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150 Comments
Fossils, one of those pesky things that disprove creationist’s mythological belief the planet is 6,000 years old.
Bacterial Biofilms As Fossil Makers
ScienceDaily (Nov. 24, 2008) — Bacterial decay was once viewed as fossilization’s mortal enemy, but new research suggests bacterial biofilms may have actually helped preserve the fossil record’s most vulnerable stuff — animal embryos and soft tissues.
A team of 13 scientists led by Indiana University Bloomington biologists Rudolf and Elizabeth Raff found that the invasion of dying embryo cells by bacteria — and the subsequent formation of densely packed bacterial biofilms inside the embryo cells — can completely replace embryo cell structure, generating a faithful replica of the embryo. The scientists call this formation a “pseudomorph,” a model of the embryo made of bacteria. Their report will appear online via the Proceedings of the National Academy of Sciences “Early Edition” as early as Nov. 24.
More real science, not creationist myth at:
http://www.sciencedaily.com/releases/2008/11/081124174859.htm
Here is a problem given at a recent Scholars Bowl contest, that none of the contestants, who were comprised of some of our best and brightest local area 11th and 12th graders could correctly answer.
If a car traveling a distance of two miles has an average velocity of 30 mph in the first mile, how fast must it go in the second mile in order to achieve a 60 mph average velocity for the entire distance?
Everyone here is welcome to take a stab at it, and to comment on and/or challenge others’ responses. I’ll report the answer later in the day
VT etal- Vya con Dios.
G
Infinitely fast. Gawd that was easy. Are they really that dumb?
Kansas School system making little Republicans of the future.
Sky Angel Cowboy
http://www.youtube.com/watch?v=C0r_FbARIn8&NR=1
I would think that the car would have to go 90mph in the second mile to achieve an average of 60 for the two miles.
But, there is not enough information to answer the question. How fast can the car accelerate from 30 after the first mile is completed? A car clearly cannot go from 30 to 90 instantaneously, and rate of acceleration will play a factor in total average speed.
120 = (30 + X) / 2
X= 90
” would think that the car would have to go 90mph in the second mile to achieve an average of 60 for the two miles.” — Craptor
Yep! They really are.
I solved the problem by the time I was done reading it. It’s not a speed problem, it’s a time problem.
To average 60mph for two miles you have to do it in two minutes, To average 30 miles an hour in one mile you have to do it in two minutes.
There is no time left to ‘average’ 60mph for two miles if you are out of time at the one mile point.
Blue Jay, you’ve just proven mathematically you aren’t that bright.
Haw, Haw, Haw. Goobers. How many kids did you guys name Eurea?
9,030 mph :D
Blame it on the stroke…
O.K., I’m a kind man. I suppose I could watch goober after goober flounder. But I’ll give you a hint. No I won’t. It’s too fun.
Note all the drooling goobers thus far have been cons.
Of course if I’m wrong, I’ll have to come back under another name.
Like Eurea Bucket
Sorry B.J., the majority of the goobers have been cons. Haw, haw, haw.
Infinitely fast. 60 mph = 1 mile/minute. 2 miles – 2 minutes.
30 mph – 0.5 mile/minute. 1 mile – 2 minutes.
So, after 1 mile he has used up his 2 minutes and must instantaneously reach his 2 mile point to average 60 mph.
And this is before coffee cup #2.
O.K. Fun’s over. But amazing that seniors in high school couldn’t answer it. HLP is right, as is BTH
This reminds me of one that sounds much more difficult but is still easy. Two locomotives are each travelling at 60 mph toward each other; starting from a position 120 miles apart. A fly that does 200 mph flies from one to the other; then reverses direction again and again until the trains collide. Assuming the fly has instantaneous accelleration; how far does the fly travel before he gets squished?
Actually, it’s not infinite acceleration either as the answer requested an averaged speed. :)
Wow, I’m impressed Hank and BTH…I was never good at this sort of thing, I always hated math and physics…I’m much too right brained.
FYIII,
The answer is infinitely fast. This is because going 30m/h uses all the time necessary it would take for the car to go the 2 miles at an avg. 60 m/h. As it would need to cover the last mile in 0 seconds.
9030mph is the correct answer for an AVERAGE velocity for the second mile.
In non relative terms a non-specific entity is not requested in the problem to the initial time frame of 30 seconds from which the initial velocity is measured.
Therefore, the calculation requires that each portion (distance) be calculated separetly before averaging)
Since we are talking in no-relative expressions the velocity of A and the velocity of B must be calculated separately before they are considered in the additive portion fo the v=d/t time distance forumlae where velocities are non-relevant to to the specified moment in time.
The velocity of incident B, along with the time relevants of A and B are unknown, so they must be solved.
