raw 0 #1 January 28, 2006 Serious question, why do we fall at different rates? At school we where taught that everything falls at the same rate. e.g if you drop a tv and a 10 pence peice out of a window at the same time they will impact at the same time. I remember something about 64mph per second, per second. Its easy to understand the less area or more aerodinamic area you present to earth the faster you fall. What i don't understand is why big guys fall faster Than us lighter slow fallers. Is it just the natural arch of a big belly creating an aerodinamic shape? I was baffled the first time i saw a small lady put lead on to jump RW. Two years later I still havn't got my head around it!! Quote Share this post Link to post Share on other sites
MooChooser 0 #2 January 28, 2006 Its a matter of the surface area to weight ratio. Gravity exerts the same force on everything but not everything falls at the same rate unless youre in a vacuum. Short and fat probably means you fall fast Tall and skinny (like me)probably means you fall Slow. If youre a tall skinny slow faller, you can arch, allowing the air to pass you by more easily thereby exerting less drag on you. This helps you fall faster through the air. What falls faster, a ton of sponge or a ton of lead? the answers obvious because a ton of sponge is huge compared to the lead. Unless of course the lead is a sheet 1 atom thick or something, but you get the point. Quote Share this post Link to post Share on other sites
niu 0 #3 January 28, 2006 Everything fall at the same rate in a vacuum. Luckily air is present on this ball,which makes objects with a lot of mass and a relatively small frontal area fall faster than ojects with a lot of frontal area and less mass. That`s why slicksuits and lead are bad ideas for beer bellied men,besides the estetic aspects of course. Quote Share this post Link to post Share on other sites eeneR 1 #4 January 28, 2006 QuoteAt school we where taught that everything falls at the same rate. e.g if you drop a tv and a 10 pence peice out of a window at the same time they will impact at the same time. I seem to remember that theory pertains only to those items if they were in a vacuum I could be wrong, been awhile since I took physics...She is not a "Dumb Blonde" - She is a "Light-Haired Detour Off The Information Superhighway." eeneR TF#72, FB#4130, Incauto Quote Share this post Link to post Share on other sites MooChooser 0 #5 January 28, 2006 QuoteQuoteAt school we where taught that everything falls at the same rate. e.g if you drop a tv and a 10 pence peice out of a window at the same time they will impact at the same time. I seem to remember that theory pertains only to those items if they were in a vacuum I could be wrong, been awhile since I took physics... its probably true up to the point that one of them starts approaching terminal velocity. A can of beer and a tennis ball will both fall together for at least a story and probably more before the beer takes the lead Quote Share this post Link to post Share on other sites raw 0 #6 January 28, 2006 I would have thought that a big guy covering much more area thus offering more resistence to the relative wind would fall slower. I can't see how the weight plays that much of part, gravity having the same amount of pull on all of us and all that. I'm obviously wrong about this but thats how it plays out in my tiny brain. Quote Share this post Link to post Share on other sites OSOK 0 #7 January 28, 2006 QuoteQuoteQuoteAt school we where taught that everything falls at the same rate. e.g if you drop a tv and a 10 pence peice out of a window at the same time they will impact at the same time. I seem to remember that theory pertains only to those items if they were in a vacuum I could be wrong, been awhile since I took physics... its probably true up to the point that one of them starts approaching terminal velocity. A can of beer and a tennis ball will both fall together for at least a story and probably more before the beer takes the lead That's exactly right... they accelerate at the same rate, but they have different terminal velocities. I guess in classrooms they say "they reach the ground at the same time" simply because 6 feet isnt enough for them to reach terminal. Quote Share this post Link to post Share on other sites kelpdiver 2 #8 January 28, 2006 QuoteI would have thought that a big guy covering much more area thus offering more resistence to the relative wind would fall slower. I can't see how the weight plays that much of part, gravity having the same amount of pull on all of us and all that. I'm obviously wrong about this but thats how it plays out in my tiny brain. Since we are 3 dimensional, if you have a person like me that is twice the weight of some small gal, I might only have 50% more drag - being perhaps 12 inches taller, and a few inches wide, and a few inches deeper (which has limited effect). But the effect of gravity on me is still double. Quote Share this post Link to post Share on other sites raw 0 #9 January 28, 2006 If only i had not listened at school!! Quote Share this post