# Practical Daily question \[about jumping off a building\] **URL:** \ **Category:** Factual Questions\ **Created:** [May 11, 2009, 6:29pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068 "2009-05-11T18:29:40Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Shot\_From\_Guns](https://avatars.discourse-cdn.com/v4/letter/s/ccd318/32.png) [@Shot\_From\_Guns](https://boards.straightdope.com/u/Shot_From_Guns)\ **Post date:** [May 12, 2009, 5:18pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/21 "2009-05-12T17:18:35Z")
And the OP didn’t mention any wind, which I expect they would have were there any, since you can’t account for it if you don’t know (a) that it exists and (b) which direction it’s coming from. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 12, 2009, 5:25pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/22 "2009-05-12T17:25:17Z")
> [@](#): > > Second thing I’ve noticed is that from above is that the two answers were a little bit different. 21.6 ft. and 24.2 ft? Is that difference to account for the width of the woman. Probably because they were using different figures for the height of the building. Not all stories are created equal. ---
**Author:** ![Hadrian\_s\_Wall](https://avatars.discourse-cdn.com/v4/letter/h/58956e/32.png) [@Hadrian\_s\_Wall](https://boards.straightdope.com/u/Hadrian_s_Wall)\ **Post date:** [May 12, 2009, 5:52pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/23 "2009-05-12T17:52:14Z")
> [@glee](#): > > This is too easy. > > Assume there’s a treadmill on the roof … how fast do you have to run then? > > What? I was ambiguous on wind, and other factors, b/c Well, I’m a bio major, don’t know too much about them math stuff. But the assumption is that sure there’s wind, but not enough to make a big difference. And no, there’s no vacuum, that would blow way too hard 😉 Further, I doubt jumping off makes a difference, it only would matter to how far out you go, I think? The V0 at leap is the same, because the manbomb creates a organic quadratic equation 🙂 ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [May 12, 2009, 5:59pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/24 "2009-05-12T17:59:08Z")
> [@kunilou](#): > > If you have to land horizontally, at what point are you measuring the height of the fall – from the manbomb’s feet, his waist, his head? > > Does the manbomb simply lean forward until he tips off his perch, or does he propel himself? > > Furthur study is indicated. I expect some jumpers might actually leap upwards a bit while departing the roof, so that would need to be calculated. And if the manbomb leans forward until toppling, that would also slow the acceleration for several early moments. I imagine you would make these measurements from the center of gravity of the manbomb. The body would rotate around the center of gravity as it leveled, though the actual impact point would probably not be at exactly that height. It’s even possible clothing would add another variable – parachute pants, for example. 😛 ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [May 12, 2009, 6:05pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/25 "2009-05-12T18:05:02Z")
> [@McLuhan's Thunder](#): > > … > And no, there’s no vacuum, that would blow way too hard 😉 > > … Vaccuums don’t blow. They suck! ---
**Author:** ![Hadrian\_s\_Wall](https://avatars.discourse-cdn.com/v4/letter/h/58956e/32.png) [@Hadrian\_s\_Wall](https://boards.straightdope.com/u/Hadrian_s_Wall)\ **Post date:** [May 12, 2009, 6:16pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/26 "2009-05-12T18:16:36Z")
> [@Boyo\_Jim](#): > > Vaccuums don’t blow. They suck! Nope, vacuums blow, because the observed behavior of them “sucking” is actually because there is a depressurization of the opposite side. With the less air pushing up against the barrier in between, the higher pressure pushes in the opposite direction. I hope I’m being clear when I write, but then again, I probably don’t know what I’m talking about either ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [May 12, 2009, 6:23pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/27 "2009-05-12T18:23:35Z")
> [@Shot\_From\_Guns](#): > > I highly doubt wind resistance will play anything but a negligible role when you’re only falling 600 feet. Well, your calcs in post #2 yield a final velocity around 196 ft/sec (= 133 mph). This is a bit more than terminal velocity for a skydiver in a stable belly-down position - so the force on a body at that speed is approximately equal to its weight, which I’d submit is more than a negligible effect. ---
**Author:** ![Hadrian\_s\_Wall](https://avatars.discourse-cdn.com/v4/letter/h/58956e/32.png) [@Hadrian\_s\_Wall](https://boards.straightdope.com/u/Hadrian_s_Wall)\ **Post date:** [May 12, 2009, 6:25pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/28 "2009-05-12T18:25:25Z")
> [@Xema](#): > > Well, your calcs in post #2 yield a final velocity around 196 ft/sec (= 133 mph). This is a bit more than terminal velocity for a skydiver in a stable belly-down position - so the force on a body at that speed is approximately equal to its weight, which I’d submit is more than a negligible effect. 113 mph or 120 mph±13? hehe ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [May 12, 2009, 6:34pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/29 "2009-05-12T18:34:32Z")
