corpkid 0 #1 February 10, 2004 I remember from school that all objects fall at the same rate - sans friction. Why is it that tandems fall faster than solo jumpers (and thus the drouge chute)? I have a debate with my friend on this so any help is appreciated. Also, if you could indicate why people use weight belts, that would be most helpful. Thanks so much! Dominic Quote Share this post Link to post Share on other sites
CanuckInUSA 0 #2 February 10, 2004 What they taught you in school was that the objects would accelerate at the same rate, not that they would fall at the same rate. Try not to worry about the things you have no control over Quote Share this post Link to post Share on other sites
crutch 0 #3 February 10, 2004 This is pretty easy, speed/terminal velocity is a factor of weight versus drag. A tandem has twice the weight, but not twice the surface area being presented into the wind.blue skies, art Quote Share this post Link to post Share on other sites
jakee 1,556 #4 February 10, 2004 you said it yourself, things fall at the same rate in the absence of friction. Skydivers have much friction, enough friction (well, drag) at terminal velocity to completely support your weight. force up = force down.Do you want to have an ideagasm? Quote Share this post Link to post Share on other sites
Lee03 0 #5 February 10, 2004 All the answers below make sense to me, but then, I thought physics started with an "F" Good question-------- To put your life in danger from time to time ... breeds a saneness in dealing with day-to-day trivialities. --Nevil Shute, Slide Rule Quote Share this post Link to post Share on other sites
Nutz 0 #6 February 10, 2004 All things fall at the same rate in a vacuum. Sinse we don't live in a vacuum things of different weight and area fall at different rates. Tamdem = twice the weight but basically the same area as a single skydiver thus the need for a drogue to slow them down. Make sense? "Don't! Get! Eliminated!" Quote Share this post Link to post Share on other sites
Vertifly 0 #7 February 10, 2004 I asked the same question (well, in a way) to my tandem master at about 3 jumps. Here is how the conversation went: Me: "Hey Mike, I don't quite understand the concept of objects and their speeds at terminal velocity." Mike: "Well, what about it?" Me: "I thought that DaVince did the experiment where two cannon balls of different sizes were dropped from the leaning tower of Piza." Mike: "Yeah, And???" Me: "They both hit the ground at the same time." Mike: "And???" Me: "Well, if they both hit the ground at the same time, then that would mean that all objects fall at the same terminal velocity. This is what he proved with the experiment" Mike: "Well, how tall is the leaning tower of piza." Me: "I don't know! About 25 or 30 stories I would guess." Mike: "That isn't enough time for them to reach terminal velocity." Me: "mmmm...ok I guess" So what have we learned from this? This is what: (1) Never assume that your tandem master understands the properties of physics. (2) Don't bother your tandem master with stupid questions. And (3) go find all of the answers that you want from the public library. It's more time consuming but tends to send you off with the correct info. The truth is that those canon balls would fall at the same speed during terminal velocity. Why? Because they are the same shape and density. "Weight" itself has little to do with it; the weight amount is a result of material density. A solid steel ball will fall faster than a baseball no matter what size they are made into. A steel ball is always more dense then a leather and rubber ball. But, then take the baseball sized steel ball and melt it into the shape of an umbrella - with about a 5 foot diamater. The real/regular baseball speed will probably either just about match or be faster than the umbrella made of steel. Hope that analogy helps. Quote Share this post Link to post Share on other sites turnlow 0 #8 February 10, 2004 Check this link for the physics: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=693120;#693120 __________________________________________________It matters not how strait the gate, How charged with punishments the scroll, I am the master of my fate: I am the captain of my soul. Quote Share this post Link to post Share on other sites kallend 2,099 #9 February 10, 2004 Quote A solid steel ball will fall faster than a baseball no matter what size they are made into. What if the steel ball is 0.01mm in diameter? Will it fall faster than a baseball?... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites kallend 2,099 #10 February 10, 2004 QuoteCheck this link for the physics: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=693120;#693120 __________________________________________________ All that thread does is illustrate the abysmal level of physics education in the population at large.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites pilotdave 0 #11 February 10, 2004 I gotta disagree with ya. Size does matter. Scaling effects play major roles in aerodynamics. Look up Reynolds number. Dave Quote Share this post Link to post Share on other sites Harksaw 0 #12 February 10, 2004 From the massive amounts of time I spend thinking about usually stupid stuff.... Couldn't a tandem potentially sit-fly next to a normal sitflyer (before the drogue is released?) Yes, i realize its a bad idea. I'm talking theoretically.