syntax 0 #1 November 10, 2006 I was just wondering how you guys, and girls work out the height of lower objects.Do you drop a rock and count or do you use a more accurate alti then say a altimaster.Also if you drop a rock and count, is there a basic formula you use to calculate the height.Or is it more like,the rock fell for 7 seconds, I'll delay for 3... or something! This is just something I have always been curious about. Thanks.------------------------------------skydiving...the grounds the limit! Share this post Link to post Share on other sites
dbagdrew 0 #2 November 10, 2006 Many people use laser range finders. Usually accurate to +- 1 meter.Education: that which reveals to the wise, and conceals from the stupid, the vast limits of their knowledge. - Mark Twain Share this post Link to post Share on other sites
syntax 0 #3 November 10, 2006 Ah, that makes sense!I thought it would be hard to work out 326 feet or whatever on something like my altimaster.No dropping rocks either eh?------------------------------------skydiving...the grounds the limit! Share this post Link to post Share on other sites
DrewEckhardt 0 #4 November 10, 2006 Quote Also if you drop a rock and count, is there a basic formula you use to calculate the height. Velocity = acceleration * time Integrating you get distance = 1/2 acceleration * time^2. Acceleration due to gravity is 32 feet/seconds^2 or 9.8 meters/seconds^2 so Height = 16 feet * t^2 or 4.9 meters * t^2 with t expressed in seconds This produces a result that's too high for taller objects because acceleration is not a constant - it decreases as velocity increases since drag goes up and acts opposite gravity. Share this post Link to post Share on other sites
mfob 0 #5 November 10, 2006 The pull of gravity although is different in all places. For instance, here in Idaho it is 9.8 m/sec. I know it is not that different in most cases but it helps sometimes. Density of air is a factor too. $.02 Share this post Link to post Share on other sites
Calvin19 0 #6 November 10, 2006 Quote The pull of gravity although is different in all places. For instance, here in Idaho it is 9.8 m/sec. I know it is not that different in most cases but it helps sometimes. Density of air is a factor too. $.02 gravitational force is not equal in all exits, correct. but there is NO way a jumper with ANY commercialy available equipment could tell the differences between the gravitation forces of different places. and air friction is almost nill difference at altitude, especialy low jumps where its all about acceleration. and super especialy because that measurment method only works until air friction becomes a factor. Share this post Link to post Share on other sites
base736 0 #7 November 10, 2006 Quote No dropping rocks either eh? Here's the problem. Say you drop a rock. You dropped it vertically, right? If you lob it (maybe you have to clear some structure) enough to give it just a couple of extra inches above where you let it go, you'll add 1/10 second. Anyway, you record 3.3 seconds to impact. Maybe you're off by 1/10 of a second (if you're a ninja and you're using a stopwatch). If you went off of the sound of the rock hitting, you'll want to remember that sound will take 1/10 of a second to cover each 100 feet back to you. That can add up. At 3.3 seconds, the rock is moving 105 ft/second. That means +/- 10 feet of error for every 1/10 of a second you're off. Altogether, maybe you're lucky and there's 2/10 of a second of error in your number. Is that significant? Could be if you were planning to freefall an object that you now know to be between 155 and 195 feet. Laser rangefinders are cheap and give 1-yard accuracy. Rocks are even cheaper, but you probably shouldn't count on them to give better than 20 or 30 feet of accuracy even for a low jump. Rock drops only get worse from there. Edit: Stupid typos... Share this post Link to post Share on other sites
dcm 0 #8 November 10, 2006 i tell my friends to go first Share this post Link to post Share on other sites
grue 1 #9 November 10, 2006 Quote i tell my friends to go first Officially my favourite "first post" in a long time cavete terrae. Share this post Link to post Share on other sites
base_rigger 0 #11 November 10, 2006 I use maggot, so far so good.You know you have a problem when maggot is the voice of reason at the exit points Share this post Link to post Share on other sites
mtnlion667 0 #12 November 10, 2006 I've counted ladder rungs. dropped rocks. and my favorite, just said fuck it... what's the worst that could happen. that ended up w/me jumping into a vally with monster boulders for a LZ and walls nearly too steep to climb out of. So I took the bridal off and rolled it over for a second one.... it's a wonder any of us are still alive "Faster, faster, until the thrill of speed overcomes the fear of death." Hunter S. Thompson Share this post Link to post Share on other sites
Mikki_ZH 0 #13 November 10, 2006 If you just want to know the hight of the object then a laser is good. But for an subtermanal E that comes out a bit it is defently better to throw rocks. Then you also know if it is jumpable... An example: First you throw a rock and hear impact after 3 seconds, then you throw it a bit harder and hear impact after 8 seconds, then you go shopping for metal, wood, bolts and so on, then you go back to the jump and build a nice ramp, then you drop another rock and hear impact after 8 seconds without having to toss the rock, then you jump... -------------------------------- This is how BASE1007 evaluates an E...Michi (#1068) hsbc/gba/sba www.swissbaseassociation.ch www.michibase.ch Share this post Link to post Share on other sites
andyflylife 0 #14 November 10, 2006 Quote Many people use laser range finders. Usually accurate to +- 1 meter. On the subject of range finders...Are you able to instanly calculate the top height of any object you point it at? or is it a case of working out a distance away from it when stood at 45 degrees to the top? "swooper 24/7, 365!" ME on Myspace My Project playlist Share this post Link to post Share on other sites
Calvin19 0 #15 November 10, 2006 the laser measures distance, not height. I have done calculations of angle/distance shit, but i failed college algebra twice, so i try to get to the base of the object. funny, i can do all the seemingly more complex math for Frasca, but i cant get college algebra down. oh well. anyone know where i can buy a degree? not kidding. Share this post Link to post Share on other sites
tfelber 0 #16 November 10, 2006 The range finder gives you the distance from where it's at to the object it's pointing at. If you are som distance from the base of the object you will need to use the pathagorean theorem to calculate the actual height. Share this post Link to post Share on other sites
jools 0 #17 November 10, 2006 www.algebra.com/calculators/geometry/pythagorean.mpl"If you don't like it then fuck off" BASE 621 Share this post Link to post Share on other sites
dbrutherford 0 #18 November 10, 2006 Quote anyone know where i can buy a degree? not kidding. When I get my two Bachelor's done, you can buy one of my Associates from me.... They aren't worth a damn anyways. I had to go back to school because I couldn't find a job with them. Algebra really isn't that hard. Try differential calculus. Now that class sucked! Share this post Link to post Share on other sites
magot 0 #19 November 10, 2006 how about this u have 60 jumpe the only thing u should be thinking about is getting your c- license silluy rabbit base is n ot for kidsTOSS MY SALAD I'm an invincible re-tarded ninja derka derka bakala bakala muhammad jihad 1072 Share this post Link to post Share on other sites
Calvin19 0 #20 November 10, 2006 i need a bachelor -SPACE- Share this post Link to post Share on other sites
magot 0 #21 November 10, 2006 u mean a bacheler party with lots of hookers yah thats a great ideaTOSS MY SALAD I'm an invincible re-tarded ninja derka derka bakala bakala muhammad jihad 1072 Share this post Link to post Share on other sites
dbrutherford 0 #22 November 11, 2006 I like hookers..... prostitutes charge too much! Share this post Link to post Share on other sites