A is calculated
t1 = distance of A/velocity of A = 1 mile/30mph
B = distance of B/Averaged Velocity = 2 mile/60 mph
t1 = d1/v1 = 1mi/30.1mph = 1hr/30.1 = (10/301)hr (equation 1)
t = d/v = 2mi/60mph = 1hr/30 = (1/30)hr (equation 3)
tC = tA – tB = (1/30)hr-(10/300)hr = (300+1) – 300)/9030 hr = (1/9030)hr
v2 = 1mi/(1/9030)hr = 9030mph
resultant speed would be 1 mile at a rate of 9030mph because time A – time B equilibrates the non-linear function of the separate considered time references.
The formula for this is X * Y / 2X – Y
Where X is the first mile speed
and Y is the overall speed.
Ben: Here is my quick answer on your problem. The locomotives would meet up in one hour, when each has traveled 60 miles. The fly is traveling 200 mph and assuming instant acceleration and leaving at the same time as the locomotives, he would have covered 200 miles in that hour.
Hmmm, blog software chopped off half my answer and I ain’t re-doing it. :D
I don’t wish to take the good Mr. Huey on because I’d soon be very out classed. But he is wrong too! If you average any number with infinity the answer is infinity.
When your time is up, your time is up!
I use to teach post graduate level classes in nuclear physics. Doesn’t make me smart but it does make simple math, . . .well, simple.
“Change” you can believe in!!
“”WASHINGTON – An economic crisis, rising joblessness and a credit squeeze can make a president-elect refine his words. Today’s word is “repeal.” During his presidential campaign, Barack Obama promised to repeal President George W. Bush’s tax cuts for the wealthy ahead of their scheduled expiration in 2011.
It was part of how Obama would pay for an overall net tax cut aimed at low- and middle-income taxpayers, and an effort to bring what he called “fairness” to the tax system.
No one is talking tax hikes now.
Over the weekend, Obama said he has charged his new economic team with devising a plan that would create or preserve 2.5 million jobs over two years. He said the plan would include broad spending plans as well as the middle- and low-income tax cuts he described during the campaign.
Aides later said the plan would not include any of the tax increases Obama, as a candidate, had said he would impose on taxpayers who make more than $250,000.
Asked Monday when those hikes might go into effect, Obama said, “Whether that’s done through repeal, or whether that’s done because the Bush tax cuts are not renewed, is something that my economic team will be providing me a recommendation on.”
Obama’s economic advisers say he will not propose any tax increases in the economic plan he unveils in January. It is to be focused entirely on job creation and economic recovery.”
Apparently, we can;t afford the tax hikes? Or what?
Change. it’s what’s for dinner.
Change. it’s what’s for dinner.
==========
With a large portion of ‘Hope’ as a side.
outlander – correct. Again – deceptively simple.
Hank – disagree. Problem is – we are actually dealing in inverses in a sense so it just looks like it would be infinite in the end.
Hank – off topic – would like to kick around some nuke ideas sometime – maybe while chasing dogs. Has to do with water splitting and the question “just how hot is hot?” Can materials handle enough heat for entropy to trump enthalpy in a nuclear reactor? If so this could be the key to H2 as a fuel for vehicles. Like I tell my Sierra Club frinds – H2 cannot be an energy source but CAN be an energy medium.
Regular,
Your time is up.
Except, of course, Obama never said “repeal.”
The Shrub tax cuts got passed only with a black-letter sunset clause. The Republic Party promised it was a temporary attempt after 9/11.
The Republic Party tried in Congress to, ahem, repeal the sunset clause and make the tax cut for the wealthiest Americans permanent.
But no one has to do anything to end Shrub’s ever-so-successful-as-it-applies-to-the-economy tax cut for the rates to adjust back to pre-cut levels.
A 2% bump for the richest people on the planet.
Y’know… “socialism.”
The speed of 60mph trains and 200mph flies has little use in my life.
HLP gets this one.
The correct answer is, “It is impossible”.
Some students answered “90″, as did Raptor, which would be correct for a problem with equal TIME periods specified , e.g. “If a car travels for two MINUTES, and averages 30 mph for the first minute, how fast would it have to go in the second minute to achieve a 60 mph average velocity for the entire period.
As a quick contest-format answer 90 is reasonable, both because time is limited to figure out a solution, and because cars can go 90 miles per hour. Who would think of a car having a velocity of 300 mph, for example. 90 is, although incorrect, a realistic value.
“Infinite velocity” was the ostensible “correct” answer in the contest, but was, alas completely incorrect.
To see this, suppose there were such a thing as an infinite velocity. There isn’t–the speed of light is limiting– but what if there were.
Apply it when the car is at the mile-1 point, i.e. time = 2 minutes. The car must then be simultaneously at EVERY point in a trajectory. That is, it is not just at mile-2 instantaneously, it is at mile 1.0000001, 2.00000001, mile 10, 100, 1000… and 1,000,000,000,002,
and beyond. So it cannot be concluded that “infinite velocity” produces an average speed of 60 mph.
