:thumbsup

actually it got negative decellaration
so it should go backwards

not in this context, because after a full brake, the train wont go backwards, it will just stop moving

30 times farther then it was 30 seconds ago

I found interesting in BDJUF.

BDJUF, you just got yourself rekon by your greatness.

:thumbsup

Mr. Wong. You're full of knowledge too!!! :thumbsup

Didn't even see this. This is also correct. The train will travel -900m. How long would the train travel total? 1200 miles.

What's 1200-900=300 meters.


bdjuf where do you even address the time 30 seconds in your equation?

i'm coming up with 900 meters and here's why, instead of using vector analysis i used D= 1/2*(A*T^2)
D is the distance you're looking for, a is the absolute value of your acceleration and T is the time (30 seconds)

it's the same formula you use to calculate how fast something will fall with gravity except you replace the A with the gravitational constant.

that makes any sense or am i just high?

wow i was so fucking late on that. :Graucho

omg, i knew this stuff at 9th or 10th grade or something..

how many of you are high school dropouts?

the graph shows that it would stop after 20 seconds, because of the deceleration speed

the extra 10 seconds would be 10 seconds of rest, in this case

if there WAS no context, then yes, it woulda been 300m because he woulda went 100m backwards

but since there IS context, its 400m :thumbsup

Yes, that's right. BUT it reads 0 + 1200 - 900 = 300meters. Luc, just fucking write down 300 meters. It's fucking right.

wanna bet? :thumbsup

I don't ever recall doing these kinds of problems in high school.
What kind of math is this, Calculus???

physics class in highschool and college :thumbsup

Prove it with an equation. You have mine and it checks. You have 2 others that also check. Your graph doesn't even match up to what you're saying. You have X as the unknown which you are using as time, but your also using the slope as time? You can't use both sides as time!

that is a formula for the answer in Newton/second, you cant apply that in this context, unless you want to find the force of the train or something :thumbsup

there is no equation because it is not a theoretical question! its a PRACTICAL question, of a specific situation!
that is why we use graphs!

please tell me the flaws on my graphs for me to believe you :thumbsup

BDjuf has grahp supports ....... I don't think he's wrong.

still waiting!!!

thats exactly it, in their equation, it includes the train going BACKWARDS!!!!

want proof? replace the 30 seconds with 500 seconds, they would come up with a negative number :thumbsup

So basically to summarize it all you're saying you disagree with all of Einstein's theories and in particular you dispute his papers on relativity?

:1orglaugh this has nothing to do with einstein and relativity! its the way you proceed to solve these problems!!! :1orglaugh

:1orglaugh Technically it may have something to do with einstein's theory of relativity - it all depends on the location & velocity of the time keeper relative to the direction of the train's travel.
I guess to have the question layed out better, the time keeper should be positioned in the train to ensure we can rule out einstein's relativity theory interfering with the answer

alright, Im hoping to make this my last post on this thread with a more comprehensible (I hope) graph that I just made

http://www.wantsmut.com/luc2.jpg

I hope this helps you understand better :thumbsup

by the graph we see that
after 20 sec, the train will stop, and it doesnt matter if you add an extra 10, the distance wont change.

v0=40m/s
a=-2m/s^2
t=20s
----------
v=?
x=?
----------
v=v0-at (- because the acceleration is negetive)
v=40-2*20
v=40-40
v=0 - the speed after 20 sec
--------------------------------------
x=x0+v0t-at^2/2
x=40*20-2*20^2/2
x=800-400
x=400
-------------------------------------
the train will travelled 400meter within 20 secs, thats why the train travelled the same distance with 30 sec..
hope i helped.

well done! and thanx for proving my point :thumbsup

hey dumb ass, 2m/s/s is an acceleration not a speed. :1orglaugh

yeah? and Ive been treating it as a acceleration this whole time?
whats your point?

guys!
bdjuf is fucking right!
the train will stop after 20 SEC, here is the proof:

v=v0-at (- because the acceleration is negetive)
ok!
we need to know when the speed will be 0, so we will see how much time it takes!

so:
v0=40m/s
a=-2m/s^2
v=0
-----
t=?
----
0=v0-at
0=40-2t
-40=-2t
t=20sec
the train will stop after 20 sec, thats it! no more argue!

380 - thank you for playing

What's the deal, your dungeons and dragons groups not show up tonight?

I don't think they had physics at my high school, I think it was must have been an Honors class or something like that. I remember Chemistry and Biology though... :(

I HATE math/chemistry equations crap. This shit gives me a fucken headache just looking at the equations :helpme

they had general physics in my highschool in the 9th grade.

but we were all too busy putting spit wads up our noses and flicking them onto Theresa mantzke's lips.

:helpme

Could we have someone write a php script to demonstrate? People here seem to love writing php scripts

I dont think there is anything left to demonstrate :1orglaugh
I gave the graphical approach
and freesex gave the theoretical approach

this thread should be closed

FINAL ANSWER: 400 meters

Ok then just for completion.. how about you go over any assumptions made in coming up with your answer?

I wasn't talking to you. I was referring to the original thread. I have degrees in engineering and physics and this is a high school problem :1orglaugh :1orglaugh

Your analysis, while the long and drawn out, is the correct answer.

good to hear that, and thanx for the feedback :thumbsup