__________________________________________________ I started skydiving for the money and the chicks. Oh, wait. Quote Share this post Link to post Share on other sites sdgregory 0 #13 February 10, 2004 You mean couldn't the solo Sit Fly next to the tandem? Remember the tandem is falling faster before the drouge. Quote Share this post Link to post Share on other sites Vertifly 0 #14 February 10, 2004 If size does matter then: | <- here-to-here -> | ...is actually six inches. LOL At least, that is what she told you correct. Just kidding. You are correct. Weight does play a roll. But for the lamen, density will provide you with a closer answer. Density considers the weight and size of an object. It is actually two of the following variables which are considered in the terminal velocity equation. Wieght, Velocity, Density, Drag, Frontal Area, and Drag Coefficients are the different variables. Think about it for a minute. To calculate an objects density, we must measure its weight and size. I mean, that is what density is. Weight divided by Mass. Terminal Velocity is reached when Drag is equal to Weight. Plain and simple. But with more drag (or less density) a slower terminal velocity is accomplished. With more weight in the same object (or more density) a faster terminal velocity will be accomplished. The terminal velocity equation tells us that an object with a large cross-sectional area or a high drag coefficient will fall slower than an object with a small. (A large flat plate will fall slower than an a small ball with the same weight.)This is basically the same definition as my umbrella senario. And if we had two objects with the same area and drag coefficient (two identically sized spheres), the lighter object would fall slower. So, in a way we are both correct. Quote Share this post Link to post Share on other sites Chrisky 0 #15 February 10, 2004 Well. a tandem in a sitfly (funny thought) would actually create about twice the drag surface compared to a solo sit (that is considering that the student is not sitting on the instructors lap, but in front of it between his legs). This is because the instructor would not be in the wind shadow of the student. Thus it should be falling at about the same rate (reach the same terminal velocity) as a solo sit. If they would be able to maintain that position until breakoff, the drogue would have to be deployed once they turn to their belly, effectively reducing their drag surface as the instructor "hides" his surface behind the student...The mind is like a parachute - it only works once it's open. From the edge you just see more. ... Not every Swooper hooks & not every Hooker swoops ... Quote Share this post Link to post Share on other sites mjosparky 4 #16 February 10, 2004 Does "surface area to mass" bring anything to mind? If "1" has 3 sq. ft of surface area and weighs 100 lbs "1" will fall faster than "2" if "2" has 3 sq. ft. of surface area and weighs 50 lbs. Hence you have drogues for tandems and weight belts for skinny skydivers. Does that sound right John? SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites osuskydiver 0 #17 February 10, 2004 Same reason you go faster on a rodeo jump or freefly. But in physics, things fall at the same rate only in a vacuum. Don;t have to worry about drag in there. By the time you read this you have already read it. Quote Share this post Link to post Share on other sites corpkid 0 #18 February 10, 2004 This is what I thought! You guys/gals are sooo smart! I wouldn't bother my over-worked tandem master with such questions - everytime I turned around the guy was landing with another person attached - must get tiring! Anyhow - So what the #$@ do you use a weight belt for? (newbie question, I'm sure). I understand to fall faster (or hit terminal velocity faster), but WHY would you want to fall faster? I personally would want to prolong freefall as long as possible. Which brings me to another question - because freefall is so much fun, and goes by so quick, why don't solo jumpers use a drouge to slow them down so they get more time? My only thought would be the introduction of extra "components" which could complicate things in an emergency... SO MUCH TO LEARN! Thanks! Quote Share this post Link to post Share on other sites mr2mk1g 10 #19 February 10, 2004 People wear weight belts to match freefall speeds with their friends. If you are light and your mate is heavy your mate will fall faster than you. If you want to fall with them you have to make yourself heavier. No drogue cos you can do less (only solo flat) and they introduce a lot of dangers. Imagine getting tangled up in somone elses drogue... or two people flying close and having their drogues tangle.... Quote Share this post Link to post Share on other sites jerry81 10 #20 February 10, 2004 Quote Anyhow - So what the #$@ do you use a weight belt for? (newbie question, I'm sure). I understand to fall faster (or hit terminal velocity faster), but WHY would you want to fall faster? I personally would want to prolong freefall as long as possible. Weight belts are usually worn in formation skydiving, by lighter people who need to match their fallrate with others on their team. And then there was this belly-flyer who filmed a freefly team wearing weights, but I don't want to get started on that one. One more thing weights can be used for is for swooping, where the performance of the parachute is partially determined