If xA = 1 mile (first mile) and xB = 1 mile, and t = 2 minutes, the problem shows
xA/t = 1 mile/ 2 minutes = 30 mph, AND we must also have (xA + xB)/2 minutes = 60 mph. These cannot simultaneously be true. “Infinite velocity” does not work, because to apply it would generate an infinitely large set of total-distance average velocities.
The underlying thing is that V = dx/dt where V is velocity, x is the distance, t is time, and d is the infinitesimal increment. Or for an average V = x / t
Here dt and t must be ZERO for the second mile’s passage, to get the putatively “correct” answer, but in actuality YOU CAN NEVER DIVIDE by zero. Mathematicians worked on this for a long time before coming to an agreement that division by zero must be relegated to a meaningless non-mathematicalproposition.
For example, 1 mile / 0 minutes does not equal infinity, because if 1/0 = infinity. then it must also be true that 1 = infinity x 0. But no matter how large a number is, if you multiply it by 0, the product is always 0, not 1 or any other real number.
Looked at another way, 1, 2, and 30 are unique real numbers. You cannot operationally combine them with a non-unique-real-number CONCEPT, i.e. infinity, to generate ANY unique real number, e.g. 60 in this case.
Fundamentally, velocity always requires time to elapse, in association with position specification. If we consider a problem in which dx/dt = v, dt can become infinitely small with 0 as a boundary limit, but never be 0 per se. dx, on the other hand can both have 0 as a limit and be 0 per se. (stationary object).
It is sad that someone, a teacher, testing some of Wichita’s brightest young minds, thought that he/she would give them a real brain teaser, but in fact possessed a serious mathematical misconception, which was then passed on to the contestants via their being informed of the “correct” (absurd) “answer”.
#
HLP
Posted November 25, 2008 at 9:28 am | Permalink
Regular,
Your time is up.
=========
No doubt,
But since an averaged time was given for the sum total, infinity cannot be considered as part of the calculation as it is an constant accelerating function that has no limits.
The problem clearly defines the limits as an average of 60 mph. :)
What is not apparent, is the regression of time over distance and constant variable rates of progressive constants through integration of time and rate.
This is the revolution conundrum. i.e., spinning a disc to make an attached object go at a certain speed requires the disc to spin at a faster rate than the resultant end velocity. Or, the other way around if one is directly relative to the distance over time.
(spin a wheel with a string and ball attached to it.)
The velocity of the string outside of the wheel is not infinite, but relative to the distance over time when incremental events are measured (time).
This is also known as the gear problem. That is, where engineers have to solve the speed how fast each successive gears need to move in order for the linear aspect of some force is realized (the clock chimes at a certain hour).
Math is not my concern today.
I am fasting in preparation for the great gorge in celebration of gobbler flesh, ‘colored’ potatoes, and pig rump.
(drooling)
Make square pies for Thanksgiving, it really pisses off the pie hogs. :)
Pie R NOT square — Pie R Round…
Pi R Square
Hank – disagree. Problem is – we are actually dealing in inverses in a sense so it just looks like it would be infinite in the end.
____________________________________________
I knew it! If I started down this path, sooner or later I’d have to actually think.
MPH equals miles divided by hours.
In the above problem you had two minutes and had to average 60 MPH. You used two minutes to travel the first mile, so you haven’t any time left to travel the second mile. Any number divided by zero equals infinity. Any number plus infinity equals infinity. Any number plus infinity divided by any other number (including infinity) equals innfinity. In short, your time is up.
___________________________________________
Can materials handle enough heat for entropy to trump enthalpy in a nuclear reactor?
___________________________________________
My first knee-jerk response would be to say, no. For a variety of reasons. To contain the fission process in a nuclear reactor that can produce any usuable power you’re biggest problem is not temperature, but pressure. Even then, it’s just one of many complex problems.
Enthalpy is a measure of a systems ability to do work. Intropy is more of an abstract term. (I always considered it kind of a fudge factor) Intropy is a measure of the energy in a system that is unavailable to do work.
In short, I kinda understand what you’re getting at but I’d have to give it a lot of thought to give you an answer.
Like I said – that is a discussion for while we chase the dogs around!
HEHEHE,
I don’t have to ‘chase’ my dogs! But we still need to get together some time.
No Chas,
The joke goes, “pie are round, cornbread R square.”
“If a car traveling a distance of two miles has an average velocity of 30 mph in the first mile, how fast must it go in the second mile in order to achieve a 60 mph average velocity for the entire distance?”
I don’t see time mentioned in the question. Probably, the questioner left out that “gotcha”.
The first mile is traveled at an average of 30 miles per hour. That takes 2 minutes for what it is worth. But it is not pertinent to the question, as asked.
In order to achieve an average velocity of 60 miles per hour over the 2 mile distance, the second mile must be traveled at 90 miles per hour. Just as Raptor and I said without over complicating the question.
