Member of the Month

KilaTsunami
October, 2024

Online

Welcome to the Newschoolers forums! You may read the forums as a guest, however you must be a registered member to post. Register to become a member today!

Feel like a genius by clicking here

profile picture
GatoGordo
Posts: 1496 - Karma: 10
So i have basically become retarded, and i can't remember how to solve this problem for physics. I will give you some good karma, and i hope others will give you some of you help me out here. I need the answer as quickly as you can solve it, but it's not that hard, so it shouldn't take long. Here it is:

Imagine a ball rolling against friction.  We don’t know the initial velocity but it comes to a stop after 3.33 seconds after having rolled 6.75 meters.  Use that information to find the initial velocity and the acceleration of the ball.


Try to use one of the three Galileans equations to solve it, because that is what we use.

Feb 14 2008 5:25PM
0 0
profile picture
powderdrunkie
Posts: 2034 - Karma: 976

seven

Feb 14 2008 5:43PM
0 0
profile picture
yellav
Posts: 10056 - Karma: 1,217
sixty nine
Feb 14 2008 5:44PM
0 0
profile picture
Microcosm
Posts: 4765 - Karma: 153
Vo= 2.027 m/s = Initial Velocity
a= 0.85 m/s = Acceleration
X= Final distance
Xo= Initial Distance
V= FinalVelocity

X=Xo+ Vt
6.75=0+V(3.33)
V= 2.027 m/s

V=Vo + at
0= 2.027) + a(3.33)
a= 0.609 m/(s^2)

Hopefully I didn't mess anything up, I'd check the math again.
Feb 14 2008 5:49PM
0 0
profile picture
comeatmebro
Posts: 10720 - Karma: 66
I DO NOT FEEL LIKE A GENIUS!!!

i feel retarded
Feb 14 2008 5:58PM
0 0
profile picture
Microcosm
Posts: 4765 - Karma: 153
haha, don't sweat it. it's pretty simple, if someone taught it to you I'm sure you could learn those formulas pretty quickly. it's just "plug and chug" as all the teachers like to say.. just look at the variables in the equation and use the numbers in the question to find the missing variables. plug in and solve.
Feb 14 2008 6:00PM
0 0
profile picture
Joe_
Posts: 648 - Karma: 14
haha, if the acceleration is positive then the ball will never stop rolling, it will only speed up. gatogordo, are you given the friction coefficient of the ball?
Feb 14 2008 6:02PM
0 0
profile picture
Microcosm
Posts: 4765 - Karma: 153
word, negative acceleration then. maybe I messed up something and switched a sign somewhere. you don't need the friction coeff. to solve this one though because you have the time it took to stop etc. idk, I'm supposed to be studying for this damn wavelengths test here..
Feb 14 2008 6:04PM
0 0
profile picture
Joe_
Posts: 648 - Karma: 14
^yea good call you just switched a sign, the acceleration is -.609 m/(s^2)
Feb 14 2008 6:05PM
0 0
profile picture
comeatmebro
Posts: 10720 - Karma: 66
ah i see, seems easy then. looks hard though. i haven't had physics yet, it seems like a fun class though.
Feb 14 2008 6:10PM
0 0
profile picture
GatoGordo
Posts: 1496 - Karma: 10
Thanks a lot Microcosm, everybody should give him some good karma.
Feb 14 2008 6:17PM
0 0
profile picture
Alex_G
Posts: 11902 - Karma: 1,019
This is why he goes to Stanford everybody.
Feb 14 2008 6:23PM
0 0
profile picture
Microcosm
Posts: 4765 - Karma: 153
thanks, give to hoseph too for helping out as well!
yeah, physics can be fun but incredibly frustrating as well.

