Math Problem!!!!

[Luc Duboi]

A train is running at the speed 40 m/s , suddenly the driver pushes the brake and it reduces to -2 m/s^2 .

Question : After 30 seconds, how far can that train go ?

[buddyjuf]

400meters because it would have stopped @ 20 seconds

[RedShoe]

about 100 miles. yeah, yeah definitely about 100 miles.

[Luc Duboi]

scientific answer please. no guessing!!!

400 how ?

100 how ???

[SpaceAce]

I made this image a long time ago for another one of Luc's threads but I didn't get around to posting it. This is probably as close as I will ever get to having another chance, so here it is

<IMG SRC="http://friends.porncherry.com/images/original/aznmath.gif">

SpaceAce

[buddyjuf]

40 m/sec, slowing down @ 2m/sec makes it 20 secs before it reaches zero.

the graph forms a rectangle triangle with 1 side measuring 40, and the other measuring 20, to find the surface of the triangle, wich represents the distance in meters, you do (40 X 20)/2 wich gives you 400 meters.

didnt you learn anything in physics class?

[Saintgames]

damm metrics... how many MPH is that??

[Luc Duboi]

Originally posted by SpaceAce
I made this image a long time ago for another one of Luc's threads but I didn't get around to posting it. This is probably as close as I will ever get to having another chance, so here it is

SpaceAce

you're very tricky!!!

[Overscore]

d=.5(a×t^2)
d=.5(-2m/s^2×30s^2)

The train will travel -900m.

[Luc Duboi]

Originally posted by Saintgames
damm metrics... how many MPH is that??

m/s = meter per second.

[buddyjuf]

Originally posted by Luc Duboi


m/s = mile per second.

fuck no
m/s = meters per second

what kind of thing could go @ 40MILES a second?!?!?!

[CDSmith]

The liquor store is 12 km from my house, and it closes at 11 pm. If I drive at 70 km/h all the way there, buy a 66'er of vodka on sale for $38.95, then drive at 60km/h all the way back, can I feasibly be drunk by midnight?


No using a calculator!

[buddyjuf]

Originally posted by CDSmith
The liquor store is 12 km from my house, and it closes at 11 pm. If I drive at 70 km/h all the way there, buy a 66'er of vodka on sale for $38.95, then drive at 60km/h all the way back, can I feasibly be drunk by midnight?


No using a calculator!

the answer is definately yes

[Luc Duboi]

Originally posted by bdjuf


fuck no
m/s = meters per second

what kind of thing could go @ 40MILES a second?!?!?!

ok

[Luc Duboi]

Originally posted by bdjuf
40 m/sec, slowing down @ 2m/sec makes it 20 secs before it reaches zero.

the graph forms a rectangle triangle with 1 side measuring 40, and the other measuring 20, to find the surface of the triangle, wich represents the distance in meters, you do (40 X 20)/2 wich gives you 400 meters.

didnt you learn anything in physics class?

read the problem carefully.

40 meter per second reduces to minus 2 meter per second square (-2 m/s^2)

[Mr.Wong]

Originally posted by bdjuf
40 m/sec, slowing down @ 2m/sec makes it 20 secs before it reaches zero.

the graph forms a rectangle triangle with 1 side measuring 40, and the other measuring 20, to find the surface of the triangle, wich represents the distance in meters, you do (40 X 20)/2 wich gives you 400 meters.

didnt you learn anything in physics class?

It's slowing down by 2 meters per second squared, not 2 m/s.

Edit: Luc beat me to it.

[CDSmith]

Originally posted by bdjuf
the answer is definately yes

But having a right answer simply isn't good enough on this thread. Please illustrate the scientific formula you used to arrive at that conclusion. Please illustrate all calculations, trigonometry, calculous and vectors used.

[mjrools23]

need help with your HS math hw luc?

[buddyjuf]

Originally posted by Mr.Wong


It's slowing down by 2 meters per second squared, not 2 m/s.

Edit: Luc beat me to it.

meters per second squared is the general writing for of acceleration, but its slowing down @ 2 meters per second, only because its acceleration we put it squared, cuz thats how it is

ask a scientist, hell give you the same answer as me

[Thrawn$]

800+

[buddyjuf]

here, I made a pic for you

[CDSmith]

Originally posted by bdjuf
here, I made a pic for you

Yes, yes I see now that you are right by your calculations. I absolutely CAN be drunk by midnight.


thanks :D

[buddyjuf]

Originally posted by CDSmith
Yes, yes I see now that you are right by your calculations. I absolutely CAN be drunk by midnight.


thanks :D

no problem buddy, enjoy!

[Mr.Wong]

Originally posted by bdjuf



meters per second squared is the general writing for of acceleration, but its slowing down @ 2 meters per second, only because its acceleration we put it squared, cuz thats how it is

ask a scientist, hell give you the same answer as me

Ok, time to school.

x= x(not) + v(not)t + .5 at^2
x(not) = 0
v(not)= 40
t = 30
a = -2
t = 30

300 meters.

