The Official Homework Help Thread!

[aiyuu]

I was wondering if there was an answer because Im not sure if the way I'm thinking of solving it is right
[Spoiler] since they're asking for the distance the train travels after the third second until its at rest, I'd think you make Vi = 35m/s (speed of the train at 3 seconds), Vf = 0 (rest), and a = -2. Then I'd use the fourth equation and solve for d.
I got 306.25 for d [/spoiler]

can I ask you how you got a= -2? My acceleration was different for some reason

also thanks for this!

[pimo]

can I ask you how you got a= -2? My acceleration was different for some reason
also thanks for this!

what did you get? I'm not sure I'm right on this so I'd like to hear your answer too lol
Because in the first second it went 39m/s, then in the next second it travelled 37m/s, then it went 35m/s. so every second it got 2m/s slower, so I got a= -2 m/s^2

[aiyuu]

what did you get? I'm not sure I'm right on this so I'd like to hear your answer too lol
Because in the first second it went 39m/s, then in the next second it travelled 37m/s, then it went 35m/s. so every second it got 2m/s slower, so I got a= -2 m/s^2

Oooh I wrote the wrong things down. Yeah I got a = -2m/s^2 too but apparently the distance for this is supposed to be 289. :/ Even though I got 306.25 too... lol I think I might just check it up with the teacher, I have loads of other questions that I didn't get so I'm just gonna let it go. thanks for all your help! 

[pimo]

Oooh I wrote the wrong things down. Yeah I got a = -2m/s^2 too but apparently the distance for this is supposed to be 289. :/ Even though I got 306.25 too... lol I think I might just check it up with the teacher, I have loads of other questions that I didn't get so I'm just gonna let it go. thanks for all your help!

if you make Vi = 34 instead 35, youll get d=289

[aiyuu]

if you make Vi = 34 instead 35, youll get d=289

lol i finally figured it out, took ages tho. If you make three simultaneous equations for the three distances using the first formula. You can find vi = 40. Use the 2nd formula to get the total distance (400) and 400 - 111 = 289

[pimo]

lol i finally figured it out, took ages tho. If you make three simultaneous equations for the three distances using the first formula. You can find vi = 40. Use the 2nd formula to get the total distance (400) and 400 - 111 = 289

omg finally, what an adventure lol
Im curious, are you from England?

[aiyuu]

omg finally, what an adventure lol
Im curious, are you from England?

nope, ireland!

[pimo]

nope, ireland!

I should've guessed UK lol
Are you doing GCSEs?



You tie a long string to a cart on the ground. Explain why you can only pull the cart forward but cannot push the cart away with the string.

I don't get this, does anyone?

[Kawamashii]

Is this related to Physics?

 

I'm supposing that the reason is because the string can only be taut (i.e. have tension) if the force is being pulled away from the cart.  This is a result of Newton's Third Law (paraphrasing, "for every action, there's an equal and opposite reaction").  That is to say, when you pull forward on the string, the cart is also exerting a force on the string (but in the opposite direction), hence why the string becomes taut.  However, if you try to "pull" a string towards the cart, there's no force that can appear elsewhere to create tension on the string, hence why it remains limp.

 

I can tend to ramble on when it comes to Physics, so if I've been confusing about any of this, ask and I'll try to clarify.

[pimo]

Is this related to Physics?
 
I'm supposing that the reason is because the string can only be taut (i.e. have tension) if the force is being pulled away from the cart.  This is a result of Newton's Third Law (paraphrasing, "for every action, there's an equal and opposite reaction").  That is to say, when you pull forward on the string, the cart is also exerting a force on the string (but in the opposite direction), hence why the string becomes taut.  However, if you try to "pull" a string towards the cart, there's no force that can appear elsewhere to create tension on the string, hence why it remains limp.
 
I can tend to ramble on when it comes to Physics, so if I've been confusing about any of this, ask and I'll try to clarify.

thank you so much it just clicked in my mind lol! my teacher never explained it like that
Yes it's physics, I get the kinematics part of physics but forces just trips me over for some reason otl. Youre in college right? Do you study physics?

[Kawamashii]

thank you so much it just clicked in my mind lol! my teacher never explained it like that
Yes it's physics, I get the kinematics part of physics but forces just trips me over for some reason otl. Youre in college right? Do you study physics?

Yes, I'm in college as a Physics Major!  Glad I could help. (sun)

 

Forces can be confusing when you first start out with them.  I'm guessing you're having difficulty with vectors in particular?  I struggled with that while I was in high school, so don't be concerned if it takes getting used to.  Once you work with them for a while (which will be the rest of the course!) and realize that it's all splitting into components, it'll become second nature to you.