Feb 14 2008 6:24PM
0 0
profile picture
mistaskia
Posts: 1252 - Karma: 32
yea i should be studying for a wavelengths test right now too!!! haha physics can suck sometimes, especially when the teacher sucks like mine. 
Feb 14 2008 6:58PM
0 0
profile picture
Microcosm
Posts: 4765 - Karma: 153
my teachers all right, but this test will be fun.. standing waves and types of waves and all that stuff?
Feb 14 2008 9:28PM
0 0
profile picture
MCIRONCOCK
Posts: 3094 - Karma: 30
Worst. Class. Ever.
Feb 14 2008 10:14PM
0 0
profile picture
oiECSoi
Posts: 1447 - Karma: 10
yeah my phsyics teacher says that.... he's a complete douchebag and is a slight crack addict
Feb 14 2008 10:25PM
0 0
profile picture
mistaskia
Posts: 1252 - Karma: 32
hahaha i just failed the shit out of my test, how did u do?
Feb 15 2008 9:54AM
0 0
profile picture
WONTON
Posts: 6951 - Karma: 55
physics isnt too bad, especially just basic kinematics
Feb 15 2008 11:14AM
0 0
profile picture
mski
Posts: 4791 - Karma: 3,803
stuffs no fun, dont worry, you'll have a project end of the year that will save your grade....as long as its highschool.
Feb 15 2008 12:02PM
0 0
profile picture
bigdaddytmac
Posts: 1448 - Karma: 14
He just left the sign out of the very last part. It is correct just make the acceleration negative.
Feb 15 2008 12:07PM
0 0
profile picture
Microcosm
Posts: 4765 - Karma: 153
It went pretty well! sorry to hear yours didn't. I was pretty happy because the rest of the tests haven't been too great and I feel like I knew this one. either way I don't know for sure until I get the test back.
Feb 15 2008 4:07PM
0 0
profile picture
Lineskiah11
Posts: 2029 - Karma: 21

i took the same test as mistaskia and it sucked balls. it was realy easy math but had all these detailed questions on interference and random stuff that you wouldnt know unless you read the chapter 5 mins before class. the problem is our teacher is nice he just doesnt teach sometimes and thinks we should magically know it

Feb 15 2008 4:18PM
0 0
profile picture
oiECSoi
Posts: 1447 - Karma: 10
hmmm... sounds like one of the teachers we had last year. doesnt it?
Feb 18 2008 11:25AM
0 0
profile picture
kepler.
Posts: 8761 - Karma: 139
Physics is the ONLY class I've ever enjoyed in school. It teaches you about all this cool shit going on all around you. Hopefully you get a teacher that doesn't employ "plug and chug" then it might not be so fun. My teacher made it make sense and I understand why I use those formulas (especially when we take 3 weeks to derive all of them)

I can't stress enough for people who don't really like school, to take phyics. Its a great class
Feb 18 2008 11:38AM
0 0
profile picture
Pippin
Posts: 4846 - Karma: 661
now when you get to 3-d collisions, now thats fun
Feb 18 2008 11:51AM
0 0
profile picture
solitaryman
Posts: 3578 - Karma: 123
naww i deffinitely don't feel like a genious
Feb 18 2008 11:59AM
0 0
profile picture
Bepo
Posts: 8195 - Karma: 17
Dunno if you already submitted it or whatever, but this is wrong.  The formula X=Xo+ Vt only works if there is no acceleration.  It's basically Velocity = Distance / Time.  The right formulas to use would be

V = Vo + A * T
X - Xo = Vo * T + (1/2) * A * (T)^2

You know everything except Vo and A, so solve using a system of equations.  You should get Vo = 4.05 m/s and A = -1.217 m/s^2 .
Feb 18 2008 2:58PM
0 0
profile picture
Leo.
Posts: 508 - Karma: 17
such a misleading title...
Feb 18 2008 4:02PM
0 0
profile picture
salomonskiier12
Posts: 2862 - Karma: 19
i think that the acceleration would be 0 because it is already moving at a constant speed.
Feb 18 2008 5:40PM
0 0
All times are Eastern (-5)