answer me this..
Begining speed 270.51mph
max speed 325.96
first 340 feet is done in 0.785 seconds
second leg of 320 feet is done in .678 seconds.

Total time for 660 feet is 1.463 sec

So what is the speed at the end of the first leg

 

Not really. It's a ratio that changes as the car moves. In your example, if the speedometer is 10% off [for example] then you will be doing 44MPH at an indicated 40. You'll be doing 88MPH at an indicated 80, 110MPH at 100, etc... That is an example of a linier formulation.

Wind resistance is a good example of a non-linier formulation. [In this example I'm leaving out thousands of variables for simplicities sake] 10 HP might overcome 20MPH winds. It might take 24HP to overcome 40MPH winds. Maybe 39HP to handle 60MPH winds and 56HP to take on 80MPH of wind resistance. Linier calculation of the resistance might look like 10hp to 20mph, 20hp to 40mph, 30hp for 60, and 40 for 80 MPH. Wind resistance multiplies exponentially, not linierly. So even if 10HP overcame 20 MPH winds, and 40HP overcame 80 MPH winds, 80HP would not handle 160MPH winds; it would take exponentially more power. How much more would depend on all those valiables that I left out in the beginning(i.e. Drag, rolling resistance, altitude, air density, tempurature, etc....)

 

What does this have to do with our word problem? Is this a test of my math skills? Why didn't you simply state that the time for 330 feet was .7315, in other words half the time of the 660ft. Was this some silly attempt to try to confuse me? I don't need a spread sheet to calculate the speed at a particular distance if I use a constant rate of acceleration. I know that I gain .0840151 MPH for every foot that I travel, based on your formula.

297.39483 is your answer, but your using a constant acceleration rate and times that were not given in the original word problem.

Please, stop, I graduated already, no more tests, I can't handle it. [img]i/expressions/face-icon-small-wink.gif[/img]

BTW- your times at 320' and 340' are not coinciding with your acceleration rate. Your time to distance for the first leg is identicle to your time to distance for the second leg. They would be based on a constant speed that we know can't be true. Trust me, your way behind on the math. I'm done with the tutoring.

 

If we had such complete information for launching satellites, there would be no need for thrusters to adjust the position of geosynchronous satallite. It would always be in the exact position that we calculated it should be. Since you are suggesting that the calculations are so far off, why don't you provide us a calculation that shows how far off they are. When you can do that, you will be in a position to say they are far off.

The engineers cannot get the math right? Not sure where this is comming from. I am not aware of dynamometers being somehow tied to calculations that Yamaha does for a Vmax. There is no chassis dyno that any of the big three own that somehow is governed by the mathematics developed for a Yamaha Vmax. Maybe you would like to elaborate on this. My discussion about chassis dynos was that the simulations are accurate to some degree of accuracy, not that the engineers are so stupid that they need to put a fudge factor in to get it right. That is ridiculous.

All calculations are based on assumption. And based on those assumptions, the math is certainly correct. It is funny that you are constantly complaining about the calculation cannot be made, but you provide no calculations or proof yourself. As a matter of fact, the information you give us is not correct. You said that the fueler clutch slips thoughout the quarter mile, but is doesn't. You say no dyno can hold the 8000hp of the fueler engine, but as we have seen we can write a check and buy one off the shelf. It is not clear that you understand how a fueler engine is controlled during the run, but you complain about my analysis.

 

Is your name really Don Johnson?[img]i/expressions/face-icon-small-happy.gif[/img]

 

Bryce, are you sure what side of the fence you are on about this issue? The fact that satalites have boosters to adjust position helps make my point. Despite the fact that they have much more complete information to base their calculation off of, they still know that it's not going to be completely accurate due to certain variable that they don't know. In accordance with your possition on the word problem, they should be able to calculate the exact possition and orbit and not be off in any way. My possition is that we don't have enough info to be correct and that the calculations are simply a hypothosis(a fancy name for and edjucated guess).