[buddyjuf]

Originally posted by Mr.Wong


Ok, time to school.

x= x(not) + v(not)t + .5 at^2
x(not) = 0
v(not)= 40
t = 30
a = -2
t = 30

300 meters.

your calculations show that the train would be going backwards from seconds 20(excluded) to seconds 30(included)
we both know that this cannot be true if the person uses the BRAKES

[Mr.Wong]

Originally posted by bdjuf
here, I made a pic for you

a^2+b^2=c^2

Area of that triangle does not = a+b/2

[buddyjuf]

Originally posted by Mr.Wong


a^2+b^2=c^2

Area of that triangle does not = a+b/2

what you are showing me is Pythagorus, that is to find the lenght of the segments...
the triangle area is represented by (A *TIMES* B)/2

[Mr.Wong]

Originally posted by bdjuf


your calculations show that the train would be going backwards from seconds 20(excluded) to seconds 30(included)
we both know that this cannot be true if the person uses the BRAKES

No, it would have stopped based on the problem. Of course it's not going backwards.

[Porndealer]

Originally posted by CDSmith
The liquor store is 12 km from my house, and it closes at 11 pm. If I drive at 70 km/h all the way there, buy a 66'er of vodka on sale for $38.95, then drive at 60km/h all the way back, can I feasibly be drunk by midnight?


No using a calculator!

Hell yeah, you probably left at 2pm you fuckin' alco

[buddyjuf]

Originally posted by Mr.Wong


No, it would have stopped based on the problem. Of course it's not going backwards.

thats why you need a graph,

u got owned buddy, u got owned

[Mr.Wong]

Originally posted by bdjuf


what you are showing me is Pythagorus, that is to find the lenght of the segments...
the triangle area is represented by (A *TIMES* B)/2

Yes, you're trying to find the length of the side, ie, the length of the train ride, not the area inside the triangle.

[buddyjuf]

lol
what does the lenght of that side represent?
we are trying to find the surface, wich represents the position in meters, compared to the initial position, wich is 0

[Mr.Wong]

Originally posted by bdjuf
lol
what does the lenght of that side represent?
we are trying to find the surface, wich represents the position in meters, compared to the initial position, wich is 0

Dude, distance is not equaled by the surface area. Where did you learn that? Distance is equaled by the side of the hypotenuse (sp)which is why you would use the Pythagorium (sp) theorm.

[buddyjuf]

Originally posted by Mr.Wong


Dude, distance is not equaled by the surface area. Where did you learn that? Distance is equaled by the side of the hypotenuse (sp)which is why you would use the Pythagorium (sp) theorm.

revise brudda, I studied in this, I know it like the back of my hand

Im honestly willing to bet any amount of money on this

BRING IT ON BITCHES

[Mr.Wong]

Originally posted by bdjuf


revise brudda, I studied in this, I know it like the back of my hand

Im honestly willing to bet any amount of money on this

BRING IT ON BITCHES

Ok, let's work on this here. You graph is showing that 2m/s is the hypotenuse, when it's actually supposed to be on the X access. The hypotenuse is the distance, which you are trying to find. Agree or disagree?

[buddyjuf]

its not the hypotenuse, its the "pente", as we say it in french....
whats the word for english, ARGH

its Y/X, I dont know what the english word is for it

the slope I guess? (I just checked a french english dictionnary)

[Mr.Wong]

Originally posted by bdjuf
its not the hypotenuse, its the "pente", as we say it in french....
whats the word for english, ARGH

its Y/X, I dont know what the english word is for it

the slope I guess? (I just checked a french english dictionnary)

The slope is the hypotenuse. Your graph is showing time as the distance. The 2 m/s should be on the x aixs, not as the slope. That's what you're trying to find.

[buddyjuf]

the graph is speed in the function of time

the vertical bar represents the speed in m/s
the horizontal bar represents the time in seconds
the diagonal represents the slope, wich represents the acceleration (-2m/s^2)
and the surface of the triangle represents the distance traveled

[thekebie]

Physics that uses numbers and calculations is gay. True Physics is all theory.

[buddyjuf]

Mr.Wrong
here you go

http://www.physicsclassroom.com/Class/1DKin/U1L4e.html

please read it carefully, it shows that the way I calculated is the correct way

[the Shemp]

[buddyjuf]

Originally posted by the Shemp

[mofo321]

actually it got negative decellaration
so it should go backwards

[buddyjuf]

Originally posted by mofo321
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

[cash69]

30 times farther then it was 30 seconds ago

[Luc Duboi]

I found interesting in BDJUF.

BDJUF, you just got yourself rekon by your greatness.



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

[Mr.Wong]

Originally posted by Overscore
d=.5(a×t^2)
d=.5(-2m/s^2×30s^2)

The train will travel -900m.

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?

[smack]

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?

[smack]

wow i was so fucking late on that.

[Lane]

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

how many of you are high school dropouts?