help with kinematics | Mathematics | Page 1

buoyant copper Jan 9, 2024, 11:45 PM

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Hello, we just started learning kinematics

Train speed is 72 km/h
It takes him 2 minutes to slow down to 0 km/h

How many meters away from the train station does he have to start slowing down to stop at the train station.

I've got 2 answers and I'm not sure which one is correcr
1200m and 3000m

untold waspBOT Jan 9, 2024, 11:45 PM

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digital patrol Jan 10, 2024, 12:50 AM

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buoyant copper Hello, we just started learning kinematics ``` Train speed is 72 km/h It takes ...

!show

untold waspBOT Jan 10, 2024, 12:50 AM

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buoyant copper Hello, we just started learning kinematics ``` Train speed is 72 km/h It takes ...

Show your work, and if possible, explain where you are stuck.

buoyant copper Jan 10, 2024, 12:50 AM

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digital patrol !show

What am I supposed to show

long pelican Jan 10, 2024, 1:12 AM

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@buoyant copper Identify the variables and since we're looking for displacement aka distance between we can use X = Xo + Vot + 1/2at^2

buoyant copper Jan 10, 2024, 1:13 AM

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long pelican <@1189720781010247841> Identify the variables and since we're looking for displa...

I got the answer already

long pelican Jan 10, 2024, 1:13 AM

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Can you show your work

buoyant copper Jan 10, 2024, 1:13 AM

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sure

buoyant copper Jan 10, 2024, 1:13 AM

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long pelican Can you show your work

print(
    (0-20**2)/(2*((0-20)/120))
)

long pelican Jan 10, 2024, 1:14 AM

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Uh

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is there something that's gonna pop up

buoyant copper Jan 10, 2024, 1:14 AM

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1200

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✌🏻

long pelican Jan 10, 2024, 1:14 AM

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?

buoyant copper Jan 10, 2024, 1:14 AM

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buoyant copper ```py print( (0-20**2)/(2*((0-20)/120)) ) ```

^^ this outputs the answer - 1200

long pelican Jan 10, 2024, 1:14 AM

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Hold on do u have it written it on paper

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It's hard to read math in text

buoyant copper Jan 10, 2024, 1:15 AM

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No, I wrote it in Pydroid

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I don't write things down on paper, only the final results

long pelican Jan 10, 2024, 1:15 AM

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Yea that's what makes it confusing

buoyant copper Jan 10, 2024, 1:16 AM

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I understand that more than writing it down on the paper, It's making me confused

long pelican Jan 10, 2024, 1:16 AM

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Idk what you wrote 🗿

buoyant copper Jan 10, 2024, 1:16 AM

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oh hold on let me

long pelican Jan 10, 2024, 1:16 AM

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I prefer doing on paper ye

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My physics teacher makes us do that

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Including on exams and such

buoyant copper Jan 10, 2024, 1:17 AM

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final = 0
v = 72/3.6
time = 2*60

(final-v²)/(2x(final-v)/time)

long pelican Jan 10, 2024, 1:18 AM

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Hmm

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1 second

buoyant copper Jan 10, 2024, 1:18 AM

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long pelican My physics teacher makes us do that

Same, I just help myself using python

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¯_(ツ)_/¯

long pelican Jan 10, 2024, 1:19 AM

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Are you multiplying 2 minutes by 60 or are you dividing

buoyant copper Jan 10, 2024, 1:19 AM

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Multiplying

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To seconds

long pelican Jan 10, 2024, 1:19 AM

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The SI unit you're using is km/h

buoyant copper Jan 10, 2024, 1:20 AM

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Converted to m/s

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72/3.6 = 20m/s

long pelican Jan 10, 2024, 1:20 AM

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Wait is km/h the same as m/s

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lol

buoyant copper Jan 10, 2024, 1:20 AM

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no
km/h
kilometers per hour
m/s
meters per second

long pelican Jan 10, 2024, 1:20 AM

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Oh alr

buoyant copper Jan 10, 2024, 1:21 AM

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I'm sorry thst I'm bothering you with this

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I just don't really understand math and physics so

long pelican Jan 10, 2024, 1:21 AM

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I have time dont worry

buoyant copper Jan 10, 2024, 1:21 AM

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And I have a test tomorrow, fortunately found the questions.

