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I am posting this on behalf of Rich Butts and team 1511.
"The spreadsheet uses macros for the calculations. That means Excel's
security needs to be set to medium or less to open the file.
I've pencil whipped the spread sheet's appearance and added to the VBA
code. It's all based o...
I am posting this on behalf of Rich Butts and team 1511.
"The spreadsheet uses macros for the calculations. That means Excel's
security needs to be set to medium or less to open the file.
I've pencil whipped the spread sheet's appearance and added to the VBA
code. It's all based on the original calculations found on the net by
Mike O'brien.
This version...
- Takes english units as input and displays the metric units.
- Calculates the ball density.
- Shows the vertical location of the target's centerline.
- Includes a vertical location input for the launcher.
- Accommodates the difference between the original spread sheet's
trajectory result and FIRST's claim of poof-ball travel for given
launch conditions (35ft @ 12m/s & 30 deg. launch)
- Otherwise, I simply prettied it up a little and explained the
plotted data's meaning.
Rich Butts"
original spreadsheet: http://www.people.virginia.edu/~rjr/modules/xls/projectile/
original author is Robert J. Ribando.
Attached Files
-
Projectile motion Spreadsheet
1138121118projmotn_rb.xls
download file
uploaded: 01-24-2006 11:45 AM
filetype: xls
filesize: 357.5kb
downloads: 1082
Discussion
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02-08-2006 01:19 PM
R. J. Ribando
Re: White Paper Discuss: Projectile motion Spreadsheet
The modified spreadsheet as posted has a value in it for air of .00001536 kg/m^3, which is essentially a vacuum. The correct value given in my original spreadsheet is 1.19 kg/m^3 (approximately for sea level). Thus this modified spreadsheet does not contain any air drag - try adding wind to it and you'll see that there is no change in the trajectory. A strong wind in the negative direction should blow the projectile backwards! I don't know what a poof ball is, but I'd guess it probably has a lot of drag and that's why you had to fudge to match that experimental value.
If you really intend to ignore air drag, then get out your high school physics book and a piece of paper and pencil, because the solution for the projectile problem without air drag doesn't require the fancy numerical scheme implemented in this program!
rjr
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