PHY102 hw help!?

NYSpeed Automotive NYSpeed Off Topic
1

hey…i know a lot of you guys on here are good with this kind of stuff…I for one, hate physics and it just doesnt click for me…:tdown: :\

can anyone help me with these problems? if so…and i see you out, i’ll buy you a shot, lol. thanks! :slight_smile:

1.) The potential difference between the accelerating plates of a TV set is about 25 kV. If the distance between the plates is 1.8 cm, find the magnitude of the uniform electric field in the region between the plates. (the answer should be in N/C)

2.)A point charge of 3.00 http://www.webassign.net/images/multiply.gif 10-9 C is located at the origin. How much work is required to bring a positive charge of 3.00 http://www.webassign.net/images/multiply.gif 10-9 C from infinity to the location x = 30.0 cm? (answer should be in J)

2

i could have answered these questions about 10 years ago. but i have systematically erased from my memory everything i learned about physics and calculus by killing my brain cells with lots and lots of beer. :gotme:

3

LOL, I just did those

for the first one, PE difference = E x distance

so the PE difference = 25,000v
the distance = .018m

so just sub in a figure it out.

For the second one, the PE difference at infinity is 0

So just figure out the PE from the given distance, and that - 0 will give you the answer.

So it will look like [(k x q1 x q2)/r]-0

What professor are you taking?

4

i have Dr. H Lou

thank you so much :smiley:

5

Ahh, I have Brewer’s night class :hang:

No prob.

6

r u doing the problems on web assign obviously…i wonder if they’re the same for zeng…just realized there are 2 assignments due today, and instead of being due at 11:59 like i thought they’re due at 5 , guess nows a good time to start lol

7

2 assignments??

My webassign says that there should only be assignment 2 due at 11:59 tonight…

Unless yours is different.

8

yea zeng must have changed the due date for the first assn to today, cuz this is the first one i’ve had to do, i dont know y its due at 5, o well i’m halfway done with the first one

9

yea.,.mine are due by 5pm…grR.

i only have one due
webassign wasnt working all last week and it says there was an assignment due last sunday…ugh.

thanks i solved those problems…:tup: :slight_smile:
ive been reading the book but i got so confused and frustrated, i just couldnt focus on one page in the book to see how to do them…

i need a phy tutor…this has nothing to do with my major but yet i have to take 2 semesters of it… :frowning:

im gonna be a PT…dealing with fixing peoples body parts, not trying to figure out voltage to some capacitor…lol :tdown:

Ooh…one more thing.what about this one?last one i promise.
Two point charges are on the y-axis, one of magnitude 3.0 http://www.webassign.net/images/multiply.gif 10-9 C at the origin and a second of magnitude 6.0 http://www.webassign.net/images/multiply.gif 10-9 C at the point y = 20 cm. Calculate the potential at y = 60 cm.

10

i can help u if u want, i got an A in 101, i havent done anything yet for 102 but it doesnt seem bad so far

11

Yea, I just read the summaries at the end of the chapters, and go to recitation. The book is very confusing, exp. with their examples that are way to complicated.

I hear you with having nothing to do with your major, it sucks :tdown:

Now onto organic before the superbowl :lol:

12

ha organic now thats a different story, test this week and i have no clue about spectroscopy nmr, mass spec, dude i’m fucked and this is the second time around

13

Do you have savino? First or second semester?

Yea man, I’ve been slacking way toooo much in that class.

14

i had savino last year, he is an awesome guy dont get me wrong, but when i got the tests i had no clue wat to do, he joked around to much and i didnt learn a thing, and this semester i purposly chose the 8am class to get away from richards, but he’s teaching that now to, he’s by far the worst and i’ve had them all between retaking both 201/202, gong, richards, savino

15

ok now i need some help…
2. [SerCP7 16.P.028.] A small object with a mass of 340 mg carries a charge of 35.0 nC and is suspended by a thread between the vertical plates of a parallel-plate capacitor. The plates are separated by 4.00 cm. If the thread makes an angle of 12.0° with the vertical, what is the potential difference between the plates?

thanks in advance

16

at canisius, we take a semester of spec and we cover ir, nmr, mass spec, uv-vis. what are u having trouble with?

17

Ok, this one was tricky.

To solve this problem, you need the formula:

V=EX

V is potential differece, E is electric field, X is the distance.

We have the distance, but we need to find E.

So, F = qE

E= F/q

Since the particle is suspended, there is no net force on it, so the F in the x direction has to sum to 0, and same for the y direction.

In the y direction, there is the y vector of the tension in the string, and weight of the particle.

So, Tcos(12)=mg

T=mg/cos(12)

Now the forces in the X direction are the x vector for the tension, and the force of attraction between the particle and the plate.

So Eq=Tsin(12)

E= Tsin(12)/q

Since we figured out T, we can sub that in.

E=(mg/cos(12))(sin(12)/q)
which simplifies to

E=tan(12)(mg)/q

So now just sub in E and x into the formula for V, and the problem is solved :wiggle:

18

holy shit i thought the shit i do at work gets complicated lol

:tup: to physics nerds

19

Alright, I can’t figure this one out.

  1. [SerCP7 17.P.012.] Suppose that you wish to fabricate a uniform wire out of 1.10 g of copper. If the wire is to have a resistance R = 0.300 , and if all of the copper is to be used.
    (a) What will be the length of the wire?
    m
    (b) What will be the diameter of the wire?
    µm

Edit: Nevermind, figured it out, if anyone needs to know also let me know.

20

o man bro that was a bitch u have to look up the density of copper online, i was fuckin pissed i sat there for 40 minutes thinking something was missing…then u solve for the volume of copper that u have and volume = length * crossectional area, solve for one variable and substitute it to the equation R=pl/A
EDIT: I saw ur edit lmao, o well too late someone else mite need the explanation