jumpinfarmer 0 #1 February 16, 2004 Two friends of mine don't believe that two falling human bodies don't always fall at the same rate. They don't believe me that jumpers fall at different rates. Help! Quote Share this post Link to post Share on other sites
Bodyflight.Net 0 #2 February 16, 2004 maybe you could relate it to weight, in the extremes a brick will fall faster than a feather.. heavier person/more gear logically would fall faster, assuming no effort.. right? Quote Share this post Link to post Share on other sites
FallRate 0 #3 February 16, 2004 Do these friends ride the short bus? FallRate Quote Share this post Link to post Share on other sites
frankiebrina 0 #4 February 16, 2004 tell them to study physics. Quote Share this post Link to post Share on other sites
skydyvr 0 #5 February 16, 2004 You win. . . =(_8^(1) Quote Share this post Link to post Share on other sites
SkydiverRick 0 #6 February 16, 2004 QuoteTwo friends of mine don't believe that two falling human bodies don't always fall at the same rate. They don't believe me that jumpers fall at different rates. Help! In a vacuum, they'd be correct. never pull low......unless you are Quote Share this post Link to post Share on other sites
peacefuljeffrey 0 #7 February 16, 2004 QuoteTwo friends of mine don't believe that two falling human bodies don't always fall at the same rate. They don't believe me that jumpers fall at different rates. Help! Maybe they are confused by the idea of two objects of different mass having the same acceleration due to gravity in an airless void. Add an atmosphere and things change because of drag. If you dropped a feather and a brick on the moon, they will fall at the same rate because there is no drag on either. The moon's pull (actually a relative pull between either pair of objects, moon-and-brick or moon-and-feather) is stronger between the moon and the brick than it is between the moon and the feather -- BUT -- The brick has more mass than the feather, so therefore more INERTIA. It takes longer to get going, like a big fat guy in a race against a small skinny guy. May end up reaching the same speed, but takes more to get it happening. The brick, being pulled harder because of the interaction between masses, thus accelerates slower, proportionally, than the feather does. The feather is quicker to take off because of its low inertia, but then slower because of its lesser mass. So a massive object (brick) gets more pull but has more lard-ass to get moving; the less massive object (feather) can get up and moving quicker because it has less mass but it doesn't have as strong an attraction to the moon. The two cancel out, and fall together. At least, that's how a friend recently explained it to me, refreshing my memory of the physics class I struggled through in high school. Hope it helped you. --Jeffrey "With tha thoughts of a militant mind... Hard line, hard line after hard line!" Quote Share this post Link to post Share on other sites
peacefuljeffrey 0 #8 February 16, 2004 QuoteQuoteTwo friends of mine don't believe that two falling human bodies don't always fall at the same rate. They don't believe me that jumpers fall at different rates. Help! In a vacuum, they'd be correct. In a vacuum, they'd be dead. --Jeffrey "With tha thoughts of a militant mind... Hard line, hard line after hard line!" Quote Share this post Link to post Share on other sites
Lainey 0 #9 February 16, 2004 i know very little about physics... i have a vague idea that there is a speed of acceleration whereby once an object reaches that speed it cannot fall any faster than that no matter what the weight. Now it seems like what you are saying is correct, however this seems to note otherwise... http://web.jjay.cuny.edu/~acarpi/NSC/1-scimethod.htm ?? And you shed not a single tear for the things that you didn't need 'Cause you knew you were finally free - Death Cab For Cutie Quote Share this post Link to post Share on other sites
Lainey 0 #10 February 16, 2004 sorry i don't know how to make that a link. And you shed not a single tear for the things that you didn't need 'Cause you knew you were finally free - Death Cab For Cutie Quote Share this post Link to post Share on other sites
Lainey 0 #11 February 16, 2004 so i guess it's more to do with resistance than weight? or am i missing the point? And you shed not a single tear for the things that you didn't need 'Cause you knew you were finally free - Death Cab For Cutie Quote Share this post Link to post Share on other sites
freeflir29 0 #12 February 16, 2004 Quoteo i guess it's more to do with resistance than weight? or am i missing the point? You're all over it! All objects accelerate at 32Ft per sec per sec but not all have the same terminal in an atmosphere due to wind resistance. I hate that part cause I am 185-190Lbs with relatively short arms and legs. Makes me fall fast..... Quote Share this post Link to post Share on other sites
cocheese 0 #13 February 16, 2004 Show them the last segment of the "Crosswind" video by Patrick Passe where Olav is flying in and out of the big round formation. I know of a skydiver/teacher who had to show this in class because some other teacher told the kids the same thing your friend did. So now all the kids can't wait skydive. Wups. Btw any skydive video will show a variation of fall rates between two jumpers. Especially any of the ones i've been in. Quote Share this post Link to post Share on other sites
