOps iqdb SauceNAO 1388161.jpg, 278KiB, 800x600

Anonymous Wed 28 Oct 2015 03:56:50 No.7620834 Report Delete

Quoted By:

>watched that video
>now walking around like a paranoid waiting for a rock to fall from the sky
Gee, thanks.

Anonymous

Anonymous Wed 28 Oct 2015 07:40:20 No.7621000 Report Delete

Quoted By:

Parachutes get folded how?

>you lay them on the ground and fold them in a certain--

If a rock had gotten folded up in his parachute, accidentally or intentionally, would the chute still open?

>yeah, I guess it--

Is it more likely for a rock to get folded up in a parahute, either accidentally or intentionally, or for a skydiver to almost be struck by a falling meteor?

>It's probably way more likely for a rock to get folded up in--

K.

Anonymous

Anonymous Wed 28 Oct 2015 07:48:17 No.7621011 Report Delete

Quoted By:

>>7620769
refer to
>>7618881
(aka "square cube law")

mass/cross section area is what counts (and shape specific aerodynamics, but let's not get into that)
smaller generally means smaller ratio, so falls slower
that's also the reason why finer dust gets swept up by wind easier, etc

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