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Hey guys, I have been wondering how height of an object is determined by dropping rocks from the object, OR if any other methods is used. I did try to use the search function and couldnt find a thread on the subject. thanks in advance!

http://www.gravitycalc.com/
This is a good site for rock drop.
Also I would recommend purchasing a laser range finder for more accurate heights.

either i dont understand the data inputs how to, or that is way wrong.the link you posted. i get 791m for 12,7 secs from the link of gravitycalcs website. my calc is 489m. because maybe they dont include surface area and weight (mass).

A2+B2=C2

Check out:
http://www.dummies.com/how-to/content/how-to-calculate-time-and-distance-from-accelerati.html

When looking at the link above acceleration(a)=gravity(g)=9.8m/s^2

But that is Pythag. Has no thing to do with acceleration.
I took a readings with gps and a inclinometer and used the pythag formula to measure altitude.
I am sure that i made no mistakes.
Old school skydiving had 10secs for the first 1000ft, 5secs for the additional 1000 formula. 300m diff over 13seconds? I am getting too mathy. I almost shut up now.
tcs

http://naturelovesmath-en.blogspot.de/2011/06/niels-bohr-barometer-question-myth.html

They're falling in a vacuum... drag just adds needless complexity to the equation, because it varies with altitude (among other things).

A range finder is always best...https://www.youtube.com/watch?v=9ie8VEtQHmE

For old school types, here's a rough guide, kindly provided by Johnny Utah.
http://johnnyutah.com/freefallchart1.html Note, these are based on freefall from an undeclared altitude ASL, and an undeclared frontal area to mass ratio (and coefficient of drag)... YMMV.

Do you have a photo of the other side? I'd like to see which model you're suggesting. I'd hate to have an off-heading opening...

~ Chris

i appreciate your response. i do have some understated exp with high and low jumps. drag can be a very important factor. on stratos type of jumps when one is going trans sonic. But that is not the topic here. my team can give an adequate solution to answer. from highest to lowest jumps. figuring the height is easy peasy.
tcs

haha. just make sure carrying a tape measure doesn't mess up your body position.

wow, i'm already lost on what this thread was about. i thought it was about "calculating" height. probably one of the silliest questions i've seen on this forum in some time. not only is it super obvious (so long as you don't lack common sense), but it is quite irrelevant without context.

i posted the tape measure picture, because that is an actual method to measure height of one class of BASE objects.


next question.

i did a long post about Niels Bohr. i dont see it posted. maybe prob with interweb connection.

 calculate the height of an object, with consideration to acceleration, use the following formula, its bombproof!!!

first, calculate total impedance Zt

then figure out capacitive reactance, and subtract that from the sum of the difference of two squares, and divide that by the formula for inductive reactance. then multiply that by the original impedance formula and youre styled!!!!

Sounds like a pretty big capacitor

Wow you guys have measuring tapes! That level of technology hasn't made it's way to SA yet, so I just tie reeds together and use the average reed height multiplied by the number of reeds to calculate height. 3rd world problems

Crack rocks work the best for rock drops. Kinda pricey though. But If i have to use one i am jumping regardless so its pointless to drop them in the first place. Just use your depth perception and word of mouth. The forest trolls can see you standing up there if you wait to long they will throw rocks at you.

i know this formular. but it didnt comp the drag. so i used an resistor. it was futile ;-)
tcs

Why the hell would you want to use formulas? They have skyjumps for that shit.
For impact height, it's either Ok, or it isn't.
As for total height, no point in numbers there as well, just pull 2 seconds after you shit yourself

Not sure how the rock drop thing really works personally, but if you have a little $$ laying around buy a cheap range finder from a golf shop (Amazon has them cheaper) and laser sight your object. Bushnell makes some pretty savvy ones on the less expensive side (150ish), they also make ones that account for tilt (upward looking) to give you a more accurate measurement for very tall objects.

A short vid might help
http://m.youtube.com/watch?v=9ie8VEtQHmE

The taller it is the more room for error, right?

Meaning, if you THINK it is 150 feet and it turns
out to actually really be 142 feet it might matter,
But if you thought a 1200 antenna was 1100, OR
if your 900 footer is really 946' does it matter?

My standard advice:
If you got money to burn, get a nice one, but any
working (read: used/cheap/ebay) range finder
is fine more most objects & most BASE jumps.

Down side to cheap:
they are less accurate, and don't light up so you
have to either recon during the day or scan to a
light source after you have taken your reading.