Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫  π  -¹ ² ³ °

You are not logged in.

## #1 Re: Help Me ! » Calculating Adjacent Distance from a Slope Distance Measurement » 2005-11-07 07:34:10

Thank you for the input.  I have seen the R=bv equation but I have not seen the other.  That one looks the most promising to date.  The v portion will prove to be difficult as a secondary function will need to be performed that needs to factor in the increasing vertical and diminishing horizontal speeds (the bike is powerless in midair) and also to include gravity with all of that to be continually updated as the bike travels through it's arc.  To add to the difficulty, the slope of the landing ramp needs to be factored in as well.

The good thing about it is I have real data to bounce off of the speed calculator as a data checker.  Distances of 30 feet to 300 feet, takeoff angles of 11, 16, 22 and 28 degrees, landing angles of 8, 12 and 14 degrees and speeds from 33 to 82 mph.

Again, thanks for the input.  I guess my next step is to take a class or two and figure these things out for myself so I don't have to keep bugging you folks.

Joe.

## #2 Re: Help Me ! » Calculating Adjacent Distance from a Slope Distance Measurement » 2005-11-06 17:21:54

Outstanding.  I put it together in an Excel spreadsheet with the ratio function you suggested and it works great.  Thank you so much for your help.  On to bigger and better things.

I am putting together a spreadsheet that will calcualte speeds for this type of jump and I am almost there.  The difficlut part is factoring in the wind resistance.  Plenty of ballistics formulas out there but none with air resistance.

Again, thank you for your persistance, much appreciated.

Thanks - Joe

## #3 Re: Help Me ! » Calculating Adjacent Distance from a Slope Distance Measurement » 2005-11-06 06:37:04

Thank you for the response, I'll be more patient this time.  I was unable to figure out how to attach my drawing that I'm sure would help a great deal.  Yes, I did get 127 for the adjacent of the large triangle.  I lost you at the point you stated that a new smaller triangle has been created that measures "up the slope 52'".  I came up with 54.6' up the slope as I calcualted 130' - 75'.  Like I say, I'm lost.

I'll try to make it a little more clear by giving the facts of the scenario.  This is real world - last Saturday, a motorcycle jumper jumped a claimed 310' 4" for the record.  This was measured by running a steel tape along the ground from the leading edge of the takeoff ramp to the leading edge of the landing ramp which measured 235' for the gap meaurement.  A mark was made on the landing ramp where the jumper had landed (on the 130' hypotenuse) and this was measured with a steel tape from the top of the landing ramp (28' tall oppostite side - corresponds to measurement taken along the ground from the takeoff to the landing ramps) with a distance of 75' 4" down the slope.  Since the actual distance of the jump should be measured along the adjacent only (from the leading edge of the takeoff to the corresponding point on the ground where he landed on the ramp), my argument is that the method used to measure the distance is incorrect.  I need to prove this with a formula that accurately determines the true distance travelled with the data gathered in the method that it was recorded.  Trig classes from over 20 years ago tells me they are wrong but I don't have the smarts to translate that into a formula.  He still has the record (previous record of 277.5' measured the same way) but I would like to see accurate measurements.

Thanks again,

Joe

(wish I had a nifty saying)

## #4 Re: Help Me ! » Calculating Adjacent Distance from a Slope Distance Measurement » 2005-11-03 12:23:34

I guess I'm no fun.  What am I missing here to make it fun enough to respond to???  Am I missing work performed to this point?

Thanks.

## #5 Help Me ! » Calculating Adjacent Distance from a Slope Distance Measurement » 2005-11-03 10:24:47

First Guess
Replies: 9

I can't quite figure out the formula required to determine the true adjacent side distance that corresponds to a measured distance down the slope of the hypotenuse when the overall opposite and hypotenuse sides lengths are known on a right triangle.  The opposite side is 28 feet tall, the hypotenuse is 130 feet long and the measured distance down the slope of the hypotenuse is 75 feet.  How do I derive the corresponding distance along the adjacent axis?

I managed to figure out the overall adjacent length with the known opposite and hypotenuse lengths but can't get that last part.

Any help at all would be most appreciated.  Thanks in advance.