[pimo]

Yes, I'm in college as a Physics Major!  Glad I could help. (sun)
 
Forces can be confusing when you first start out with them.  I'm guessing you're having difficulty with vectors in particular?  I struggled with that while I was in high school, so don't be concerned if it takes getting used to.  Once you work with them for a while (which will be the rest of the course!) and realize that it's all splitting into components, it'll become second nature to you.

physics major :omg:
that's cool!
I love physics and math, but I've heard some stuff about how hard it gets in college lol I'm not sure whether to pursue it
For some reason I don't get tension! Like I understand the other forces but I guess I can't wrap my mind around that particular force
Anyways you should follow the thread and share your smarticle particles :ohbi:

[Kawamashii]

physics major :omg:
that's cool!
I love physics and math, but I've heard some stuff about how hard it gets in college lol I'm not sure whether to pursue it
For some reason I don't get tension! Like I understand the other forces but I guess I can't wrap my mind around that particular force
Anyways you should follow the thread and share your smarticle particles :ohbi:

I would certainly agree that Physics becomes harder in college, but I think that could be said of practically every major discipline!  As long as you work hard, you'll be fine.  Advanced Physics will require a lot of Math (though, only the computational portion of Math), so if you enjoy high school level Math, you'll likely enjoy the type employed in Physics.  Advanced Mathematics will lend itself away from computation and more towards proofwork (in a much different sense than high school geometry, however), but that's not very important if you're only interested in Physics.

 

Tension can be a very confusing concept to many, but it's not a fault of your own; it's actually taught wrong.  Though, understandably so, since the actual details of tension are complicated to grasp.  Although we tend to consider Tension a Force (and even measure it in Newtons), it's incorrect to consider it as such.  Tension itself is actually the result of atomic vibrations, with one portion of a rope pulling on another portion of a rope, and with the force on each portion of the rope being different at different points.  You can see why the actual details are obscured, since it's rather abstract; but for the purpose of being taught, tension as a force by an ideal, massless rope suits its purposes as far as Force Diagrams are concerned.  In most cases, you just need to suppose that Tension points in the direction of motion and it should work out.  I wouldn't really know a better way to put it, but I think it's the type of thing you get an intuitive grasp if you work with it enough.

[Jennifer]

do you guys use any sites to study for any of your AP social studies courses?

 

im taking ap world and i have my test tomorrow...

it's over 5 chapters of classic periods, and the test will definitely not be vague (i.e. the tradition and encounters book will be the whole test, not the general outlook)

i haven't even read the last chapter for this unit...

 

 

help....

i have a princeton ap review book, but it's way too general w/ the content

im using getafive to watch the lessons to help me... ;___;

Edited October 8, 2015 by shibal inu

[VANTE]

do you guys use any sites to study for any of your AP social studies courses?

im taking ap world and i have my test tomorrow...
it's over 5 chapters of classic periods, and the test will definitely not be vague (i.e. the tradition and encounters book will be the whole test, not the general outlook)
i haven't even read the last chapter for this unit...


help....
i have a princeton ap review book, but it's way too general w/ the content
im using getafive to watch the lessons to help me... ;___;

check out the OP! Depending on what course you have, I have different sites with textbook outlines or study guides and stuff :)

Edit: actually I never put in chapter outlines. Here's some I found from Google: https://wikis.engrade.com/strayerapworldhistoryout

Hope that helps! Edited October 9, 2015 by arctic_moss

[Mango]

do you guys use any sites to study for any of your AP social studies courses?

 

im taking ap world and i have my test tomorrow...

it's over 5 chapters of classic periods, and the test will definitely not be vague (i.e. the tradition and encounters book will be the whole test, not the general outlook)

i haven't even read the last chapter for this unit...

 

 

help....

i have a princeton ap review book, but it's way too general w/ the content

im using getafive to watch the lessons to help me... ;___;

there's shmoop but u need to make an account

[aiyuu]

I should've guessed UK lol
Are you doing GCSEs?