long pelican Jan 10, 2024, 1:21 AM

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Ah

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Well alr back to where we're at

buoyant copper Jan 10, 2024, 1:22 AM

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Yes.

long pelican Jan 10, 2024, 1:22 AM

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Alr so since we're using km/h

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We don't convert it to m/s because the majority is km/h

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let's just say that

buoyant copper Jan 10, 2024, 1:22 AM

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Sure 🙂

long pelican Jan 10, 2024, 1:23 AM

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If I had to convert 2 minutes into hours

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I would divide 2 by 60

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So you get 0.0333333 repeating decimal

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Let's just simplify that to 0.03

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I know it looks weird

buoyant copper Jan 10, 2024, 1:24 AM

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okay so

v = 72km/h
t = 0.03

long pelican Jan 10, 2024, 1:24 AM

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yes

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I dont know where you live but here in america we use X = Xo + Vot + 1/2at^2

buoyant copper Jan 10, 2024, 1:25 AM

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Oh what's Xo and Vot

long pelican Jan 10, 2024, 1:25 AM

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For displacement or distance in kinematics

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Xo = initial position
Vo = Initial velocity

t = time

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Vot is just multiplied together Vo and t

buoyant copper Jan 10, 2024, 1:26 AM

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initial position uhh, is that 0?

long pelican Jan 10, 2024, 1:26 AM

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Well

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To put it logically not really

buoyant copper Jan 10, 2024, 1:26 AM

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And how would we get Xo

long pelican Jan 10, 2024, 1:27 AM

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We just plug in the values and leave it as Xo

buoyant copper Jan 10, 2024, 1:27 AM

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Why are you using exclusive or for
at and 2

long pelican Jan 10, 2024, 1:27 AM

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Wdym

buoyant copper Jan 10, 2024, 1:27 AM

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xor

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bitwise operator

long pelican Jan 10, 2024, 1:27 AM

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Waht

buoyant copper Jan 10, 2024, 1:28 AM

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0010 0110 0101
1001 1011 1100

1011 1101 1001

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^ is xor

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We use power for a*t²

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at²*

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Sorry

long pelican Jan 10, 2024, 1:29 AM

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Alr so

mossy hemlock Jan 10, 2024, 1:30 AM

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this is not compsci

long pelican Jan 10, 2024, 1:30 AM

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X = Xo + Vo(t) + 1/2(a)(t)^2

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Yep

buoyant copper Jan 10, 2024, 1:30 AM

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X = Xo + Vo(t) + ½(a)(t)²

mossy hemlock Jan 10, 2024, 1:30 AM

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long pelican X = Xo + Vo(t) + 1/2(a)(t)^2

We used

long pelican Jan 10, 2024, 1:30 AM

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buoyant copper at²*

Idk but at^2 is just part of the equation

buoyant copper Jan 10, 2024, 1:30 AM

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mossy hemlock this is not compsci

but I'm confused, some people use ** or ² not ^ for power.

long pelican Jan 10, 2024, 1:30 AM

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Im sure you know how to find accleration right?

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Ohh

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Yeah ^ is to the power of __

buoyant copper Jan 10, 2024, 1:31 AM

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Yes 🙂 0-v/time

buoyant copper Jan 10, 2024, 1:31 AM

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long pelican Yeah ^ is to the power of __

Awesome, I got it

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a = v/t

long pelican Jan 10, 2024, 1:31 AM

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So we know that the final position is X = 0m

buoyant copper Jan 10, 2024, 1:31 AM

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Yes

long pelican Jan 10, 2024, 1:31 AM

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Because the train is stopping

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yes

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So we solve for Xo

buoyant copper Jan 10, 2024, 1:32 AM

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now uh we need to calculate the initial one, right?

long pelican Jan 10, 2024, 1:32 AM

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buoyant copper now uh we need to calculate the initial one, right?

Yea that's what the question asks for

buoyant copper Jan 10, 2024, 1:32 AM

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super 😉

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Let's do it.

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HOW WOULD it look like in the American way.

long pelican Jan 10, 2024, 1:33 AM

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So just write it down on paper and i'll check it out

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What?

buoyant copper Jan 10, 2024, 1:33 AM

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It's 2:33 am I can't

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😔

mossy hemlock Jan 10, 2024, 1:33 AM

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is it cuz ur lights off

long pelican Jan 10, 2024, 1:34 AM

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buoyant copper HOW WOULD it look like in the American way.

