Friday
December 19, 2014

Posts by sandra


Total # Posts: 934

Physics
A simplified model for an erythrocyte is a spherical capacitor with a positive inner surface of area A and a membrane of thickness b. Use potential difference of 94 mV across the membrane and a dielectric constant K = 5.0. If the capacitance of the membrane is C = 0.15 pF, ...
March 4, 2010

Physics
I don't know how to approach this question... Any dielectric material other than vacuum has a maximum electric field that can be produced in the dielectric material before it physically or chemically breaks down and begins to conduct. This maximum electric field is called ...
March 4, 2010

Physics -- Repost
Homework Help Forum: Physics Posted by Sandra on Sunday, February 28, 2010 at 10:20am. Thank you for answering my previous questions! I have another one now in regards to the following question... An unknown potential difference exists between the inner and outer surfaces of ...
February 28, 2010

Physics
If someone can help, I'd really appreciate it!
February 28, 2010

Physics
Thank you for answering my previous questions! I have another one now in regards to the following question... An unknown potential difference exists between the inner and outer surfaces of the membrane of a cell. The inner surface is negative relative to the outer surface. If ...
February 28, 2010

Physics
I'm really unsure of how to approach this question... Polystyrene has a very low dielectric constant compared to most other solid materials. Therefore, we predict for a polystyrene slab pushed between the plates of a parallel plate capacitor: a. that the amount of charges ...
February 28, 2010

Physics
How does the capacitance of a parallel plate capacitor change when its plates are moved to twice their initial distance and a slab of material with dielectric constant К = 2 is placed between the plates to replace air? I think that the capacitance would be halved, is ...
February 28, 2010

algebra
how do i solve this? 16x^2,40xz^2,72z^2 I know its 8z GCF, but how is it done?
February 22, 2010

Trigonometry
Use the cofunction identities to find an angle x that makes the statement true: tan(2x-140) = cot(x+5)
February 17, 2010

Trigonometry
Factor 1-sin^3x
February 17, 2010

Physics and Calculus
Consider a charged ring of radius 27 cm and total charge 15 nC. We are interested in the electric field a perpendicular distance z away from the center of the ring. At what distance from the center of the ring does the electric field become maximum? Hint: The field for a ring...
February 15, 2010

science
what is the definition to molecule?
February 15, 2010

Physics
Consider a disk of radius 10 cm and positive surface charge density +3.7 mC/m2. A particle of charge -4.5 mC and mass 75. mg accelerates under the effects of the electric field caused by the disk, from a point at a perpendicular distance from the center of the disk. The final ...
February 14, 2010

Physics
Consider the limit of large distances, where a finite charged rod is observed at a distance that is very large when compared to the length of the rod. In this situation, the electric field best resembled that of a ... point charge ... it goes like r^-2 infinite line ... it ...
February 14, 2010

science
whether a material is magnetic or not depends on which of the following ??MANGET ,ELECTOMAGNETISM, ELECTRIC MOTOR, ELECTRIC GNERATOR, ELEC.INDUCTION, MAGNETIC FORCE,
February 11, 2010

Marketing
How can the lack of a physical good in a pure service affect efforts to promote the service?
February 9, 2010

Physics
Sorry, my question got answered in a previous post. Sorry for the repost!
February 6, 2010

Physics
Given a square of sidelength a = 4 cm. We place a charged particle at each corner, three of them carry + 2 nC of charge and one carries the same amount of negative charge. What is the magnitude of the electric field at the center of the square? I read a previous post for a ...
February 6, 2010

Physics- repost
ok..so how would we find the forces acting at the center of the field? There will be two forces acting, one form the negative and one from the positive charge right? But if we use Coulomb's Law here.. wouldn't we need a charge in the center? I don't understand how ...
February 6, 2010

Physics- repost
This answer was wrong though when I submitted it. If it's possible, can you please direct me to the mistake I'm making?
February 6, 2010

Physics- repost
Thank you for clearing that up! I'm getting a wrong answer once again for this question though.:( I tried it your way, but I have a feeling I'm making a mistake somewhere. Please help! Here's what I did: For the -ve charge located at the top right coner of the ...
February 6, 2010

Physics- repost
Posted by jude on Saturday, February 6, 2010 at 2:20am. Given a square of sidelength a = 5 cm. We place a charged particle at each corner, three of them carry + 2 nC of charge and one carries the same amount of negative charge. What is the magnitude of the electric field at ...
February 6, 2010