I agree with BJ on this..where in the initial problem did it say anything about completing the course in 2 minutes?
So much for solving Global Warming. Obama to expand ROAD construction.
Just another Lie by Obama.
http://www.bloomberg.com/apps/news?pid=20601070&sid=a9u3×70pCs_4&refer=home
Obama to Boost Stimulus With Funds for Roads, Energy (Update1)
Raptor
Posted November 25, 2008 at 10:38 am | Permalink
I agree with BJ on this..where in the initial problem did it say anything about completing the course in 2 minutes?
2 miles at 60 mph = 2 minutes.
how fast must it go in the second mile in order to achieve a 60 mph average velocity for the entire distance
—————-
Time is a factor in velocity.
Eye halve a spelling chequer
I have a spelling checker.
It came with my pea sea.
It plane lee marks four my revue
Miss steaks aye can knot sea.
Eye ran this poem threw it,
Your sure reel glad two no.
Its vary polished in it’s weigh.
My checker tolled me sew.
A checker is a bless sing,
It freeze yew lodes of thyme.
It helps me right awl stiles two reed,
And aides me when I rime.
Each frays come posed up on my screen
eye trussed too bee a joule.
The checker pours o’er every word
To cheque sum spelling rule.
Bee fore a veiling checker’s Hour
spelling mite decline,
And if we’re lacks oar have a laps,
We wood bee maid too wine.
Butt now bee cause my spelling
Is checked with such grate flair,
Their are no fault’s with in my cite,
Of nun eye am a ware.
Now spelling does knot phase me,
It does knot bring a tier.
My pay purrs awl due glad den
With wrapped word’s fare as hear.
To rite with care is quite a feet
Of witch won should be proud,
And wee mussed dew the best wee can,
Sew flaw’s are knot aloud.
Sow ewe can sea why aye dew prays,
Such soft wear four pea seas,
And why eye brake in two averse
Buy righting too pleas.
I agree with ben.
The 2nd mile must be traveled at a speed that would stop time.
Crazy fast.
RP – I’ve seen versions of that poem – they are great!
Ben, as an educator, would you tell me why they always ask unrealistic or impractical questions on these types of test?
BlueJay and Raptor,
Time isn’t explicitly stated(you are correct there), however it is implied in the question. Thus one has to use the distance and velocity to determine times. I believe it stems from how one interprets this part of the question:
“achieve a 60 mph average velocity for the entire distance?”
In order to achieve that, one would have had to travel that distance in 2 minutes total time, but we already were traveling for 2 minutes in the first mile.
But lets argue the point a little further:
If the car could instantaneously accelerate to 90 mph for the last mile, that distance would be traveled in 40 seconds, the total time then is 2minutes 40 seconds(or 300s). Thus the actual average in this case: 44 mph. May want to check my numbers, but I believe those are accurate since I didn’t spend alot of time on the answer.
One could argue the infinite velocity(may have to get into quantum physics and I’ll admit a minor in physics isn’t going to explain it well enough), so I’ll go with the stated answer above as being impossible. It is easier that way.
To see if people are thinking. The thing is – if you pay attention the calculations are very simple.
Actually – I have never seen either of these on a test – just as riddles.
Now for another riddle – the Lady and the tiger:
You are locked in a room. There are two doors out – one leads to safety and the other to a certain and painful death. You don’t know which door is which. There are two guards. One ALWAYS tells the truth; one ALWAYS lies. You don’t know which guard is which. You are allowed ONE question you may ask one guard. What is the question?
Hint – you will get out alove but you will still not know which guard is the liar.
You are allowed ONE question you may ask one guard. What is the question?
——————–
Can I borrow your gun for a few minutes?
The speed of 60mph trains and 200mph flies has little use in my life.
I agree!
I always hated story problems in math. I now find I must use them daily. :( But at least in real life, I understand them.
P.S. I thought 90 mph for the car was the answer, too. Hey, I never said I was good at math.
“What is the question?”
Which door will the other guard say is the save door?
Then go out the other door.
Won’t work. The liar will say YES and the truth-teller NO but you won’t have the gun. Still stuck.
Ask either guard which door the OTHER guard would say leads to certain and painful death.
Then choose the other door.
Guard who always lies will tell you the wrong door because he knows the truthful guard will tell you the right door.
Guard who always tells the truth will tell you what the liar will say…which is the wrong door.
In either case, if you choose the door other than what’s given in the answer then you win…without firing a shot!
(this is a version of another Marilyn Vos Savant puzzle, fyi)
“Pedant
Posted November 25, 2008 at 11:41 am | Permalink
Ask either guard which door the OTHER guard would say leads to certain and painful death.
Then choose the other door….”
That is like when my wife asks how an outfit looks, I tell her it is lovely and she puts on something else
This might just be appropriate to the thread:
http://abcnews.go.com/US/wireStory?id=6329327
Ask a guard which is the door to the tiger(doesn’t matter which guard). Then pick the other door.