bch7773 0 #14 February 16, 2004 oooo ooo I know. tell em that some skydivers have bigger dicks than others, causing a more pointed falling shape, and so they fall faster. then you tell em that you are the fastest faller at your dz. MB 3528, RB 1182 Quote Share this post Link to post Share on other sites
sunshine 2 #15 February 16, 2004 So they don't beleive you...is it that big of a deal? Whuffos are just silly that way. ___________________________________________ meow I get a Mike hug! I get a Mike hug! Quote Share this post Link to post Share on other sites
peacefuljeffrey 0 #16 February 16, 2004 What Lainey is thinking of is "terminal velocity" but it merely applies in an atmosphere, not in a vacuum. That terminal velocity is a function of both the mass of the body and the resistance it gives to the air (its drag). Imagine if what you were saying is true: two people under identical canopies should descend at the same vertical speed too, even despite being different masses -- if greater mass did not translate into greater terminal velocity. Now, this would be different on the moon: a person with an inflated (or "spread out") canopy would fall no slower than a person whose main is in the container. If you believe the myth about objects of different masses falling just as fast as each other -- particularly if they are of the same volume (i.e. different densities) then try to imagine if a kickball and an equal sized bowling ball would both reach the same terminal velocity in freefall. Certainly they would not. The kickball's mass gives it a certain strength of pull toward the center of the earth, and once it speeds up enough so that the drag equals that pull, it stops accelerating. "Terminal velocity." The bowling ball will reach a much higher velocity before drag overcomes its pull toward the earth. This kind of physics is also why your car levels out at a certain speed each time you press the gas just a bit more. Extra gas means more force in the direction of the wind: the car speed up until the additional drag from the wind equals the extra gas you gave the car. --Jeffrey "With tha thoughts of a militant mind... Hard line, hard line after hard line!" Quote Share this post Link to post Share on other sites
sdgregory 0 #17 February 16, 2004 QuoteQuoteQuoteTwo friends of mine don't believe that two falling human bodies don't always fall at the same rate. They don't believe me that jumpers fall at different rates. Help! In a vacuum, they'd be correct. In a vacuum, they'd be dead. Exactly, and dead people are NEVER wrong - Quote Share this post Link to post Share on other sites
blueskyserenity 0 #18 February 16, 2004 Quoteoooo ooo I know. tell em that some skydivers have bigger dicks than others, causing a more pointed falling shape, and so they fall faster. then you tell em that you are the fastest faller at your dz. This seems like a very scientific explanation describing differences in fall rate to me. Good work. I like coconuts. You can break them open and they smell like ladies lying in the sun! Quote Share this post Link to post Share on other sites
leroydb 0 #19 February 16, 2004 there are those that speed skydive way over 350 MPHLeroy ..I knew I was an unwanted baby when I saw my bath toys were a toaster and a radio... Quote Share this post Link to post Share on other sites
Luv2Fall 0 #20 February 16, 2004 Yep, very much like a tandem jump. Yours truly, "Tripod" Quote Share this post Link to post Share on other sites
happythoughts 0 #21 February 16, 2004 It has to do with shape, drag, and weight. A jumper with a packed parachute and an open parachute weigh the same. Guess which one falls the slowest? Quote Share this post Link to post Share on other sites
RyanLikesToFall 0 #22 February 16, 2004 I was always taught that it had to do with surface area. If two skydivers were shaped exactly the same, but one weighed 100 more pounds than the other, wouldn't they fall at the same speed? I thought that's what was proven at the leaning tower? He dropped two balls, same shape, one heavier than the other, and they hit the ground at the same time. Quote Share this post Link to post Share on other sites
turtlespeed 226 #23 February 16, 2004 QuoteQuoteTwo friends of mine don't believe that two falling human bodies don't always fall at the same rate. They don't believe me that jumpers fall at different rates. Help! In a vacuum, they'd be correct. In a vacuum the blood would boil and decompression would happen - so, no, but pieces would be falling at the same rate - unless you factor in the acceleration of the pieces as they explosively decompress out of the body.I know, I kant spel gud!I'm not usually into the whole 3-way thing, but you got me a little excited with that. - Skymama BTR #1 / OTB^5 Official #2 / Hellfish #408 / VSCR #108/Tortuga/Orfun Quote Share this post Link to post Share on other sites
samhussey 0 #24 February 16, 2004 Did they have enough time to reach terminal velocity though? Quote Share this post Link to post Share on other sites
happythoughts 0 #25 February 16, 2004 QuoteI was always taught that it had to do with surface area. If two skydivers were shaped exactly the same, but one weighed 100 more pounds than the other, wouldn't they fall at the same speed? The speed of skyballs is adjusted by adding weight inside. The shape does not change, but the speed does. Also, if you take a skydiver and change his drag by changing the suit, then you change the speed. Go from polycotton to nylon, the drag changes and the speed changes. Quote Share this post Link to post Share on other sites