Physics
Hi, O tried this question, but I'm getting an answer of 0.99 which rounds to 1, but it was not given as one of the answer choices...can u tell me where I'm going wrong? What I did was used the following simplified formula: Volume*density*g =q*E ; where I solved for q. ...
February 6, 2010

physics
Is the point charge considered to have a charge of 1?
February 6, 2010

Phsyics
yes and i think that around the charged parallel plates..the electric field charge is zero so would the answer be between the charged parallel plates? I can't visualize the question...about the parallel plates..are they one negative and poistive plate..or both positive, ...
February 5, 2010

Phsyics
The electric field is constant in magnitude and direction for the following arrangement of fixed charges: -Close to a point charge -Close to a dipole -Far from a dipole, i.e., at a distance greater than 10 times the charge seperation distance d of the dipole -Around the ...
February 5, 2010

Physics 103
How do I solve this problem: You buy a 75W lightbulb in Europe where electricity is delivered to homes at 240V. If you use the lightbulb back in the USA at 120 V, what will it's power output be?
February 4, 2010

world history
WHY DID THE INDUSTRIAL REVOLUTION BEGIN IN BRITAIN
February 4, 2010

french
i don't know french that much but i think it should be Avant de choisir l'ecole ou , (like the others write it down)
January 27, 2010

math
there are 5 wate birds swimming in a pound if there are 3ducks and 2 geese at pond what fraction of the birds are ducks
January 12, 2010

college
Do students at various colleges differ in how sociable they are? Twenty-five students were randomly selected from each of three colleges in a particular region and were asked to report on the amount of time they spent socializing each day with other students. The results for ...
December 21, 2009

accounting
In your white paper presented to Tim and Anna, you shared with them the need to adopt a strategy that includes preserving current assets as well as creating future growth. As a result, you provided the tools they needed to consider to accomplish their goals: property and ...
December 16, 2009

pre algebra
1/2 +(2/3 / 3/4) +(4/5 x 5/6)=
December 7, 2009

Atmospheric Science
One of the earliest examples of primitive humans, Australopithecus, lived in Africa between about 4 and 1 million years ago. For what fraction of Earth history have hominids been around?
November 22, 2009

Atmospheric Science
The current magnitude of the greenhouse effect is measured by the difference between the emission from the surface and the emission from the top of the atmosphere, G=¦ÒTs^4 −¦ÒTe^4 ¡Ö 150 W m-2. What would be the required magnitude ...
November 20, 2009

Mathematics for Liberal Arts
You are on a TV show. You have been asked to either play a dice game five times or accept a $50 bill. The dice game works like this: If you roll a 1, 2 or 3, you win $46. If you roll a 4 or 5, you lose $22. If you roll a 6, you lose $85. Should you play the game? Use expected ...
November 20, 2009

11th grade
Where have canadians been involved in peacekeeping missions? where was their first mission?
November 19, 2009

11th grade
Where have canadians been involved in peacekeeping missions? where was their first mission?
November 19, 2009

Chemistry
How can you determine which acid solutions (all at 0.10 M) has the highest concentration of anions?
November 14, 2009

math
Suppose the standard deviation is 13.1. What is the variance?
November 13, 2009

statistics
Use this table to complete the tasks that follow it. Height (in inches) Frequency 50-52 5 53-55 8 56-58 12 59-61 13 62-64 11 Identify the class width. Identify the midpoint of the first class. Identify the class boundaries of the first class. Give the relative frequency for ...
November 13, 2009

Atmospheric Science
Wind is blowing from Lubbock to Abilene at 10 knots. Assuming a uniform and gradual slope between the two cities, what is the implied sign and magnitude of w resulting purely from this orographic influence? Will this wind warm or cool in transit, and by how much?
November 12, 2009

Atmospheric Science
The 15th floor meteorological observatory of the O&M building is 188 ft from the level of the main entrance. Assume that the temperature at the entrance is 25 degrees Celcius, that station pressure is 1000 mb, and the mixing ration is .010 kg/kg. What is the actual (station) ...
November 11, 2009

11th grade
9th grade 300 10th grade 400 11th grade 200 12th grade 400 all together 1200 students
November 6, 2009

math
what is the fraction as an equvalent decimal of 20/25
November 5, 2009

english
The number of boys presented is ten
October 20, 2009

Writing skills 1
psychological effect of nuclear weapons
October 13, 2009

Math
The price of a baseball glove is represented by the variable x the statement 'is at most' is represented by the symbol ≤ and then the price is $36.49 So the answer is x ≤ $36.49
October 2, 2009