If there are only 2 doors and I have a choice of going through either of them, why are there guards in the room?
Pedant – et.a’. – bingo! the answer will be a lie regardless of which guard you ask.
Ben, please explain??
“djr4488
Posted November 25, 2008 at 11:49 am | Permalink
Ask a guard which is the door to the tiger(doesn’t matter which guard). Then pick the other door.”
Doesn’t work. The key is Pedant’s COMBINING the guards.
A quantum car would be at both ends of the road at the same time. But which one forgot the groceries?
Chas – the ‘composite’ question will result in a lie as the answer. “If I ask him which door leads to safety what will he tell me?”
If I ask that of the liar he will know that the truth-teller would give me the right door. But, being a liar he will say the opposite – trying to send me to the wrong door.
If I ask the truth-teller he will know that the liar would send me to the wrong door. So, telling the truth, he will give me the lie the liar would have given me.
Either way I get a lie. But, by reversing it I get out. And still don’t know which guard is which.
Ahhh — ok… got it now…
Jed – I have seen that in science too. The frustrating thing then is that they don’t find science to be fun and that rubs off on the students in a very bad way.
Anybody know how Road Construction is bad for Global Warming??
Not to belabor the point too much, but the analysis on the car question inaccurately assumes a 2 minute time to complete the 2 miles. Nowhere does the initial problem say it has to be completed in 2 minutes.
Saying with an average speed of 60, the two miles would be covered in 2 minutes is circular logic and inapplicable. It would be accurate to say with a CONSTANT speed, the distance would be covered in 2 minutes. The question asks average speed, not the time it took to cover the course, which are two different things.
If a car goes 1 mile at 10 mph and 1 mile at 20 mph, the average speed for the distance is 15…regardless of the time it takes to cover the distance.
Removal of land from carbon sequestration. Encouraging single-occupant vehicle use.
Actually, I favor some road construction – especially de-bottlenecking. But I would also like to see alternative transportation.
“Raptor
Posted November 25, 2008 at 12:37 pm | Permalink
….Saying with an average speed of 60, the two miles would be covered in 2 minutes is circular logic and inapplicable. It would be accurate to say with a CONSTANT speed, the distance would be covered in 2 minutes. The question asks average speed, not the time it took to cover the course, which are two different things.
If a car goes 1 mile at 10 mph and 1 mile at 20 mph, the average speed for the distance is 15…regardless of the time it takes to cover the distance.”
So Raptor, if you drive to KC and some one asks what your average speed was how do you calculate it? You divide the trip distance by the time it you to get there, right? If your drive was 120 miles and it took 2 hours, your average speed was 60mph.
If that doesn’t turn the lighbulb on I cannot help further.
#
Chas
Posted November 25, 2008 at 12:28 pm | Permalink
Anybody know how Road Construction is bad for Global Warming??
________________________________________________
What do you mean by. “. . . is bad for Global Warming??”?
“Chas
Posted November 25, 2008 at 12:28 pm | Permalink
Anybody know how Road Construction is bad for Global Warming??”
I do not think any particular road construction project would have a measureable or identifiable impact on the average temperature of the planet.
Ya Raptor it’s a poorly phrased question. I see both sides.
However, an infinite speed is an impossibility when a finite speed (over a distance is given as answer. 60 mph average velocity for the entire distance?)
The question was porked from the beginning. :)
“If a car goes 1 mile at 10 mph and 1 mile at 20 mph, the average speed for the distance is 15…regardless of the time it takes to cover the distance.””
I agree brian – his conclusion is wrong. BUT – if units of time then it DOES work:
1 hour at 10 mph and 1 hour at 20 mph. 2 hours; 30 miles. Ave speed – 30/2 = 15 mph.
BUT: 20 miles at 10 mph = 2 hours. 20 miles at 20 mph = 1 hour. Total distance 40 miles in 3 hours. Ave speed 40/3 = 13.333 mph.
What do you mean by. “. . . is bad for Global Warming??”?
HANK — I have no clue… See JimJohnson upthread… he was griping about it…
Chas
Posted November 25, 2008 at 12:28 pm | Permalink
Anybody know how Road Construction is bad for Global Warming??
——————
The horses that will travel on the roads are ‘bad for GW’, sweet Chas.
If a car goes 1 mile at 10 mph and 1 mile at 20 mph, the average speed for the distance is 15…regardless of the time it takes to cover the distance.
_____________________________________________
1 mile at 10 MPH would take 6 minutes. 1 mile at 20 MPH would take 3 minutes for a total of 9 minutes to go the 2 miles.
If you go 2 miles at 15 MPH it would take you 8 minutes.
Try again. scooter.
Who’s on first?
I’m confused.
Damned Thorazine, anyway…….
Be kind to the poor dyslexic liberal…
If a car goes 1 mile at 10 HPM and 1 mile at 20 HPM the average speed for the distance is 15 (HPM)…regardless of the time it takes to cover the distance.