> [@McLuhan's Thunder](#): > > Nope, vacuums blow, because the observed behavior of them “sucking” is actually because there is a depressurization of the opposite side. With the less air pushing up against the barrier in between, the higher pressure pushes in the opposite direction. I hope I’m being clear when I write, but then again, I probably don’t know what I’m talking about either Pressure pushes, vaccuum sucks. Maybe that’s wrong. Pressure presses, vaccuums do not press back. So while vaccuums may not suck, they certainly don’t blow. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [May 12, 2009, 6:35pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/30 "2009-05-12T18:35:23Z")
I found this [freefall calculator](http://keisan.casio.com/has10/SpecExec.cgi) which claims that a 72-kg man falling 601 ft through air will take about 10% longer to hit the ground than he would in a vacuum. ---
**Author:** ![Shot\_From\_Guns](https://avatars.discourse-cdn.com/v4/letter/s/ccd318/32.png) [@Shot\_From\_Guns](https://boards.straightdope.com/u/Shot_From_Guns)\ **Post date:** [May 12, 2009, 6:58pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/31 "2009-05-12T18:58:24Z")
> [@Xema](#): > > I found this [freefall calculator](http://keisan.casio.com/has10/SpecExec.cgi) which claims that a 72-kg man falling 601 ft through air will take about 10% longer to hit the ground than he would in a vacuum. 10% longer would mean that he should jump when she’s 26.6 feet away. If your freefall calculator is correct, that would not be a completely negligible difference. Of course, I’m sure he can aim in flight, too. ---
**Author:** ![Hadrian\_s\_Wall](https://avatars.discourse-cdn.com/v4/letter/h/58956e/32.png) [@Hadrian\_s\_Wall](https://boards.straightdope.com/u/Hadrian_s_Wall)\ **Post date:** [May 12, 2009, 11:57pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/32 "2009-05-12T23:57:36Z")
> [@Shot\_From\_Guns](#): > > 10% longer would mean that he should jump when she’s 26.6 feet away. If your freefall calculator is correct, that would not be a completely negligible difference. > > Of course, I’m sure he can aim in flight, too. You can? I assumed that pretty after you fall, you go straight down, accelerating at the same time. Until you reach terminal velocity, that is. So how does one go about doing this aerial acrobatics? Suggestions? And, as I originally forgot in the OP, would manbombing, make a good first impression? And when do I deploy the parachutes, gotta make this safe 🙂 ---
**Author:** ![Hadrian\_s\_Wall](https://avatars.discourse-cdn.com/v4/letter/h/58956e/32.png) [@Hadrian\_s\_Wall](https://boards.straightdope.com/u/Hadrian_s_Wall)\ **Post date:** [May 12, 2009, 11:58pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/33 "2009-05-12T23:58:41Z")
Okay, relatively safe… ---
**Author:** ![Kent\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kent_clark/32/105_2.png) [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)\ **Post date:** [May 13, 2009, 12:09am UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/34 "2009-05-13T00:09:22Z")
> [@McLuhan's Thunder](#): > > And, as I originally forgot in the OP, would manbombing, make a good first impression? It would certainly make a striking one. ---
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [May 13, 2009, 12:29am UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/35 "2009-05-13T00:29:29Z")
> [@AskNott](#): > > . Nobody meets cute by jumping off a building. Sheesh. [Almost nobody.](http://www.azchords.com/c/christinelavin-tabs-22651/dorisandedwin-tabs-212268.html) ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [May 13, 2009, 1:07am UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/36 "2009-05-13T01:07:42Z")
Edited thread title to indicate subject. Colibri General Questions Moderator ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [May 13, 2009, 1:21am UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/37 "2009-05-13T01:21:43Z")
> [@McLuhan's Thunder](#): > > I assumed that pretty after you fall, you go straight down, accelerating at the same time. Until you reach terminal velocity, that is. As a skydiver’s speed increases, so does maneuverability. It’s obviously best at terminal velocity, but at even half that there’s some control. (In rough terms, maneuverability is proportional to speed squared.) ---
**Author:** ![Hadrian\_s\_Wall](https://avatars.discourse-cdn.com/v4/letter/h/58956e/32.png) [@Hadrian\_s\_Wall](https://boards.straightdope.com/u/Hadrian_s_Wall)\ **Post date:** [May 13, 2009, 3:49am UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/38 "2009-05-13T03:49:49Z")
> [@Xema](#): > > As a skydiver’s speed increases, so does maneuverability. It’s obviously best at terminal velocity, but at even half that there’s some control. (In rough terms, maneuverability is proportional to speed squared.) So if she tried to jump out of the way, you can correct? would there be enough time? ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [May 13, 2009, 4:24am UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/39 "2009-05-13T04:24:47Z")
> [@McLuhan's Thunder](#): > > So if she tried to jump out of the way, you can correct? would there be enough time? Unfortunately, her maneuverability will be much better than yours. ---
**Author:** ![Shot\_From\_Guns](https://avatars.discourse-cdn.com/v4/letter/s/ccd318/32.png) [@Shot\_From\_Guns](https://boards.straightdope.com/u/Shot_From_Guns)\ **Post date:** [May 13, 2009, 3:00pm UTC](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068/40 "2009-05-13T15:00:49Z")
Let’s be honest, though, how many of us scan the air above our heads for falling men as we walk past 40-story buildings? [Previous page](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068.md?page=1) [Next page](https://boards.straightdope.com/t/practical-daily-question-about-jumping-off-a-building/496068.md?page=3)