Physics
A hockey puck is hit on a frozen lake and starts moving with a speed of 12.0 m/s. Five seconds later, its speed is 6.00 m/s. (a) What is its average acceleration? (b) What is the average value of the coefficient of kinetic friction between puck and ice? (c) How far does the ...
September 23, 2009

Quantitative Methods
I am trying to use the Goal Seek Method in Microsoft Excel but i keep getting a message that says "Cell must contain a value". Since the cell does contain a value what could be the error.
September 18, 2009

Math
The number of motor vehicles produced worldwide increased from approximately 57.5 million in 2000 to 60.3 million in 2003. Find the (percentage) change in motor vehicle production from 2000 to 2003.
September 14, 2009

Math
The number of motor vehicles produced worldwide increased from approximately 57.5 million in 2000 to 60.3 million in 2003. Find the percentage change in motor vehicle production from 2000 to 2003.
September 14, 2009

Aged College Student
The dosage of a certain medication is 1/4 ounce for every 50 pounds of body weight. How many ounces of this medication are required for a person who weighs 175 pounds?
September 14, 2009

Math
How to plot y=2x+4
September 14, 2009

Math
How to plot y=2x+4
September 14, 2009

Math
How to graph y= x+4
September 14, 2009

accounting
If you were considering extending credit to someone, what are some of the considerations you would recognize?
August 5, 2009

medical
why insurance companies need so much documentation and the reimbursement system is so complex?
July 29, 2009

Algebra
Diagonal brace. The width of a rectangular gate is 2 meters (m) larger than its height. The diagonal brace measures sqrt6m. Find the width and height.
July 23, 2009

algebra
Reduce the rational expression to lowest terms 1/15abc (5a^3b^5c^2) =3a^2b^4c Is this right. I reduced,and cancelled out exponents.
July 22, 2009

algebra
Reduce each rational expression to lowest terms 3x^2-9x+6/10-5x
July 21, 2009

algebra
Reduce rational expression to lowest terms 3t-6/8-4t
July 21, 2009

algebra
Write each number in standard notation 3.4 x 10^7 = 0.00000034 is this correct
July 21, 2009

pre-algebra
0.6x+ x ¡Ü1.4x-1
July 20, 2009

Statistics
A bank lobby has four video cameras positioned to view the entire lobby. any one of the four is sufficient to monitor the lobby. each camera functions independently and has a reability of 0.90, that is, the probability of functioning is 0.90. a bank robbery takes place. let a ...
July 20, 2009

algebra
A parabola has x-intercepts at 3 and 7, a y-intercept at -21, and (5,4) for its vertex. Write the parabola’s equation
July 19, 2009

algebra
Solve problem. Telephoto lens. find the image distance i for an object that is 2,000,000 mm from a 250-mm telephoto lens. tel formula is 1/f=1/o + 1/i 1/250=1/2,000,000 + 1/i 5i(1/250)=(1/2,000,000 + 1/i)5i 1/50i = 5i/400,000i + 5i/5i 1/10i = 5i/80,000i + 5i/5i I=8,000 Is this...
July 19, 2009

algebra
Fast food. If four out of five doctors prefer fast food, then at a convention of 445 doctors, how many prefer fast food? 4/5=x/445 5x=1780 x=356 please check if completed right
July 18, 2009

algebra
Bear population. To estimate the size Use a proportion to solve of the bear population on the Keweenaw Peninsula, conservationists captured, tagged, and released 50 bears. One year later, a random sample of 100 bears included only 2 tagged bears. What is the conservationist&#...
July 17, 2009

algebra
5x=1780 (4x445) 1780/5 x=356 checking to see if I completed right.
July 17, 2009

algebra
Use a proportion Fast food. If four out of five doctors prefer fast food, then at a convention of 445 doctors, how many prefer fast food?
July 17, 2009

algebra
Find a ratio, and simplify to lowest terms Rise and run. If the rise is 3/2 and the run is 5, then what is the ratio of the rise to the run?
July 17, 2009

algebra
Show a complete solution. Upstream, downstream. Junior’s boat will go 15 miles per hour in still water. If he can go 12 miles downstream in the same amount of time as it takes to go 9 miles upstream, then what is the speed of the current?
July 17, 2009

business
What is the interrelationship among the four financial statements? What methods are used to analyze an organization's financial condition?
July 14, 2009

American History
I just need help with the second question I already did the first one. I understand that some of the criticism are voteing, travel, I need a few more but I don't know what to put.
July 14, 2009