Let me try and clear this up for scooter and BlueJay:
If you can mow lawns at an average of one lawn an hour and it takes you two hours to mow the first lawn, how fast must you mow the second lawn to maintain your average of one lawn an hour?
PS. Your lawn mower’s speed is limited by the speed of light.
PPS. This is not a ‘union’ landscaping service.
PPPS. Assume your mower is already running and your break is over.
“Fleetwood named new chief judge for Sedgwick County district court”
And what an honor it is!
You are going at it from an established point…you already have an average. If, however, I do one lawn in 1 hour and another in 1 hours, that makes an average of 1.5 hours to do a lawn, regardless of how fast I am moving!
Besides, you left something out. Are the lawns the exact same size? Is the grass the same length/density? Are there the same number of obstacles (trees, bushes, small children, abandoned cars) in both yards?
Raptor,
I think the issue is, you are forgetting the time portion of velocity. Also the equation that needs to be considered is: distance = velocity * time. Time while not directly stated is an important factor non the less.
Since we know both distance traveled and velocity, time can be determined. So time is critical in the solution of the problem. The question asked what would it take to achieve an average of 60 mph over the entire distance of two miles.
So we have three equations:
d1 = 1 mile
v1 = 30 mph
t1 = ?
Thus the first equation is:
1mi = 30mph * t1
t1 = 1/30 hours, or 2 minutes
What we need is:
d2 = 2 miles
v2 = 60 mph
t2 = 2 minutes
The second equation becomes:
2mi = 60mph * 1/30
Which means to travel 2 miles at an average of 60 mph, we need 2 minutes. But we’ve already traveled for two minutes, which is how we can conclude that we’d have to travel instantaneously 1 mile to meet our average speed we want(infinite speed or impossible).
The third equation shows how fast we cover 1 mile at 90mph:
d3 = 1 mile
v3 = 90 mph
t3 = ?
Assuming the car instantaneously accelerates to 90mph(should we calculate the g-forces for the fun of it? I think not.), then we get:
1mi = 90 mph * t3
t3 = 1/90 hours, or 40 seconds.
Thus we have a total time traveled of 2 minutes 40 seconds.
If we know that, we can figure out our average velocity for the entire trip was:
d4 = 2miles
v4 = ?
t4 = ~.044h, or 2 minutes 40 seconds
2 mi = v4 * .044h
v4 = 2mi / .044h
v4 = ~45.5
I had a typo in my first response. I hope this clears it up.
Is the math test still next Monday?
Damn, we better keep cramming or we will never pass
” If, however, I do one lawn in 1 hour and another in 1 hours, that makes an average of 1.5 hours to do a lawn, regardless of how fast I am moving!”
There has got to be a typo in there somewhere…
actually, the thought of requiring some sort of test before a login is issued probably has some merit
Besides, you left something out. Are the lawns the exact same size? Is the grass the same length/density? Are there the same number of obstacles (trees, bushes, small children, abandoned cars) in both yards?
_____________________________________
The grass in the second lawn is not high enough to hide a tiger.
Hank — sort of hard to figure out a problem without some sort of parameters…
yes…was a typo, chas. Math never was one of my strongest subjects–obviously!
Anybody know how to cook toilet paper?
I think you just brown it, then toss it in the pot.
The more they write, the more they confuse themselves. :D
Actually, the time was given as a rate (miles per hour). 60mph on the second leg of the trip (average speed)
As I said, it is a bad question, over complicated by subjectivity. :)
Regular posted November 25, 2008 at 12:49 pm
Ya Raptor it’s a poorly phrased question. I see both sides.
However, an infinite speed is an impossibility when a finite speed (over a distance is given as answer. 60 mph average velocity for the entire distance?)
The question was porked from the beginning. :)
———————
“in order to achieve a 60 mph average velocity for the entire distance?” was a requirement, not an “answer”.
And it’s a good, and simple problem, if you look at the d/t parts logically.
If you don’t look at those logically, it helps teach you how to do so.
Some problems don’t have solutions, and some have odd ones, like infinite velocity.
Just for you, cosmos!
http://www.iht.com/articles/2008/11/25/europe/25klaus.php
An economist. . .
http://en.wikipedia.org/wiki/Vaclav_Klaus
Soon to be president of the EU!
computer broke for 2 days and cosmos I prefer beer with my cheese……….and whats your face (mkxp?????) you are said human being
GOOOOO KLAUS!!!
Klaus has had some scandal problems….
Cosmos will soon tell us Klaus in not a peer reviewed scientist…
Cosmos, what’s on the Eco-Nazi menu for Thanksgiving this year?
Just curious.
