just a newbie question

[helvetefrosk 0]

hello all!
i have a newbie question. when a sky diver falls from the plane and during the period of the freefall does the weight of the sky-diver has any effect on the rate of the fall? in other words, does a heavy weight sky-diver falls at a faster rate than a lighter one ?

[Gravitymaster 0]

yes

[helvetefrosk 0]

oh really? hmmm...this seems weird because i just had my physics lessons and it says all objects/matter falls to the ground at the same rate in regardless of it's weight. science can be so confusing anyway, thanks for the answer.

[masher 1]

The key phrase you're missing is "Neglecting air resistance"

If you factor air resistance in, then you get varying fall rates.

I've done fluid physics at uni, and the calculations are _much_ easier when you neglect air resistance, but the answers don't bear much relation to real world things.

--
Arching is overrated - Marlies

[aero04 0]

This is true, but ONLY in a vacuum. We have air resistance in freefall, and that has an effect on velocity. The heavier the person, the faster they will fall. Think about forces from your physics class. To reach terminal velocity, the downward force (gravity) must equal the "upward" force (air resistance). Assuming your still accerating toward terminal velocity, for a 200 pound jumper, the downward force will be larger (F=ma) than a 150 pound jumper, thus meaning the air resistance must be higer for the forces to sum to 0, and in order to "obtain" the higher air resistance, your velocity must be higher.

Hope this helps.

Edit: I can't think straight right now. Thanx for the correction Casch.

[Casch 0]

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The more surface area one has, i.e. a larger person, the faster they will fall.

Are ya tryin' to confuse the man! I think ya got it backwards, the more surface area you have, the slower you will fall.

That is to say, if a 5'9" 250lb guy (i.e. ME) and a 6'6" 250lb guy both hold the same body position, the taller guy will generally fall slower or "Float". Other ways to change your fallrate are; cup air with your body, sorta like you're hugging a beach ball. This presents more surface area to the wind, and creates more drag and you will slow down, if you arch really hard, or go into a sit/head down/standing freefall, you will fall much faster

[aero04 0]

Whoops, yea, guess I'm a bit more tired than I thought. Didn't think that one through. I should have just said a heavier person will fall faster. Gotta fix that post...

[ccowden 0]

Fact of the matter is- heavier doesn't always mean faster, ie: 200lb guy who is 6'5" vs. 190lb guy who is 5'4"- and there are tons of things that effect the fallrate besides weight like surface area, jumpsuit, body position, etc....
But it is all due to air resistance. Take that away and yes, everything falls at the same speed. In a vacuum.
Science is not confusing- humans are!

[helvetefrosk 0]

hey everyone

[kizza 0]

Check out this thread

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=463743;sb=post_latest_reply;so=ASC;forum_view=forum_view_collapsed;guest=1092422

[feelopen 0]

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=463743;sb=post_latest_reply;so=ASC;forum_view=forum_view_collapsed;guest=1092422

[Fireflyer 0]

feathers and bricks drop at the same rate - in a vacuum.

dont neglect the air resistance!

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oh really? hmmm...this seems weird because i just had my physics lessons and it says all objects/matter falls to the ground at the same rate in regardless of it's weight. science can be so confusing anyway, thanks for the answer.