Link to post Share on other sites matthewcline 0 #10 January 28, 2006 That will be a $1 beer fine, please. Next time use a soda of less popularity. A beer even if warm and old should never be wasted for scince, unless it is to see how much one can consume! In a proper scitific environment of course!An Instructors first concern is student safety. So, start being safe, first!!! Quote Share this post Link to post Share on other sites sd-slider 0 #11 January 28, 2006 Quoteunless youre in a vacuum This pic may explain the ideal situation for matched fall-rates. May be little too scientific, but, it does help explain a little....Anvil Brother #69 Sidelined with a 5mm C5-C6 herniated disk... Back2Back slammers and 40yr old fat guys don't mix! Quote Share this post Link to post Share on other sites Scoop 0 #12 January 28, 2006 Thanks, very nice diagram Picture paints a thousand words Quote Share this post Link to post Share on other sites JohnMitchell 14 #13 January 28, 2006 QuoteIf only i had not listened at school!! Nope, you should have listened more! They usually explain the "in a vacuum" with no wind resistance bit. Anyway, ever see a feather and a bowling ball fall together? Of course not, because of air resistance. Same thing with a big, fat jumper and a tiny, slender jumper, just not quite as extreme. I can't tell you how many whuffos have insisted on telling me that all jumpers fall at the same speed. Back in 1971, on one of the Apollo missions to the moon, one of the Astronauts dropped a feather and a hammer at the same time. Watching at home on TV, you could see that they both fell the same speed and hit the ground (moon) simultaneously, due to the lack of atmosphere on the moon, just like in the textbook. Science rocks! Quote Share this post Link to post Share on other sites Superman32 0 #14 January 28, 2006 MENTAL NOTE: Don't jump with a parachute in a vaccum Inveniam Viam aut Faciam I'm back biatches! Quote Share this post Link to post Share on other sites phoenixlpr 0 #15 January 29, 2006 See the 3rd law of motion by Newton: http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html QuoteIII. For every action there is an equal and opposite reaction. Force to accelerate m * g where m is the weight, g ~ 10 m/s^2 force equlas to it: r * A * v ^2 where r is coming from the shape, A is the area and v is the speed. When a jumper reach terminal velocity m * g = r * A * v ^ 2 Quote Share this post Link to post Share on other sites Trae 1 #16 January 29, 2006 in reply to "Serious question, why do we fall at different rates?" .................. FRICTION MAN / Surface area/ weight/lift /drag/thrust variablesetc etc I just love how an ant can land running from its terminal velocity. Quote Share this post Link to post Share on other sites Andy9o8 0 #17 January 29, 2006 QuoteI just love how an ant can land running from its terminal velocity. So can Spiderman. Bet you didn't know that. Quote Share this post Link to post Share on other sites kschilk 0 #18 January 29, 2006 QuoteQuoteI just love how an ant can land running from its terminal velocity. So can Spiderman. Bet you didn't know that. Cats too....but a slightly angled trajectory helps!"T'was ever thus." Quote Share this post Link to post Share on other sites kallend 1,625 #19 January 29, 2006 QuoteSee the 3rd law of motion by Newton: http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html QuoteIII. For every action there is an equal and opposite reaction. Force to accelerate m * g where m is the weight, g ~ 10 m/s^2 force equlas to it: r * A * v ^2 where r is coming from the shape, A is the area and v is the speed. When a jumper reach terminal velocity m * g = r * A * v ^ 2 That web site got the 2nd Law wrong. Newton did NOT write f=ma (contrary to popular belief), and f = ma is NOT Newton's 2nd law. Newton's 2nd law is "The change of motion is proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed" (Principia, Book 1) Newton used the word "motion" where we would now use "momentum". Acceleration (a) is not mentioned at all, neither is mass (m). Finally, since there is no air on the Moon, and hence no terminal velocity, are you implying that Newton's 3rd law doesn't apply there?... 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 Travman 6 #20 January 29, 2006 I was taught the bigger jumper has more inerita due to the weight. With the extra inertia the bigger jumper can push the air out of the way easier. Quote Share this post Link to post Share on other sites sd-slider 0 #21 January 29, 2006 QuoteI was taught the bigger jumper has more inerita due to the weight Who ya' callin' FAT!Anvil Brother #69 Sidelined with a 5mm C5-C6 herniated disk... Back2Back slammers and 40yr old fat guys don't mix! Quote Share this post Link to post Share on other sites Trae 1 #22 January 29, 2006 in reply to "So can Spiderman. Bet you didn't know that. " ....................... That's one my brother nose. Quote Share this post Link to post Share on other sites raw 0 #23 January 29, 2006 QuoteSee the 3rd law of motion by Newton: http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html