Homework Help

Here's the question: 2 point charges q1 = +5.00 nC and q2 = -3.00 nC are seperated by 35.0 cm. What is the potential energy of the pair? The answer I got was 3.85 * 10 ^ -7. I ignored the signs (+) & (-) of the charges and reasoned that it's b/c the charges attract each other. But the answer in the book says it is -3.85 * 10 ^ -7 since energy must be added to seperate the charges. I thought potential energy is the energy needed to bring a particle from point A (infinity) to some finite distance B. If it's (-), then that means work needs to be done to bring these 2 together. But I reason that since they are opposite charges, they d o not need any ad…

I have just done a bit about DC motors in a lab, and now i have to derive the equation: E = K(fi)(omega) E = back emf K = Z/(2(pi) where z = number of conductors carrying current, I (fi) = magnetic flux (omega) = angular velocity of motor (rad/s) So I have to derive that from Faraday's Law, which I assume means: E = -N(d(fi)/dt) N = number of turns of a coil t = time? I don't have a clue where to start! Someone pleeese help ASAP!

I hate to use this site as "homework help" and i dont have the intention of having you all do my homework for me, however, i am confused about this question we have in physics class. we are supposed to write an essay on the subject of momentum and energy. the question is "How are energy and momentum properties of individual objects? How are they properties of the universe as a whole?" For the first part, i plan on just giving examples of how all types of energy (mechanical, chemical, electomagnetic, thermal, and nuclear) relate to objects, and how momentum relates to objects. however, i'm a bit lost on the universe part. i have kind of an idea for momentum, b…

All I need to know is: if you add water to vinegar, will it neutralize it? I've been having a debate about this with my younger brother. Quick answers (maybe a short explanation?) will be appreciated.

Hi, I just wanted to have some input from other people. I know that only secondary and tertiary alcohols are able to undergo halogenation (unless the primary alcohols are forced to do so with extreme heat and a regent like HBr)... I still can't figure out the reason primary alcohols aren't able to undergo halogenation. Does it have somethign to do with the electronegativities with the hydrogen atoms in a primary alcohol? Or am i totally headed in the wrong direction? I appreciate anyone's input on this Thanks!

I'm having some serious issues with my microbiology homework :s We have to calculate the decimal reduction time and I'm completely confused as to how to do this. If, say, we start with 800,000 cells initially, and after 60 minutes we have 4,000 cells remaining, how am I supposed to figure out the time at which 90% of the cells are dead?? I'm also having issues remembering how to calculate the number of moles of a compound from general chem. The formula I am using requires a mass when all we have is a volume and no density to convert it. I'm trying to calculate the number of moles in a 2mL solution of 25% NaCl. I need this value in order to determine the…

This is a homework question, it doen't have to be handed in, so there is no rush to answer, but the question has totally confused me! A steel bolt has a diameter of 6.35mm and a single start thread of pitch 1mm. The bolt is used to fasten together parts of a machine.When the parts are just in contact, without load on the bolt, the distance betwee the bolt head and the nut is 254mm. Estimate the tension in te bolt if the nut is tightened by 1/6 of a turn. State your assumptions. Would you expect your result to be larger or smaller than the actual load? Why? The answer is 4.3KN, larger. Any pointers/or a method would be greatly appreciated!

From homework: Below are the background info I need. (Right now I can't locate my background notes from class.) Carbohydrates: Types and their structures & function, monomers, polymers. Bonding between monomers: hydration synthesis, condensation, hydrolysis. What is an enzyme, What are they, what do they do, and how do they work? What is a substrate? Digestion, what, where, how, under what conditions Factors that affect enzyme action. Any help is appreciated.

To anyone who reads this, I am a highschool student and I came up with what I think is a simple and yet interesting science project. I would like to find out exactly how much people are interconnected on the internet. For example: Person 'A' is friends (at least through e-mail) with person 'B'. Person 'C' is friends with both person 'A' and peron 'B' but doesn't realize that person 'A' and person 'B' know each other. This is just an example. There are many other combinations that could make this experiment interesting. Ok, my request is that anyone who reads this to PLEASE send it (this entire message) to as many people as you would like via e-mail.…

Hello all, I have some problems with a question and was wondering if there is a brilliant mind out there that could help. It would be much appreciated, thank you. The question states: A chloride of phosphorus, A, contains 22.5% P by mass. Reaction of this compound with more chlorine gives another chloride, B, containing 14.9% Calculate the empirical formulae of the two chlorides.