Nah, we don't have them here (Also sorry for late reply, I didn't see this lmao)

 

anyone want to help me out with this? it's q.8 a)

it's probably super simple but I can't think properly because I haven't slept at all

https://photos-5.dropbox.com/t/2/AADdw7EGWmrJ19mHw7ZHa_FDkzj3OnwsGagTMdkCRo-nAQ/12/146288868/jpeg/32x32/1/1444590000/0/2/2015-10-11%2018.17.56.jpg/COTh4EUgASACIAMgBiAHKAc/79wojcBg95XX91nKMcRPaTEdHDXUl_HZpTBdqPesnyE?size=1024x768&size_mode=2

answer x=4

Edited October 11, 2015 by aiyuu

[pimo]

Nah, we don't have them here (Also sorry for late reply, I didn't see this lmao)

 

anyone want to help me out with this? it's q.8 a)

it's probably super simple but I can't think properly because I haven't slept at all

https://photos-5.dropbox.com/t/2/AADdw7EGWmrJ19mHw7ZHa_FDkzj3OnwsGagTMdkCRo-nAQ/12/146288868/jpeg/32x32/1/1444590000/0/2/2015-10-11%2018.17.56.jpg/COTh4EUgASACIAMgBiAHKAc/79wojcBg95XX91nKMcRPaTEdHDXUl_HZpTBdqPesnyE?size=1024x768&size_mode=2

answer x=4

Ill try lol

sorry for the crazy fractions, fractions are hard to show on here lol

 

so to add/subtract fractions they need to have the same denominator. you can get the common denominator of (x+2) and (2x-1) by multiplying them, so the common denominator is (x+2)(2x-1)

multiply the top and bottom of 1/(x+2) by (2x-1) and multiply the top and bottom of q/(2x-1) by (x+2) so that have the same denominator, that gives you

(2x-1) / (x+2)(2x-1)  -  q(x+2) / (x+2)(2x-1)

 

then subtract the numerators

(2x-1) - q(x+2) / (x+2)(2x-1)

 

you could expand the (x+2)(2x-1) if you want and you'd get the denominator to be 2x^2 + 3x - 2 . 

 

Onto the 2nd part of the question. basically youre subtracting the same thing except q=1 

 

1 / (x+2)  -  1 / (2x-1) = 1 / (2x^2 + 3x - 2) [original question]

 

(2x-1) / (x+2)(2x-1)  -  (x+2) / (x+2)(2x-1) = 1 / (2x^2 + 3x - 2) [multiplied the fractions to have a common denominator]

 

(2x-1) - (x+2) / (x+2)(2x-1) = 1 / (2x^2 + 3x - 2) [subtracted]

 

(2x-1) - (x+2) / (2x^2 + 3x - 2) = 1 / (2x^2 + 3x - 2) [expanded the denominator]

 

both sides of the equation have the same denominator, so you can get rid of the denominator on both sides

 

(2x-1) - (x+2) = 1

 

and youd solve it like a normal equation

 

2x -1 - x -2 =1

x=4 

 

hopefully that helps, If I confused you Im sorry and please ask!

[Kawamashii]

do you guys use any sites to study for any of your AP social studies courses?

 

im taking ap world and i have my test tomorrow...

it's over 5 chapters of classic periods, and the test will definitely not be vague (i.e. the tradition and encounters book will be the whole test, not the general outlook)

i haven't even read the last chapter for this unit...

 

 

help....

i have a princeton ap review book, but it's way too general w/ the content

im using getafive to watch the lessons to help me... ;___;

I've never taken AP World History, but from my experience, Barron's Review Books had never let me down for comprehensive information.  They usually had more information than necessary, but the chances of them missing out any important details was very low.  Also, use your textbook if you've been assigned one!  There are certainly bad textbooks out there, but chances are that if yours is good, it'll contain a lot of useful information.

 

Something very important for AP courses is that you study periodically over long periods of time.  I'm sure there's a few people who can get away with cramming, but most people aren't a few people!  The history courses are definitely a fair share of work, but if you study or review a chunk of a chapter daily, you'll be mostly fine.  Do what you think is most reasonable.

 

 

 

Nah, we don't have them here (Also sorry for late reply, I didn't see this lmao)

 

anyone want to help me out with this? it's q.8 a)

it's probably super simple but I can't think properly because I haven't slept at all

https://photos-5.dropbox.com/t/2/AADdw7EGWmrJ19mHw7ZHa_FDkzj3OnwsGagTMdkCRo-nAQ/12/146288868/jpeg/32x32/1/1444590000/0/2/2015-10-11%2018.17.56.jpg/COTh4EUgASACIAMgBiAHKAc/79wojcBg95XX91nKMcRPaTEdHDXUl_HZpTBdqPesnyE?size=1024x768&size_mode=2

answer x=4

[spoiler][/spoiler]

Once you get it into single fraction form, you can solve for the numerator (since the denominators are equal) and it'll work out like any normal algebraic equation with one unknown.