by wingloading (weight to canopy surface ratio). Quote Which brings me to another question - because freefall is so much fun, and goes by so quick, why don't solo jumpers use a drouge to slow them down so they get more time? My only thought would be the introduction of extra "components" which could complicate things in an emergency... That, and a drogue would also limit your range of movement in the air. Loops, barrel rolls, tracking, just to name a few of the things that would be quite difficult with a drogue trailing behind you. There are these things called wingsuits, however, which still limit some movement a bit, but are on the other hand the closest we can currently get to actual body flight and seriously fun. (Check the wingsuit forum and the Birdman site if you haven't already.) Quote SO MUCH TO LEARN! One of the greatest things about this sport! Quote Share this post Link to post Share on other sites The111 1 #21 February 10, 2004 I think you missed kallend's and dave's point. For simplicity, air is often assumed to be a continuum, and in most cases this is a somewhat adequate assumption. But it's still an assumption; air is NOT a continuum, and scaling/size of the object does matter, since the size of air molecules stays constant.www.WingsuitPhotos.com Quote Share this post Link to post Share on other sites jumpingjoe 0 #22 February 10, 2004 For those of you who want to read this: http://hypertextbook.com/facts/JianHuang.shtml Interesting stuff here. Blue Skies Quote Share this post Link to post Share on other sites Join the conversation You can post now and register later. If you have an account, sign in now to post with your account. Note: Your post will require moderator approval before it will be visible. Reply to this topic... × Pasted as rich text. Paste as plain text instead Only 75 emoji are allowed. × Your link has been automatically embedded. Display as a link instead × Your previous content has been restored. Clear editor × You cannot paste images directly. Upload or insert images from URL. Insert image from URL × Desktop Tablet Phone Submit Reply 0 Go To Topic Listing
turnlow 0 #8 February 10, 2004 Check this link for the physics: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=693120;#693120 __________________________________________________It matters not how strait the gate, How charged with punishments the scroll, I am the master of my fate: I am the captain of my soul. Quote Share this post Link to post Share on other sites
kallend 2,099 #9 February 10, 2004 Quote A solid steel ball will fall faster than a baseball no matter what size they are made into. What if the steel ball is 0.01mm in diameter? Will it fall faster than a baseball?... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
kallend 2,099 #10 February 10, 2004 QuoteCheck this link for the physics: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=693120;#693120 __________________________________________________ All that thread does is illustrate the abysmal level of physics education in the population at large.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
pilotdave 0 #11 February 10, 2004 I gotta disagree with ya. Size does matter. Scaling effects play major roles in aerodynamics. Look up Reynolds number. Dave Quote Share this post Link to post Share on other sites
Harksaw 0 #12 February 10, 2004 From the massive amounts of time I spend thinking about usually stupid stuff.... Couldn't a tandem potentially sit-fly next to a normal sitflyer (before the drogue is released?) Yes, i realize its a bad idea. I'm talking theoretically.__________________________________________________ I started skydiving for the money and the chicks. Oh, wait. Quote Share this post Link to post Share on other sites
sdgregory 0 #13 February 10, 2004 You mean couldn't the solo Sit Fly next to the tandem? Remember the tandem is falling faster before the drouge. Quote Share this post Link to post Share on other sites
Vertifly 0 #14 February 10, 2004 If size does matter then: | <- here-to-here -> | ...is actually six inches. LOL At least, that is what she told you correct. Just kidding. You are correct. Weight does play a roll. But for the lamen, density will provide you with a closer answer. Density considers the weight and size of an object. It is actually two of the following variables which are considered in the terminal velocity equation. Wieght, Velocity, Density, Drag, Frontal Area, and Drag Coefficients are the different variables. Think about it for a minute. To calculate an objects density, we must measure its weight and size. I mean, that is what density is. Weight divided by Mass. Terminal Velocity is reached when Drag is equal to Weight. Plain and simple. But with more drag (or less density) a slower terminal velocity is accomplished. With more weight in the same object (or more density) a faster terminal velocity will be accomplished. The terminal velocity equation tells us that an object with a large cross-sectional area or a high drag coefficient will fall slower than an object with a small. (A large flat plate will fall slower than an a small ball with the same weight.)This is basically the same definition as my umbrella senario. And if we had two objects with the same area and drag coefficient (two identically sized spheres), the lighter object would fall slower. So, in a way we are both correct. Quote Share this post Link to post Share