All right, I have a project due this coming up Monday on Sea floor spreading, and the relation with the plate tectonics. Well, I have the basic concept that the lava flow on the sea floor causes the sea floor to spread and all that type of stuff. The part I don't understand is explaining how they proved this. It has something to do with the North Pole, and South Pole magnetic field switching every so many years. And due to iron in the lava, the patterns are different when the magnetic field changed. Something like that, I just don't quite understand it. Also, I don't know how I can explain this with 5 specific aspects for it happening, and all that. …

I have some Calculus assignments and I almost finish them, however there are 3 left and I have no idea How to do them, Can you please please help me, I need at least a C or B for this class. *Find the Derivative h(x) = x/(1-x)³ . Also find the coordinates of any point on the graph of the given function for which tangent line is horizontal. (I don’t know what this is) *Find derivative Y = cos(x-1) / (x-1) *Find a function form f(x) = a + bcoscx that is tangent to the line y = 1 at the point (0,1) and tangent to the line y = x + 3/2 – Ð/4 at the point (Ð/4 ,3/2)

Need some help with this assignment. Basically what I need to know out of the following list of substances which one (judged by quantity required) can buffer the water (with pH of 7) (the liquid with acid already added, which of the following substances will make pH level go back to neutral?): Baking Soda Tums Salt Pure Sugar Ammonia Cream Corn Starch Calcium Carbonate Chalk Basically in short english, which one of the substances listed above can make a liquid (water) with acid already in it return the pH level back to 7, with the least amount of the substance required? What is acid? A base, a buffer, neutralization reaction. I think I already u…

I've got to do a 9th grade science project, and i've decided i'm going to do the lift of a a thin wing and a fat wing. the one thing i need is the formula for lift. if anyone knows it please let me know.

I would like to know the name of the enzyme which is used for preventing coagulation of the milk?. Renil

** SORRY IF THIS IS UNDER THE WRONG SECTION ** I have a question in my homework and I am getting some dodgey fractions and I'm getting answers I shouldn't be. The question is: In the diagram, A is the point (7,0), B is (-3,-2) and C is (-1,8) The median CE and altitude BE intersect at J (a) Find the equation of CE and BD (b) Find the coordinates of J If possible give clear working and precise instructions when you reply. I will be really greatful for any help. The deadlines for reply is Tuesday. Thanx

Im waiting online so please if there is any1 currently online who knowz how to find the determinat of a matrix that is larger than 3 please teach or if you know a site where i can find such a thing please inform moi . Im waiting!!! thanx

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Hi, I am school now and I need to post some notes so I can get them when I am at home...we can't use email...it is locked out! So ya.... Cork, IRE: 51n54, 8w28, Ireland Calcutta, India 22 34 N 88 24 E 10:30 p.m. 1. Kyoto, JAPAN: 35n0, 135e45, Japan San Diego, CA (US): 32n43, 117w09, California Tegucigalpa, HON: 14n06, 87w13, Honduras (blike: yes, but i'm going to lock it. have you tried PMing it to yourself?)

I am doing a composition on Ghosts and I would greatly appreciate anyone that can tell me stories that they have experienced with ghosts. thank you PLEASE HELP ME!!!!!!! THANK YOU!!!!! :) :) :) :) :) :) :) :) :) :) :) :cooL

Hey guys, I am doing Civics survey. So, I need your help to answer these questions. Well, this might sound stupid but it's educational. For the following questions, answer each question as "YES" or "NO" and give at least one reason of what you think. 1) Should a specific dress code be introduced for the civics classroom? 2) Should eating/drinking be allowed in the civics classroom? 3) Should students have the right to leave their classroom for washroom or drink breaks without having to ask permission? 4) Should marks be deducted for late test/assignments in civics class? :help: :bs: I would appreciate if you reply these questions within …

Does anyone know the answer to this question? I cant find it in my book. Thanks to anyone who helps and thanks Tom for answering my last question. The question is "Describe the process by which glucose and amino acids are absorbed in the small intestine and carried away for use by the body?"

Does anyone know what the division of the trachea in the respiratory system is called? Thanks for the help.

Ok! We're learning how to factor in wind to an airplanes flight plan. I understand (finally) how to find it in a corrected situation. In a non-corrected situation I'm not so sure. Could someone shed some light on this problem.. (test tommorow) Airplane going 500 MPH on a bearing of 260 degrees encounters a 40 MPH wind blowing from 225 degrees. What is the new ground speed needed in order to get to his destination?

if sun went out how long would life on earth continue for before every thing died this is a quetion i must find the answer to for my home work could any one please help