QuoteIII. For every action there is an equal and opposite reaction. Force to accelerate m * g where m is the weight, g ~ 10 m/s^2 force equlas to it: r * A * v ^2 where r is coming from the shape, A is the area and v is the speed. When a jumper reach terminal velocity m * g = r * A * v ^ 2 Well, that cleared that up then. Quote Share this post Link to post Share on other sites phoenixlpr 0 #24 January 29, 2006 QuoteFinally, since there is no air on the Moon, and hence no terminal velocity, are you implying that Newton's 3rd law doesn't apply there? Why do you use NewtonIII in a case where is no reaction? Reaction is going to happen when the object touches the surface. NewtonIII is the case where an object is not the surface of the Moon. NewtonII should be use with an object over the Moon surface or moving with the 1st or 2st orbiting speed of the Moon. Quote Share this post Link to post Share on other sites Orange1 0 #25 January 29, 2006 There's a bit on this on Kallend's site - see http://www.iit.edu/~kallend/skydive/ and click on the "physics of skydiving" pptSkydiving: wasting fossil fuels just for fun. Quote Share this post Link to post Share on other sites Prev 1 2 Next Page 1 of 2 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
eeneR 1 #4 January 28, 2006 QuoteAt school we where taught that everything falls at the same rate. e.g if you drop a tv and a 10 pence peice out of a window at the same time they will impact at the same time. I seem to remember that theory pertains only to those items if they were in a vacuum I could be wrong, been awhile since I took physics...She is not a "Dumb Blonde" - She is a "Light-Haired Detour Off The Information Superhighway." eeneR TF#72, FB#4130, Incauto Quote Share this post Link to post Share on other sites
MooChooser 0 #5 January 28, 2006 QuoteQuoteAt school we where taught that everything falls at the same rate. e.g if you drop a tv and a 10 pence peice out of a window at the same time they will impact at the same time. I seem to remember that theory pertains only to those items if they were in a vacuum I could be wrong, been awhile since I took physics... its probably true up to the point that one of them starts approaching terminal velocity. A can of beer and a tennis ball will both fall together for at least a story and probably more before the beer takes the lead Quote Share this post Link to post Share on other sites
raw 0 #6 January 28, 2006 I would have thought that a big guy covering much more area thus offering more resistence to the relative wind would fall slower. I can't see how the weight plays that much of part, gravity having the same amount of pull on all of us and all that. I'm obviously wrong about this but thats how it plays out in my tiny brain. Quote Share this post Link to post Share on other sites
OSOK 0 #7 January 28, 2006 QuoteQuoteQuoteAt school we where taught that everything falls at the same rate. e.g if you drop a tv and a 10 pence peice out of a window at the same time they will impact at the same time. I seem to remember that theory pertains only to those items if they were in a vacuum I could be wrong, been awhile since I took physics... its probably true up to the point that one of them starts approaching terminal velocity. A can of beer and a tennis ball will both fall together for at least a story and probably more before the beer takes the lead That's exactly right... they accelerate at the same rate, but they have different terminal velocities. I guess in classrooms they say "they reach the ground at the same time" simply because 6 feet isnt enough for them to reach terminal. Quote Share this post Link to post Share on other sites
kelpdiver 2 #8 January 28, 2006 QuoteI would have thought that a big guy covering much more area thus offering more resistence to the relative wind would fall slower. I can't see how the weight plays that much of part, gravity having the same amount of pull on all of us and all that. I'm obviously wrong about this but thats how it plays out in my tiny brain. Since we are 3 dimensional, if you have a person like me that is twice the weight of some small gal, I might only have 50% more drag - being perhaps 12 inches taller, and a few inches wide, and a few inches deeper (which has limited effect). But the effect of gravity on me is still double. Quote Share this post Link to post Share on other sites
raw 0 #9 January 28, 2006 If only i had not listened at school!! Quote Share this post Link to post Share on other sites
matthewcline 0 #10 January 28, 2006 That will be a $1 beer fine, please. Next time use a soda of less popularity. A beer even if warm and old should never be wasted for scince, unless it is to see how much one can consume! In a proper scitific environment of course!An Instructors first concern is student safety. So, start being safe, first!!! Quote Share this post Link to post Share on other sites
sd-slider 0 #11 January 28, 2006 Quoteunless youre in a vacuum This pic may explain the ideal situation for matched fall-rates. May be little too scientific, but, it does help explain a little....Anvil Brother #69 Sidelined with a 5mm C5-C6 herniated disk... Back2Back slammers and 40yr old fat guys don't mix! Quote Share this post Link to post Share on other sites