on other sites Chrisky 0 #15 February 10, 2004 Well. a tandem in a sitfly (funny thought) would actually create about twice the drag surface compared to a solo sit (that is considering that the student is not sitting on the instructors lap, but in front of it between his legs). This is because the instructor would not be in the wind shadow of the student. Thus it should be falling at about the same rate (reach the same terminal velocity) as a solo sit. If they would be able to maintain that position until breakoff, the drogue would have to be deployed once they turn to their belly, effectively reducing their drag surface as the instructor "hides" his surface behind the student...The mind is like a parachute - it only works once it's open. From the edge you just see more. ... Not every Swooper hooks & not every Hooker swoops ... Quote Share this post Link to post Share on other sites mjosparky 4 #16 February 10, 2004 Does "surface area to mass" bring anything to mind? If "1" has 3 sq. ft of surface area and weighs 100 lbs "1" will fall faster than "2" if "2" has 3 sq. ft. of surface area and weighs 50 lbs. Hence you have drogues for tandems and weight belts for skinny skydivers. Does that sound right John? SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites osuskydiver 0 #17 February 10, 2004 Same reason you go faster on a rodeo jump or freefly. But in physics, things fall at the same rate only in a vacuum. Don;t have to worry about drag in there. By the time you read this you have already read it. Quote Share this post Link to post Share on other sites corpkid 0 #18 February 10, 2004 This is what I thought! You guys/gals are sooo smart! I wouldn't bother my over-worked tandem master with such questions - everytime I turned around the guy was landing with another person attached - must get tiring! Anyhow - So what the #$@ do you use a weight belt for? (newbie question, I'm sure). I understand to fall faster (or hit terminal velocity faster), but WHY would you want to fall faster? I personally would want to prolong freefall as long as possible. Which brings me to another question - because freefall is so much fun, and goes by so quick, why don't solo jumpers use a drouge to slow them down so they get more time? My only thought would be the introduction of extra "components" which could complicate things in an emergency... SO MUCH TO LEARN! Thanks! Quote Share this post Link to post Share on other sites mr2mk1g 10 #19 February 10, 2004 People wear weight belts to match freefall speeds with their friends. If you are light and your mate is heavy your mate will fall faster than you. If you want to fall with them you have to make yourself heavier. No drogue cos you can do less (only solo flat) and they introduce a lot of dangers. Imagine getting tangled up in somone elses drogue... or two people flying close and having their drogues tangle.... Quote Share this post Link to post Share on other sites jerry81 10 #20 February 10, 2004 Quote Anyhow - So what the #$@ do you use a weight belt for? (newbie question, I'm sure). I understand to fall faster (or hit terminal velocity faster), but WHY would you want to fall faster? I personally would want to prolong freefall as long as possible. Weight belts are usually worn in formation skydiving, by lighter people who need to match their fallrate with others on their team. And then there was this belly-flyer who filmed a freefly team wearing weights, but I don't want to get started on that one. One more thing weights can be used for is for swooping, where the performance of the parachute is partially determined by wingloading (weight to canopy surface ratio). Quote Which brings me to another question - because freefall is so much fun, and goes by so quick, why don't solo jumpers use a drouge to slow them down so they get more time? My only thought would be the introduction of extra "components" which could complicate things in an emergency... That, and a drogue would also limit your range of movement in the air. Loops, barrel rolls, tracking, just to name a few of the things that would be quite difficult with a drogue trailing behind you. There are these things called wingsuits, however, which still limit some movement a bit, but are on the other hand the closest we can currently get to actual body flight and seriously fun. (Check the wingsuit forum and the Birdman site if you haven't already.) Quote SO MUCH TO LEARN! One of the greatest things about this sport! Quote Share this post Link to post Share on other sites The111 1 #21 February 10, 2004 I think you missed kallend's and dave's point. For simplicity, air is often assumed to be a continuum, and in most cases this is a somewhat adequate assumption. But it's still an assumption; air is NOT a continuum, and scaling/size of the object does matter, since the size of air molecules stays constant.www.WingsuitPhotos.com Quote Share this post Link to post Share on other sites jumpingjoe 0 #22 February 10, 2004 For those of you who want to read this: http://hypertextbook.com/facts/JianHuang.shtml Interesting stuff here. Blue Skies Quote Share this post Link to post Share on other sites Join the conversation You can post now and register later. If you have an account, sign in now to post with your account. Note: Your post will require moderator approval before it will be visible. Reply to this topic... × Pasted as rich text. Paste as plain text instead Only 75 emoji are allowed. × Your link has been automatically embedded. Display as a link instead × Your previous content has been restored. Clear editor × You cannot paste images directly. Upload or insert images from URL. Insert image from URL × Desktop Tablet Phone Submit Reply 0
