1...2....

2 pages

ah..ah..ah...ahhhhh

4/30/2009 2:05:03 PM

4/30/2009 2:05:40 PM

but will the plane take off?

[Edited on April 30, 2009 at 2:08 PM. Reason : .]

4/30/2009 2:08:25 PM

only if the answer is -8 m/s

4/30/2009 2:09:38 PM

not only will the plane take off, but to the left and between 0 and 4 seconds of some time interval, the average velocity will be 8 meters-per-second

so then it will crash because its not going fast enough

[Edited on April 30, 2009 at 2:10 PM. Reason : LEFT A WORD OUT]

4/30/2009 2:09:52 PM

Quote :

"I integrated the equation to get "2(t^2)-(t^3)" and divided by b-a (4-0=4). [2(4^2)-(4^3)]/[4-0] = (32-64)/4 = -8 m/s "

is what i did...

[Edited on April 30, 2009 at 2:53 PM. Reason : ^winnar]

4/30/2009 2:53:24 PM

Quote :

"haha, he probably wrote down the wrong damn question"

I swear I didn't. There was only 2 questions that stumped me out of the 30 on the exam. I was literally scratching my head because I knew I couldn't be overthinking it or anything. I mean fuck, I was calculating crazy shit like how fast a 3 kg block would move if shot by a 3 gram bullet and other hard problems and getting the answers real easy. Then there were two (one dealing with sound waves that I admit I didn't study much on), and this one which just seemed retarded that the answer was NOT THERE. >_< I thought about leaving it blank because the correct answer was not present, but then I figured -11 m/s might just be it somehow...

[/blog]


btw, the plane is a submarine. GG

[Edited on April 30, 2009 at 2:56 PM. Reason : .]

4/30/2009 2:54:52 PM

i got -8 m/s, am i an idiot

[Edited on April 30, 2009 at 2:59 PM. Reason : /]

4/30/2009 2:58:52 PM

Quote :

"The average velocity is NOT the average of the final and initial velocities. That is asinine."

it is when velocity is a linear function of time

[Edited on April 30, 2009 at 3:00 PM. Reason : t]

4/30/2009 2:59:47 PM

average velocity is the distance traveled divided by the time, you don't need calculus to solve this

4/30/2009 3:03:02 PM

leave it to wolfwebbers to adamantly insistent that an incorrect approach is right, and that a correct approach is wrong, because they fail at reading.

Though to be fair, it's probably just the chit-chat factor. Posting this thread in Study Hall means it would never make it to two pages, but it would probably have a higher proportion of correct answers.

[Edited on April 30, 2009 at 3:26 PM. Reason : ]

4/30/2009 3:21:47 PM

Quote :

"average velocity is the distance traveled divided by the time, you don't need calculus to solve this"

yep

Quote :

"it is when velocity is a linear function of time"

yep

Quote :

"eave it to wolfwebbers to adamantly insistent that an incorrect approach is right, and that a correct approach is wrong, because they fail at reading. "

but trolling is such fun!

though i do think the answers (choices) are not right, the one's we have collectively found are...

-8m/s

4/30/2009 3:44:42 PM

plane.....treadmill.....flight....no

4/30/2009 5:37:16 PM

Quote :

"Your professor is wrong. The plane takes off. Third grade is now super complicated. No, we're not playing fucking stonehenge. I changed lanes without signaling while running a red light and speeding. THE ANSWER IS NEGATIVE FUCKING EIGHT. "

FTW

4/30/2009 6:08:26 PM

is velocity directional?

because x is obviously directional

but should velocity be considered positive or negative?

4/30/2009 6:53:42 PM

velocity is a vector

speed is a scalar

4/30/2009 6:56:54 PM

it just means it's going in the negative direction right

4/30/2009 6:57:08 PM

yes

4/30/2009 6:57:25 PM

I just found out teh velocity at diff times i.e V@0,1,2,3,4 secs and took the avg. there are simpler ways of doing it.. but u'll still get -8m/s

4/30/2009 7:00:17 PM

wow to the first page

4/30/2009 7:16:16 PM

its -8, it would be -11 if it where from 1 to 4 though, did it say the velocity at t=0?

4/30/2009 7:24:41 PM

this has been bothering me all day, someone confirm -8 m/s so i can stop feelin like an idiot

4/30/2009 7:25:27 PM

It's possible for the final to be wrong. On my physics final, I think 2 problems had bad answers, and the questions had to be thrown out. This wasn't determined until after the test was over though.

4/30/2009 7:30:24 PM

Looks like -8 m/s to me, but I'm not an applied physicist either.

ibt42

4/30/2009 7:45:49 PM

You can do it from the position function (change in distance over change in time) and you do it by differentiating it.

Either way, the answer is -8 m/s.

4/30/2009 7:58:45 PM

I also calculated -8

What is your professor's name? We should all email him.

4/30/2009 8:01:31 PM

Yes it did say starting from t = 0. Interesting that it works at t =1 . I wonder if it's a typo, either way, I've emailed him this morning. No response yet.

4/30/2009 9:59:31 PM

at t(0) you are at 0 m
at t(1) you are at 1 m
at t(2) you are at -4 m
at t(3) you are at -25 m
at t(4) you are at -32 m

so I don't think you can just do -32/4 = -8 because you actually went further than 32 m?

[Edited on April 30, 2009 at 10:18 PM. Reason : missed a -]

4/30/2009 10:13:29 PM

huh? how did you go further than 32 m?

you went from 0 m to -32 m in 4 seconds.

average velocity is -32/4 m/s.

4/30/2009 10:15:53 PM

^^you determine average velocity by net displacement

[Edited on April 30, 2009 at 10:17 PM. Reason : .]

4/30/2009 10:17:10 PM

^^ you went from 0 to (at least) 1 before going negative

its like if i drove 1 mile N and then 33 meters S I went from 0 to -32 but i drove more than 32 meters

4/30/2009 10:21:48 PM

all that matters is the NET displacement

[Edited on April 30, 2009 at 10:22 PM. Reason : final minus initial motherfucker]

[Edited on April 30, 2009 at 10:23 PM. Reason : vector vs. scalar]

4/30/2009 10:22:34 PM

VELOCITY

not

SPEED

4/30/2009 10:25:08 PM

the answer is faraday

4/30/2009 10:27:53 PM

Quote :

"VELOCITY not SPEED"

doh

4/30/2009 10:36:35 PM

answer is DP/DT

4/30/2009 10:39:18 PM

Quote :

"Your analysis is correct. Evidently those "5"s were mistyped and should have been "8"s."

ha

5/2/2009 4:48:55 PM

yea drod just got avg position, which doesnt tell you anything

5/2/2009 5:55:55 PM

Oops, forgot to say that ^^ was what the prof. emailed back.

5/2/2009 5:57:39 PM