Scoop 0 #12 January 28, 2006 Thanks, very nice diagram Picture paints a thousand words Quote Share this post Link to post Share on other sites
JohnMitchell 14 #13 January 28, 2006 QuoteIf only i had not listened at school!! Nope, you should have listened more! They usually explain the "in a vacuum" with no wind resistance bit. Anyway, ever see a feather and a bowling ball fall together? Of course not, because of air resistance. Same thing with a big, fat jumper and a tiny, slender jumper, just not quite as extreme. I can't tell you how many whuffos have insisted on telling me that all jumpers fall at the same speed. Back in 1971, on one of the Apollo missions to the moon, one of the Astronauts dropped a feather and a hammer at the same time. Watching at home on TV, you could see that they both fell the same speed and hit the ground (moon) simultaneously, due to the lack of atmosphere on the moon, just like in the textbook. Science rocks! Quote Share this post Link to post Share on other sites Superman32 0 #14 January 28, 2006 MENTAL NOTE: Don't jump with a parachute in a vaccum Inveniam Viam aut Faciam I'm back biatches! Quote Share this post Link to post Share on other sites phoenixlpr 0 #15 January 29, 2006 See the 3rd law of motion by Newton: http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html QuoteIII. For every action there is an equal and opposite reaction. Force to accelerate m * g where m is the weight, g ~ 10 m/s^2 force equlas to it: r * A * v ^2 where r is coming from the shape, A is the area and v is the speed. When a jumper reach terminal velocity m * g = r * A * v ^ 2 Quote Share this post Link to post Share on other sites Trae 1 #16 January 29, 2006 in reply to "Serious question, why do we fall at different rates?" .................. FRICTION MAN / Surface area/ weight/lift /drag/thrust variablesetc etc I just love how an ant can land running from its terminal velocity. Quote Share this post Link to post Share on other sites Andy9o8 0 #17 January 29, 2006 QuoteI just love how an ant can land running from its terminal velocity. So can Spiderman. Bet you didn't know that. Quote Share this post Link to post Share on other sites kschilk 0 #18 January 29, 2006 QuoteQuoteI just love how an ant can land running from its terminal velocity. So can Spiderman. Bet you didn't know that. Cats too....but a slightly angled trajectory helps!"T'was ever thus." Quote Share this post Link to post Share on other sites kallend 1,625 #19 January 29, 2006 QuoteSee the 3rd law of motion by Newton: http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html QuoteIII. For every action there is an equal and opposite reaction. Force to accelerate m * g where m is the weight, g ~ 10 m/s^2 force equlas to it: r * A * v ^2 where r is coming from the shape, A is the area and v is the speed. When a jumper reach terminal velocity m * g = r * A * v ^ 2 That web site got the 2nd Law wrong. Newton did NOT write f=ma (contrary to popular belief), and f = ma is NOT Newton's 2nd law. Newton's 2nd law is "The change of motion is proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed" (Principia, Book 1) Newton used the word "motion" where we would now use "momentum". Acceleration (a) is not mentioned at all, neither is mass (m). Finally, since there is no air on the Moon, and hence no terminal velocity, are you implying that Newton's 3rd law doesn't apply there?... 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 Travman 6 #20 January 29, 2006 I was taught the bigger jumper has more inerita due to the weight. With the extra inertia the bigger jumper can push the air out of the way easier. Quote Share this post Link to post Share on other sites sd-slider 0 #21 January 29, 2006 QuoteI was taught the bigger jumper has more inerita due to the weight Who ya' callin' FAT!Anvil Brother #69 Sidelined with a 5mm C5-C6 herniated disk... Back2Back slammers and 40yr old fat guys don't mix! Quote Share this post Link to post Share on other sites Trae 1 #22 January 29, 2006 in reply to "So can Spiderman. Bet you didn't know that. " ....................... That's one my brother nose. Quote Share this post Link to post Share on other sites raw 0 #23 January 29, 2006 QuoteSee the 3rd law of motion by Newton: http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html QuoteIII. For every action there is an equal and opposite reaction. Force to accelerate m * g where m is the weight, g ~ 10 m/s^2 force equlas to it: r * A * v ^2 where r is coming from the shape, A is the area and v is the speed. When a jumper reach terminal velocity m * g = r * A * v ^ 2 Well, that cleared that up then. Quote Share this post Link to post Share on other sites phoenixlpr 0 #24 January 29, 2006 QuoteFinally, since there is no air on the Moon, and hence no terminal velocity, are you implying that Newton's 3rd law doesn't apply there? Why do you use NewtonIII in a case where is no reaction? Reaction is going to happen when the object touches the surface. NewtonIII is the case where an object is not the surface of the Moon. NewtonII should be use with an object over the Moon surface or moving with the 1st or 2st orbiting speed of the Moon. Quote Share this post Link to post Share on other sites Orange1 0 #25 January 29, 2006 There's a bit on this on Kallend's site - see http://www.iit.edu/~kallend/skydive/ and click on the "physics of skydiving" pptSkydiving: wasting fossil fuels just for fun. Quote Share this post Link to post Share on other sites Prev 1 2 Next Page 1 of 2 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
