Hang Out and Post

[CAV of Gang Green]

Um, might I ask. Are you in collage. I'm just a freshman in high school. Sorry, can't help with that. Not without a proper calculator at least.

[Kuroida]

I'm in gr 11. And that's Ok....*commences the writting of random numbers* -_-

 

And wait. So do you know the basics of what I'm supposed to do/find? o.0

[-Ryan]

-coughcollegecough-

 

Anyway...

 

I trust everyone has had a good day so far?

[Kuroida]

gr 11 is college? .......or are YOU in college? :P If you are do you know how to do the question? If not then.....do you know how to do the question? :P

[-Ryan]

Yup, i'm in college. I'm the dean at Harvard. :D

 

 

[Tyler.]

I GRADUATED college years ago with straight A's in all advanced classes, now I'm the smartest man alive

[Kuroida]

If you're the smartest man alive can you help me with my question? :P

[Unstream]

Objects A, B

 

A: speed = constant = 10m/s

B: starts 5 secs after A, starts from rest, acceleration= 1.2m/s squared

 

QUESTIONS:

 

a) what time do the two objects meet (relative to A)

b) at what distance do they meet (relative to A)

 

HINT: use quadratic equation.

 

I don't even know where to start D: Any help would be greatly appreciated

Okay, since I don't want to solve this for you, I'll just tell you how I'd go about solving this problem.

 

First, you'll want to find the time that the two objects meet. You can use the formula:

Δx=(1/2)at^2+v(i)t

where "Δx" is change in position, "a" is acceleration, "t" is time, and "v(i)" is the initial velocity.

 

You know that Δx is going to be the same in both object A and B at that time, so you can reflect the right side of the equation over and use one side for object A and the other side for object B.

Basically, use:

(1/2)at^2+v(i)t=(1/2)at^2+v(i)t

And plug in the information for object A on one side and object B on the other. You should then get a quadratic equation, which you can use the quadratic formula to solve.

 

Hopefully this'll help. If not, just post again and I'll try to give you more hints ;)

[Kuroida]

....you are a GENIUS!! *bows down to your epicness*. Just hold on. I'm trying this now :P

 

*EDIT:

 

Ok. So when you plug everything in...would t be 5 for both cases?

 

So it becomes

 

(1/2)(0)(5)^2 + (10)(5) = (1/2)(1.2)(5)^2 + (V1)(5)

 

.....am I supposed to know V1 for object B? o.0

 

*EDIT (again):

oh wait!

 

So it becomes 10t = (1/2)(1.2)(5)^2 + (V1)(5).....uhh. I think I'm still stuck :S

[Unstream]

Oh, my bad, I misread the problem. It says that object B starts five seconds after object A.

 

So in that case, object A would have traveled 50m by the time object B starts, so to balance the equation you'll need to add 50 to the side you used to plug in the information with object B.

 

Edit:

v(i) for object B would be 0 m/s because it starts from rest.

 

Oh, and you may need to add 5 seconds to your final answer. Hold on, I'm actually going to try to solve it now, just to make sure I'm not misleading you :P

[Tyler.]

yeah, uh, Will helped you, and I knew it just didn't want to give it away :whistle:

[CAV of Gang Green]

And wait. So do you know the basics of what I'm supposed to do/find? o.0

 

Kinda. I'm in grade 9, so I got some of it figured out.

 

-coughcollegecough-

 

I understand the basics of vectors, but I can't spell college right.

 

Maybe it's because I'm watching Avatar while posting.

 

NO! JAKE TRIED TO HELP YOU! DON'T TELL HIM TO LEAVE AND NEVER COME BACK!

[Unstream]

....you are a GENIUS!! *bows down to your epicness*. Just hold on. I'm trying this now :P

 

*EDIT:

 

Ok. So when you plug everything in...would t be 5 for both cases?

 

So it becomes

 

(1/2)(0)(5)^2 + (10)(5) = (1/2)(1.2)(5)^2 + (V1)(5)

 

.....am I supposed to know V1 for object B? o.0

 

*EDIT (again):

oh wait!

 

So it becomes 10t = (1/2)(1.2)(5)^2 + (V1)(5).....uhh. I think I'm still stuck :S

No, "t" does not equal 5.

 

When you plug in everything and simplify, you should have:

10t=0.6t^2

 

Divide both sides by "0.6t", and....

 

Disclaimer:

That's how you'd do it if the objects started at the same time. Like I said in my last post, I misread the problem, so hold on...

[Kuroida]

wow. Thanks so much for all the help so far! I really appreciate it!

[Unstream]

Okay, here it is:

Since object B starts 5 seconds after object A, object A will have a 50m "head-start". To compensate for that, add 50 to the side with object B, so you'll have:

10t=0.6t^2+50

But keep in mind that'll mean you're neglecting the first 5 seconds of the scenario, so once you solve for "t", you'll have to add 5 seconds to your final answer.

 

So move the 10t to the other side...

 

***Edit***

Wait a second, the answers to that formula would be two unreal answers, so I might have to think about this again.

[Kuroida]

whoa whoa. How'd we get 50 again? o.0 Like how did you know it was a 50m head start? .....I'm sounding like an idiot aren't I? Sorry:(

 

*EDIT:

 

no wait I got it....I think

[CAV of Gang Green]

So many numbers. Since I'm sick and tired of school, and I want to enjoy my day off in peace without any school related stuff, I will avoid this topic until the answer to the problem is solved.

[Kuroida]

You have a day off?! You're so lucky! >.<

 

And so far:

 

using quadratic formula it becomes

 

square root 100-120 .....which gives me a negative number and you can't square a negative number....We're on the right track though

 

Maybe we're only supposed to add 5 and not 50....???

[Unstream]

Okay, let's approach this a bit differently (I know I have it right this time).

 

Let's go back to this equation:

(1/2)at^2+v(i)t=(1/2)at^2+v(i)t

 

Plugging everything in...

(1/2)(0)t^2+10t=(1/2)(1.2)t^2+(0)t

 

Simplifying...

10t=0.6t^2

 

But wait! The original problem says that object B starts 5 seconds after object A. That's very important. So the time for object A is 5 seconds more than the time for object B, so on the side where you're calculating object A, replace the "t" with "t+5".

 

So you'll get something like this:

10(t+5)=0.6t^2

 

Think you can take it from here?

 

I have the answer, so if you want, just post what you get and I'll confirm, though everything's there for you, so it's basically just algebra from this point on.

[Kuroida]

a) t= 20.69sec?

 

b )

 

use equation d= V1t + 1/2a(t)^2

 

d= 10(20.69) + 1/2 (0) (20.69)^2

 

d= 206.9?

 

*crosses fingers* >.<

[Unstream]

I think so. Either that or it's 25.69 seconds.

 

Bah. I'm too tired to think any harder on this x_x

I'll post again if I have an epiphany though :P

[Kuroida]

Oh right. Forgot to add 5. Either way THANK YOU SO MUCH!!! I don't believe in religion but you are the new god XD

[The Score in Blue]

Are we all discussing maths? My exam's in 7 days ah! Any study tips?

[Kuroida]

yeah. Avoid word problems at all costs -_-

 

But what really helps me learn is by doing practice questions...

 

And we were discussing physics. My exams aren't for a few more months....and I don't even have math this semester o.0 Good luck on your exams though!

 

And I have to go to bed now. Unsteam I still can't thank you enough :P

[livvy]

Eep! I missed Physics help? But I love Physics! D=

 

Still, glad Will could help you, Kuro. He's a smart one. ^_^