Chrisky 0 #15 February 10, 2004 Well. a tandem in a sitfly (funny thought) would actually create about twice the drag surface compared to a solo sit (that is considering that the student is not sitting on the instructors lap, but in front of it between his legs). This is because the instructor would not be in the wind shadow of the student. Thus it should be falling at about the same rate (reach the same terminal velocity) as a solo sit. If they would be able to maintain that position until breakoff, the drogue would have to be deployed once they turn to their belly, effectively reducing their drag surface as the instructor "hides" his surface behind the student...The mind is like a parachute - it only works once it's open. From the edge you just see more. ... Not every Swooper hooks & not every Hooker swoops ... Quote Share this post Link to post Share on other sites
mjosparky 4 #16 February 10, 2004 Does "surface area to mass" bring anything to mind? If "1" has 3 sq. ft of surface area and weighs 100 lbs "1" will fall faster than "2" if "2" has 3 sq. ft. of surface area and weighs 50 lbs. Hence you have drogues for tandems and weight belts for skinny skydivers. Does that sound right John? SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
osuskydiver 0 #17 February 10, 2004 Same reason you go faster on a rodeo jump or freefly. But in physics, things fall at the same rate only in a vacuum. Don;t have to worry about drag in there. By the time you read this you have already read it. Quote Share this post Link to post Share on other sites
corpkid 0 #18 February 10, 2004 This is what I thought! You guys/gals are sooo smart! I wouldn't bother my over-worked tandem master with such questions - everytime I turned around the guy was landing with another person attached - must get tiring! Anyhow - So what the #$@ do you use a weight belt for? (newbie question, I'm sure). I understand to fall faster (or hit terminal velocity faster), but WHY would you want to fall faster? I personally would want to prolong freefall as long as possible. Which brings me to another question - because freefall is so much fun, and goes by so quick, why don't solo jumpers use a drouge to slow them down so they get more time? My only thought would be the introduction of extra "components" which could complicate things in an emergency... SO MUCH TO LEARN! Thanks! Quote Share this post Link to post Share on other sites
mr2mk1g 10 #19 February 10, 2004 People wear weight belts to match freefall speeds with their friends. If you are light and your mate is heavy your mate will fall faster than you. If you want to fall with them you have to make yourself heavier. No drogue cos you can do less (only solo flat) and they introduce a lot of dangers. Imagine getting tangled up in somone elses drogue... or two people flying close and having their drogues tangle.... Quote Share this post Link to post Share on other sites
jerry81 10 #20 February 10, 2004 Quote Anyhow - So what the #$@ do you use a weight belt for? (newbie question, I'm sure). I understand to fall faster (or hit terminal velocity faster), but WHY would you want to fall faster? I personally would want to prolong freefall as long as possible. Weight belts are usually worn in formation skydiving, by lighter people who need to match their fallrate with others on their team. And then there was this belly-flyer who filmed a freefly team wearing weights, but I don't want to get started on that one. One more thing weights can be used for is for swooping, where the performance of the parachute is partially determined by wingloading (weight to canopy surface ratio). Quote Which brings me to another question - because freefall is so much fun, and goes by so quick, why don't solo jumpers use a drouge to slow them down so they get more time? My only thought would be the introduction of extra "components" which could complicate things in an emergency... That, and a drogue would also limit your range of movement in the air. Loops, barrel rolls, tracking, just to name a few of the things that would be quite difficult with a drogue trailing behind you. There are these things called wingsuits, however, which still limit some movement a bit, but are on the other hand the closest we can currently get to actual body flight and seriously fun. (Check the wingsuit forum and the Birdman site if you haven't already.) Quote SO MUCH TO LEARN! One of the greatest things about this sport! Quote Share this post Link to post Share on other sites
The111 1 #21 February 10, 2004 I think you missed kallend's and dave's point. For simplicity, air is often assumed to be a continuum, and in most cases this is a somewhat adequate assumption. But it's still an assumption; air is NOT a continuum, and scaling/size of the object does matter, since the size of air molecules stays constant.www.WingsuitPhotos.com Quote Share this post Link to post Share on other sites
jumpingjoe 0 #22 February 10, 2004 For those of you who want to read this: http://hypertextbook.com/facts/JianHuang.shtml Interesting stuff here. Blue Skies Quote Share this post Link to post Share on other sites