Just identify your values

Xo =
X =
Vo =
Vf =
t =
a =

Plug it in X = Xo + Vot + 1/2at^2

buoyant copper Jan 10, 2024, 1:34 AM

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yes and my parents are asleep

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But we haven't calculated Xo yet.

long pelican Jan 10, 2024, 1:34 AM

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.

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That's what we're trying to solve for

buoyant copper Jan 10, 2024, 1:34 AM

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But

long pelican Jan 10, 2024, 1:34 AM

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Even though the missing variable is on the other side, we can just leave the equation as it is

buoyant copper Jan 10, 2024, 1:34 AM

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long pelican Just identify your values Xo = X = Vo = Vf = t = a = Plug it in X = Xo +...

It's hard since I don't understand the american way

long pelican Jan 10, 2024, 1:35 AM

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@mossy hemlock @digital patrol hey guys can you take over I gotta go

long pelican Jan 10, 2024, 1:35 AM

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buoyant copper It's hard since I don't understand the american way

I gotta go hopefully you get it though

buoyant copper Jan 10, 2024, 1:35 AM

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long pelican I gotta go hopefully you get it though

😔

long pelican Jan 10, 2024, 1:35 AM

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Just plug in values and simplify

mossy hemlock Jan 10, 2024, 1:36 AM

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I would but the formula is not the way I would write it

buoyant copper Jan 10, 2024, 1:36 AM

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What's your formula

mossy hemlock Jan 10, 2024, 1:36 AM

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buoyant copper 😔

Did they give you a formula

buoyant copper Jan 10, 2024, 1:36 AM

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Nope

mossy hemlock Jan 10, 2024, 1:36 AM

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If they did it will be easier to use that one for you

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Otherwise you will get confused because people use different variables

buoyant copper Jan 10, 2024, 1:36 AM

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I can use yours, just gotta make sure It's characters not words like xo vo

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x, v not xo, vo that's what got me confused

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I assume xo is s
and vo is v

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a is a
and t is t

mossy hemlock Jan 10, 2024, 1:37 AM

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The o just means initial

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I'm pretty sure

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So it's x at 0 seconds or xo

buoyant copper Jan 10, 2024, 1:37 AM

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s = Xo
v = Vo
That's what we use 😆

mossy hemlock Jan 10, 2024, 1:37 AM

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OK

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Let me go to my computer in 6 minutes I'll try to help

buoyant copper Jan 10, 2024, 1:38 AM

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Okay 😆 ping me please

mossy hemlock Jan 10, 2024, 1:49 AM

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buoyant copper Okay 😆 ping me please

is the question all the info they gave

buoyant copper Jan 10, 2024, 1:49 AM

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mossy hemlock is the question all the info they gave

Yes

mossy hemlock Jan 10, 2024, 1:55 AM

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buoyant copper Yes

do u know if its constant acceleration

buoyant copper Jan 10, 2024, 1:55 AM

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mossy hemlock do u know if its constant acceleration

No It's not constant

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only v and t

mossy hemlock Jan 10, 2024, 1:56 AM

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buoyant copper No It's not constant

no

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im not saying

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nvm

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its constant acceleration

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ignore me

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im not saying a constant

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just ignore

buoyant copper Jan 10, 2024, 1:57 AM

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Ohh

mossy hemlock Jan 10, 2024, 1:58 AM

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buoyant copper Ohh

i got 1200 meters

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but im kind of bad at physics

buoyant copper Jan 10, 2024, 1:58 AM

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print(
    (0-20**2)/(2*((0-20)/120))
)

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Same

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It should be 1200

mossy hemlock Jan 10, 2024, 1:58 AM

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yk how to do it right

buoyant copper Jan 10, 2024, 1:58 AM

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kind of

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Now I do.

mossy hemlock Jan 10, 2024, 1:58 AM

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buoyant copper Jan 10, 2024, 1:59 AM

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Oh thank u 🙏🏻

mossy hemlock Jan 10, 2024, 1:59 AM

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these r like 3 simple 1d kinematics equations

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the triangle just means change in u dont need to write that

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x is displacement

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v is final velocity, vo is initial velocity, a is acceleration, t is time

#help with kinematics

0010 0110 0101 1001 1011 1100

0010 0110 0101
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