Superman32 0 #14 January 28, 2006 MENTAL NOTE: Don't jump with a parachute in a vaccum Inveniam Viam aut Faciam I'm back biatches! Quote Share this post Link to post Share on other sites
phoenixlpr 0 #15 January 29, 2006 See the 3rd law of motion by Newton: http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html QuoteIII. For every action there is an equal and opposite reaction. Force to accelerate m * g where m is the weight, g ~ 10 m/s^2 force equlas to it: r * A * v ^2 where r is coming from the shape, A is the area and v is the speed. When a jumper reach terminal velocity m * g = r * A * v ^ 2 Quote Share this post Link to post Share on other sites
Trae 1 #16 January 29, 2006 in reply to "Serious question, why do we fall at different rates?" .................. FRICTION MAN / Surface area/ weight/lift /drag/thrust variablesetc etc I just love how an ant can land running from its terminal velocity. Quote Share this post Link to post Share on other sites
Andy9o8 0 #17 January 29, 2006 QuoteI just love how an ant can land running from its terminal velocity. So can Spiderman. Bet you didn't know that. Quote Share this post Link to post Share on other sites
kschilk 0 #18 January 29, 2006 QuoteQuoteI just love how an ant can land running from its terminal velocity. So can Spiderman. Bet you didn't know that. Cats too....but a slightly angled trajectory helps!"T'was ever thus." Quote Share this post Link to post Share on other sites
kallend 1,625 #19 January 29, 2006 QuoteSee the 3rd law of motion by Newton: http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html QuoteIII. For every action there is an equal and opposite reaction. Force to accelerate m * g where m is the weight, g ~ 10 m/s^2 force equlas to it: r * A * v ^2 where r is coming from the shape, A is the area and v is the speed. When a jumper reach terminal velocity m * g = r * A * v ^ 2 That web site got the 2nd Law wrong. Newton did NOT write f=ma (contrary to popular belief), and f = ma is NOT Newton's 2nd law. Newton's 2nd law is "The change of motion is proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed" (Principia, Book 1) Newton used the word "motion" where we would now use "momentum". Acceleration (a) is not mentioned at all, neither is mass (m). Finally, since there is no air on the Moon, and hence no terminal velocity, are you implying that Newton's 3rd law doesn't apply there?... 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
Travman 6 #20 January 29, 2006 I was taught the bigger jumper has more inerita due to the weight. With the extra inertia the bigger jumper can push the air out of the way easier. Quote Share this post Link to post Share on other sites
sd-slider 0 #21 January 29, 2006 QuoteI was taught the bigger jumper has more inerita due to the weight Who ya' callin' FAT!Anvil Brother #69 Sidelined with a 5mm C5-C6 herniated disk... Back2Back slammers and 40yr old fat guys don't mix! Quote Share this post Link to post Share on other sites
Trae 1 #22 January 29, 2006 in reply to "So can Spiderman. Bet you didn't know that. " ....................... That's one my brother nose. Quote Share this post Link to post Share on other sites
raw 0 #23 January 29, 2006 QuoteSee the 3rd law of motion by Newton: http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html QuoteIII. For every action there is an equal and opposite reaction. Force to accelerate m * g where m is the weight, g ~ 10 m/s^2 force equlas to it: r * A * v ^2 where r is coming from the shape, A is the area and v is the speed. When a jumper reach terminal velocity m * g = r * A * v ^ 2 Well, that cleared that up then. Quote Share this post Link to post Share on other sites
phoenixlpr 0 #24 January 29, 2006 QuoteFinally, since there is no air on the Moon, and hence no terminal velocity, are you implying that Newton's 3rd law doesn't apply there? Why do you use NewtonIII in a case where is no reaction? Reaction is going to happen when the object touches the surface. NewtonIII is the case where an object is not the surface of the Moon. NewtonII should be use with an object over the Moon surface or moving with the 1st or 2st orbiting speed of the Moon. Quote Share this post Link to post Share on other sites
Orange1 0 #25 January 29, 2006 There's a bit on this on Kallend's site - see http://www.iit.edu/~kallend/skydive/ and click on the "physics of skydiving" pptSkydiving: wasting fossil fuels just for fun. Quote Share this post Link to post Share on other sites