OH my gosh Bryce, if your not aware of it, it must not be true! The chassis dyno was invented by a man named Mark Dobeck. He created the company named Dynojet. In an interview with Jeff Hartman, Mr. Dobeck stated that he ordered his chief engineer to 'doctor" the math so that a '85 Yamaha V-Max would show 120HP instead of the 90HP that the standard formula was coming up with. The 120 number was chossen based on the Yamaha advertized HP rating at the time of 145HP and the existing torque cell engine dyno's that showed an average of around 120HP. This final "arbitrary" number-fudge was and is the basis for all chassis dyno ratings. This information is per the March '06 issue of Hot Rod magazine, page 80-82. If this is not correct, Mr. Hartman and Primedia Publishing are looking at a good bit of trouble. Is that the eloboration you were looking for? It's so rediculous that one of the biggest automotive magazines in the country printed it just a few months back. Baybe they should have checked with your all-knowing sorce from some other forum, just to disprove the inventor.

I'm stating that we have incomplete information to calculate the information asked for. Now if I could calculate haw far off you are, then I would have to be able to calculate the exact correct answer. No one has any idea how far off you are. You have as good of a shot at being correct as any guess. As I stated before, making assumptions is not the same as adding information.

I have looked, first hand, at the on-board telemetry of a top fuel dragsters run. This is were I gathered my information about the clutch slipping throughout the entire run. I will admitt that in some cases, if the track can handle it, the clutch may reach lock up befor the 1/4 mile mark, but that is the exception and not the rule. I understand that your sorce from some other forum must be much more accurate than my first hand information, but I'll stick with what I've seen for myself.

As for the dyno, pick one story and stick with it. First you stated that one could be made to work, now you say it's just a matter of writing a check. If a top fuel car can be tested on a dyno, I challenge you to show me proof. Find an exact HP output for any top fuel car. Better yet, find me a dyno chart. Post the link to one of those, and I'll gladly admitt I was wrong and appologise. I've stated the sorce for my dyno information, now show me yours.

The problem is that math is an absolute, it's NOT based on assumptions. It's either right or it's wrong. There is no inbetween of math. 1+1=2, not somewere around 2. Not 3 because we were not sure it 1 was actually 1. If you are claiming to solve a problem with math, you must have an absolute answer. If the answer isn't absolute, the math isn't solved. That is why when you solve for variables in an algebraic formula, it's called a "proof". The more you try to prove yourself correct, the less intelligent you seam. Especially with your "off the shelf" 8000 HP chassis dyno that can test a top fuel car.

 

A seach of the us Patent office shows a patent for a chassis dyno dated 1976. So I am not sure what 1985 has to do with the invention of chassis dynos. Chassis dyno There are many more, but this one also includes road load simulation.

So if you know of the on board telemetry, then post it so we can see how close we are. Seems to me if you can't say how far off a calculation is, you really have no position of argument.

 

You have to write a check to buy the dyno. Don't know maybe they will accept Visa. Give them a call. Here is the link to the dyno: Schenck D6300-1. This dyno is rated 6300kw or 8400hp. I would suggest one on each wheel, that way you don't need a gear reduction unit. I will be waiting for your apology.

 

Tell me what 1/3 is?? Is it 0.3 or 0.33 or 0.333 or 0.3333.. Not sure.. it is not exact.

Tell me what velocity is? We know it as the derivative of the position function. The derivative is defined as the limit of the delta position divided by the delta time as the delta time goes to zero. Doesn't sound too exact to me.

Tell me how fast your car is going. Is it going 50 mph or 50.1 or 50.12 or 50.123. Doesn't sound to exact to me.

 

While that is a chassis dyno, if you read about it you will find it's purpose. Is was designed to provide a load to simulate road conditions, not to measure HP. It does take a power measurement to determine the load to apply, but that measurement is descibed as a secondary purpose and not expressed in any common way. In actuallity, it method of applying a load has since proven to be unreliable as it uses a disk brake that has shown to change drag co-efficient as it heats up. Modern load control dyno's use a watter brake or eddy-current for load. While you did your research to find a dyno, you did nothing to disprove my statements. The infomation you provided has no relavence to our "discussion". It simply showed that Mr. Dobeck is not the only person to invent a chassis dyno, I will concide that point although I'm not sure of it's importance.

My entire point has been that you can't prove how close or far off your calculations are! What part of that do you fail to understand! If you retained what you read, I stated something along the lines of you could be as close as any guess. I MAINTAIN THAT KNOWONE CAN DETERMINE HOW FAR OFF YOUR CALCULATIONS ARE BECAUSE THEY CAN NOT CALCULATE THE CORRECT ANSWER! Besides, your said this is a discusion, when I called it a "pissing match", now it's an argument?