Klaus is a vocal critic of the notion that any global warming is man-made (anthropogenic): “Global warming is a false myth and every serious person and scientist says so.”[25] He has also criticized the Intergovernmental Panel on Climate Change as a group of politicized scientists with one-sided opinions and one-sided assignments. He has said that other top-level politicians do not expose their doubts about global warming because “a whip of political correctness strangles their voices.”[26]
In addition he says “Environmentalism should belong in the social sciences” along with other “isms” such as communism, feminism, and liberalism. Klaus said that “environmentalism is a religion” and, in an answer to the questions of the U.S. Congressmen, a “modern counterpart of communism” that seeks to change peoples’ habits and economic systems.[25]
-wiki
I like Klaus’s views on this, others not so much.
ANTI = two bit hoodlum/right wing alarmist
correction: two bit cyber-hoodlum
Notice cosmos offers no solution, but is critical of others that attempt to offer a solution.
Perhaps there was no Web page for cosmos to link to for an answer.
(chortles)
Chas
Posted November 25, 2008 at 3:57 pm | Permalink
ANTI = two bit hoodlum/right wing alarmist
==============
Please explain your outrage, dear Chas.
no outrage — just facts
Chas
Posted November 25, 2008 at 4:01 pm | Permalink
no outrage — just facts
———–
I am listening.
Still listening……(@ @)
Struggling Banks Paid President Clinton $2.1 million for ‘Speeches’
http://www.cnsnews.com/public/content/article.aspx?RsrcID=39902
RP_McMurphy is CooCoo.
How many million years old do environmentalists estimate the planet to be?
about 4000-5000 million years or so.
So we have a planet that is 4 million years old. We’ve measure weather for the last 100 or so.
Measuring .000025 of history and the climate changes are the fault of industry (man) and not a natural cycle?
We have much better data that that kia. It’s called geology and paleoclimatology.
How does a rock indicate temperature at certain year within a tenth of a degree?
“RP_McMurphy is CooCoo.”
Liberating to us sane people?
Another quiz. This time, though, it’s neither math nor logic but American civics and some economics, with a skootch of Western Civ thrown in for good measure.
Very, VERY basic Western Civ at that (and I’m ashamed to admit that I got only 32/33 on this one, missing the very last one…although the national average is less than 50% and American college educators averaged a mere 55%! ).
http://www.americancivicliteracy.org/resources/quiz.aspx
If you’re flummoxed by decimal points, differential calculus, or logic puzzles, check it out.
As shown by the Kansas Department of Health and Environment (KDH&E) final report of abortion statistics for 2007, abortions in Kansas dropped by 3.8%, and post-viable infanticides dropped by 23%. This is mainly because of pro-lifers engaging in prayer, monitoring, and demonstrating against Tiller’s criminal late-term Wichita abortion mill, thereby forcing the mill to shut down for 38 days in July and August of 2007.
- – -
Leslie Owen Collier of Charleston, MO has been in prison since 1996 for illegally killing 3 bald eagles with pesticide intended for coyotes, and has finally been pardoned by President Bush.
You can be sure that rabidly pro-abortion Obamanation will be pardoning any abortionist quacks like Tiller convicted of illegally killing babies, and applauded by the media for doing so. Looks like courtroom stalling tactics by Tiller and Planned Parenthood abortionist quacks will pay off, even if they get a just sentence.
[A just sentence would be highly unlikely, as our criminal justice system is not allowed to employ millstones in sentencing.]
The media cares about protecting eagles, not babies.
- – -
A lot of so-called “people of conscience” are endorsing Obamanation’s plan to strike down all state laws restriction abortions. Why isn’t the pro-abortion media even asking any sensible questions, like “will medical cleanliness and safety regulations be struck down?” and “can informed consent still be enforced?”
[Kansas has NEVER enforced cleanliness and safety regulations or informed consent in abortion mills, by the way. These bills were vetoed by Bilious Sebelius and override stopped by so-called legislators bought up for the pockets of abortionist quacks.]
ANTI – never said it did within a tenth of a degree.
Take a few paleoclimatology and sedimentology courses – they are fun and you might learn something.
You can be sure that rabidly pro-abortion Obamanation will be pardoning any abortionist quacks like Tiller convicted of illegally killing babies, and applauded by the media for doing so.
Care to make a wager on that parkay?
“You answered 33 out of 33 correctly — 100.00 %”
Take a few paleoclimatology and sedimentology courses – they are fun and you might learn something.
============
If I had the time I would. In fact, I would go to school full time if I didn’t have to worry about money! ;)
(raises pant legs for all the “scientific” bull shyt.)
Regular
Posted November 25, 2008 at 5:09 pm | Permalink
(raises pant legs for all the “scientific” bull shyt.)
=============
I bet your one of them ‘deniers’, ain’tcha?
Somebody get a rope!!!