American History
What does American democracy mean to mean to you as an individual? What are some of the criticism of this style of government?
July 14, 2009

algebra
Reduce each rational expression to lowest terms. Assume that the variables represent only numbers for which the denominators are nonzero. 4x^2/2x^9
July 13, 2009

algebra
Simplify each complex fraction. Reduce each answer to lowest terms. ab+b^2/4ab^ 5 _______________ a+b/6a^2b^2
July 13, 2009

algebra
Reduce each rational expression to lowest terms. Assume that the variables represent only numbers for which the denominators are nonzero. a^2-b^2/a-b
July 13, 2009

algebra
5 is numerator/ y-3 is denominator y + 7/(2y-6) +1 y +7 is numerator, 2-y is denominator the whole thing +1
July 13, 2009

algebra
Perform the indicated operation (-2a²)/(3a²) X (20a)/(15a³)
July 13, 2009

algebra
Here are questions to worker question solve the problem. a) Rewrite the formula by factoring the right-hand side completely. b) Use the factored version of the formula to find N(3). c) Use the accompanying graph to estimate the time at which the workers are most efficient. d...
July 13, 2009

algebra
Worker efficiency. In a study of worker efficiency at Wong Laboratories it was found that the number of components assembled per hour by the average worker t hours after starting work could be modeled by the formula N(t)=-3t+23t^2+8t
July 13, 2009

algebra
Build each rational expression into an equivalent rational expression with the indicated denominator (-7yt)/(3x) =(?)/(18xyt)
July 13, 2009

algebra
Perform operation (-2a²)/(3a²) X (2a+2)/(15a³) Sorry this is my first time typing out math problems. Thank you for your help.
July 13, 2009

algebra
perform operatiion -2a²/ * 2a+2/ 3a² 15a³
July 13, 2009

algebra
Perform operation 3/a^2 x 2a+2/6
July 13, 2009

algebra
Perform operation 3/ * 2a+2/ a²+a 6
July 13, 2009

algebra
Reduce to simplest terms,rational expression -2x-8 ______ x^2+2x-8
July 13, 2009

Algebra
Build each rational expression into an equivalent rational expression with the indicated denominator. -7yt= ? ____ _____ 3x 18xyt
July 10, 2009

algebra
Which numbers cannot be used in place of the variable in each rational expression? 2y+1 ____ y^2-y-6
July 10, 2009

algebra
Decreasing cube. Each of the three dimensions of a cube with sides of length s centimeters is decreased by a whole number of centimeters. The new volume in cubic centimeters is given by V(s) = s3 - 13s2 + 54s -72. a) Find V(10). b) If the new width is s - 6 centimeters, then ...
July 10, 2009

math
Yeah I already figured it out thank you. I was wondering how you did it solved the problem I was getting fusterated b/c I tried it so many ways and I just wouldn't come up with an answer, I was way off the mult. choice. Once again thanks.
July 9, 2009

math
So what you did was mult. 230,000 by 1.06 right which I got 368000. But from there what do I do did you mult. 368000 by 21? I'm lost in that step right there.
July 9, 2009

math
Well you see that is what I did and but still don't come up with the answer these are my answer options. A)$427,867.75 B)$737,641.16 C)$828,813.61 D)$781,899.63 I even did this since there are 12mths in a year I mult. 12 by 21 which I got 252. So what is the answer though????
July 9, 2009

math
I can not solve this problem it's kind of hard for me can anyone please help me out. Thanks 1.If inflation is 6% a year compounded annually, what will it cost in 21 years to buy a house currently valued at $230,000? Round to the nearest cent.
July 9, 2009

comprehensive Gramer
My new coworker, a Muslim,is actually quite nice
July 6, 2009

college
DEFINE WHAT IS MEANT BY THE TERM''HUMANITIES''AND EXPLAIN WHAT DISTINGUISHED THE HUMANITIES FROM OTHER MODES OF HUMAN INQUIRY AND EXPRESSION. THEN LIST A CURRENT EX. OF EACH OF THE EXPRESSIONS OF THE HUMANITIES LISTED BELOW AND TELL WHY EACH EX. YOU GIVE ...
June 2, 2009

math
sandra bought 2 1/4pounds of lumbaar at 4.00 a lb. if a 7 percent tax was added, how much did she pay i know answer is $9.63 how did they get the answer
May 12, 2009

5th grade Math
i know right. this is hard and im in the 9th grade
May 4, 2009

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