 

Edit: Looks like pimo beat me to it!  I forgot to hit reply earlier, sorry, haha.

Edited October 11, 2015 by Kawamashii

[aiyuu]

Ill try lol

sorry for the crazy fractions, fractions are hard to show on here lol

 

so to add/subtract fractions they need to have the same denominator. you can get the common denominator of (x+2) and (2x-1) by multiplying them, so the common denominator is (x+2)(2x-1)

multiply the top and bottom of 1/(x+2) by (2x-1) and multiply the top and bottom of q/(2x-1) by (x+2) so that have the same denominator, that gives you

(2x-1) / (x+2)(2x-1)  -  q(x+2) / (x+2)(2x-1)

 

then subtract the numerators

(2x-1) - q(x+2) / (x+2)(2x-1)

 

you could expand the (x+2)(2x-1) if you want and you'd get the denominator to be 2x^2 + 3x - 2 . 

 

Onto the 2nd part of the question. basically youre subtracting the same thing except q=1 

 

1 / (x+2)  -  1 / (2x-1) = 1 / (2x^2 + 3x - 2) [original question]

 

(2x-1) / (x+2)(2x-1)  -  (x+2) / (x+2)(2x-1) = 1 / (2x^2 + 3x - 2) [multiplied the fractions to have a common denominator]

 

(2x-1) - (x+2) / (x+2)(2x-1) = 1 / (2x^2 + 3x - 2) [subtracted]

 

(2x-1) - (x+2) / (2x^2 + 3x - 2) = 1 / (2x^2 + 3x - 2) [expanded the denominator]

 

both sides of the equation have the same denominator, so you can get rid of the denominator on both sides

 

(2x-1) - (x+2) = 1

 

and youd solve it like a normal equation

 

2x -1 - x -2 =1

x=4 

 

hopefully that helps, If I confused you Im sorry and please ask!

ah thank you a lot! I don't know why that was so difficult to me lol

[hanmarie]

hello i made this acc because i really need help with some homework
if x^2 - x - 2 is a factor of 3x^3 + ax^2 - 10x + b find the value of a and b i keep gettinng different answers
i use the multiplying (x+k) method but keep getting different answers to the book a = 7 and b = -16

[pimo]

hello i made this acc because i really need help with some homework
if x^2 - x - 2 is a factor of 3x^3 + ax^2 - 10x + b find the value of a and b i keep gettinng different answers
i use the multiplying (x+k) method but keep getting different answers to the book a = 7 and b = -16

hihi welcome to OH :)

 

sorry for the late reply lol

I got a = 1 and b = -8, are those the answers? 

If you make a = 1 and b = -8, then you can factor 3x^3 + ax^2 - 10x + b into (x^2-x-2) and (3x + 4)

 

[spoiler]

basically what I did was factor the x^2 - x - 2 = (x - 2)(x + 1)

 

So now I know that when x is 2 or -1, 3x^3 + ax^2 - 10x + b must equal zero.

 

So I plugged those values of x into the equation and made them equal to 0.

 

when x = 2

 

3(2)^3 + a(2)^2 - 10(2) + b = 0

lots of simplifying

4a + b = -4

 

did the same for when x = -1

 

3(-1)^3 + a(-1)^2 - 10(-1) + b = 0

a + b = -7

 

now solve the simultaneous/ system of equations

a + b = -7

4a + b = -4

 

a = 1

b = -8

if you have any questions please ask ^^ [/spoiler]

Edited October 12, 2015 by pimo

[Mango]

is someone available to help me with physics?

[*lesigh*]

I'm desperate here. I'm in Algebra 2 and I need help with something involving Graphing Quadratics. I don't understand the concept at all and I can't really afford to fail this quiz, I tried to look at the resources but they were of no help because the teachers ran out of time and rushed into the material and only covered the mere basics, and my sister doesn't have any time to help me. PM me, I need some help with this.

Edited October 12, 2015 by Jessicant

[Athena]

I'm desperate here. I'm in Algebra 2 and I need help with something involving Graphing Quadratics. I don't understand the concept at all and I can't really afford to fail this quiz, I tried to look at the resources but they were of no help because the teachers ran out of time and rushed into the material and only covered the mere basics, and my sister doesn't have any time to help me. PM me, I need some help with this.

Just post it here. We try to give detailed explanations. If you want I won't give you the answer but I'll try to work you through it.