;)
your=you are….
http://www.americancivicliteracy.org/resources/quiz.aspx
You answered 30 out of 33 correctly — 90.91 %
Average score for this quiz during November: 78.1%
Average score: 78.1%
“Guilty On All Counts”—-from American Values
“That was the verdict on 108 charges, after years of investigations and two trials, for five top officials of the Holy Land Foundation, a Muslim charity accused of funneling nearly $60 million to the terrorist group Hamas. This was a major victory for the Bush Administration, which, of course, is why you probably didn’t hear about it. Patrick Rowan, the assistant attorney general for national security, said, “Today’s verdicts are important milestones in America’s efforts against financiers of terrorism. This prosecution demonstrates our resolve to ensure that humanitarian relief efforts are not used as a mechanism to disguise and enable support for terrorist groups.” Ostensibly created to help needy Palestinians, the sweeping convictions prove the difficulty of identifying and working with so-called “moderate” Muslim groups.
Other news today highlighted the evil nature of the Islamofascist enemy we are fighting in Afghanistan. The Associated Press reports that 10 Taliban thugs have been arrested for “acid attacks” against 15 Afghan girls and teachers who were walking to school. Under the Taliban, girls were banned from going to school, and today they still risk being sprayed with acid for daring to get an education. Only the most delusional optimists would fail to see that an enemy this vicious cannot be negotiated with, but must be defeated by men and women who possess the moral clarity and courage to fight evil when they see it. Pray that our nation will maintain such moral clarity in the years ahead.”
ANTI
Posted November 25, 2008 at 5:11 pm | Permalink
Regular
Posted November 25, 2008 at 5:09 pm | Permalink
(raises pant legs for all the “scientific” bull shyt.)
=============
I bet your one of them ‘deniers’, ain’tcha?
Somebody get a rope!!!
—————–
sure,
I live by ‘de nile’ river…
sure,
I live by ‘de nile’ river…
———
We must be neighbors. Howdy
Nature, on the loose!
http://www.bloggingwv.com/you-know-your-a-badass-spider-when/
More…
http://www.tonyrogers.com/humor/bearfeeder.htm
ANTI,
Klaus’ education, occupation, and especially his own statements proves that he is not a credible climate scientist.
“ANTI
Posted November 25, 2008 at 5:07 pm | Permalink
…
If I had the time I would. In fact, I would go to school full time if I didn’t have to worry about money! ;)”
or passing classes, lol
:)
The FL Supreme Court struck down the FL law that prohibited Gay couples from adopting children… calling the law Unconstitutional…. Finally some sense of sanity is returning….
#
cosmos_originally
Posted November 25, 2008 at 6:27 pm | Permalink
ANTI,
Klaus’ education, occupation, and especially his own statements proves that he is not a credible climate scientist.
————————
So what is your education, occupation and back ground that qualifies you to be the judge of other people whether or not they are qualified to speak on climate?
Hmmm?
Come on cosmos… you love to blast other people saying they are not qualified…
How are you qualified?
or passing classes, lol
===================
You are right Brian, it’s because I never learned to read.
Thanks for making me feel horrible!
(tear)
Regular,
List your proof that the economist Klaus is a qualified, credible climate scientist.
So what does citi’s ceo mean by this statement? That they were investing in CDS and/or derivatives?
What went wrong is we had tremendous concentration in the sense we put a lot of our money to work against U.S. real estate,”
At least he wasn’t blaming freddie and fannie.
Like many on the blog have.
List your proof that the economist Klaus is a qualified, credible climate scientist.
========
Cosmos,
I don’t think anyone said Klaus was a qualified, credible climate scientist.
Regular,
Refute this.
http://www.sciencemag.org/cgi/content/full/306/5702/1686
http://logicalscience.com/consensus/consensus.htm
Cosmos,
Refute this:
http://xzdarkstarzx.com/img102.jpg
We must stop these things!
ANTI,
Refute all of the science in these reports. Or at least try to read them.
http://www.ipcc.ch/ipccreports/ar4-wg1.htm
cosmos_originally
Posted November 25, 2008 at 9:38 pm | Permalink
Regular,
Refute this.
——————-
cosmos,
They have certification boards, registrations, boards and other methods to make sure people are qualified to approach a subject in a qualified manner.
In climate, there can be anything from a bug hunter to a nuclear physicists looking at climate.
Where do you get off judging the qualifications of others? You are one person and no one appointed you King.
It’s becoming quite apparent you have zero qualifications in anything and are just plain scared to admit so.
Cosmos, see my earlier post.
I never learned to read!
Cosmos,
Besides, your science is my political nob job.
knob
Regular,
Thank you for admitting that you cannot prove that the economist Klaus is a qualified, credible climate scientist.
And thank you for admitting that you cannot refute the very strong scientific consensus re AGW.
Regular, please continue your wild arm flailing, and stupid, irrelevant ad hominems.
Or don’t. . . if you’re still too weakened from your recent Election day stroke.
good night; good luck; god bless —-
whatever you conceive god to be!!
blessings ALL!!
happy thanksgiving!!
so mote it be!!