# Posts by sandra

Total # Posts: 1,148

**Physics**

For the answer to the following post, do you mean that the frequency does not depend on the radius? Posted by Johnny on Saturday, March 13, 2010 at 5:49pm. The frequency of circular motion for a charged particle moving around in the presence of a uniform magnetic field does ...

**Physics**

An electron and a proton execute uniform circular motion in the presence of a uniform magnetic field. If the radius of the circle is the same for both particles, which of the following statements is true? A)Both particles move in the same direction; the electron moves faster ...

**Physics**

Gold ions (Au+) are accelerate to high speeds using electric fields. These ions are then passed through a region where uniform electric E and magnetic B fields are present. If the ions are traveling to the right, which configuration of E and B will serve as a velocity selector...

**Physics**

In the circuit below all light bulbs are identical. In order of brightest to dimmest the light bulbs are ... This is the best I could do, to try and replicate what the original circuit looks like : where the x's are just the wire; A,B, C, D, and E are the lightbulbs; and ...

**Physics**

If two resistors are connected in parallel, I know that they share the same voltage but how would you determine their current?

**Physical Science**

Why wouldn't you use this formula? Q=Qmax*e^(-t/RC)

**economics**

I need points and counterarguments on how globalization helps farmers in third world countries for my debate. I know that it opens up trade and has technological developments to create more efficient farming. But that's almost all I can think of.

**statistics**

randomly selected adult has IQ btween 110 and 120

**Physics**

Hi, thanks for answering. Apparently our professor wants us to do this question without using density. Is there another possible way to solve this question that you can direct me to?

**Physics**

Can the following equation be used to solve the question? R = ρ L / A ; find L.. or is there another way? Question: A rectangular piece of gold is 2.2 cm long and 2.4 cm wide. How deep is the piece when it displays a resistance of R = 1.06 μω for a current that ...

**Physics**

Thanks, so there wouldn't be any need to use the potential difference anywhere right?

**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, ...

**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 ...

**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 ...

**Physics**

If someone can help, I'd really appreciate it!

**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 ...

**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 ...

**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 ...

**algebra**

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

**Trigonometry**

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

**Trigonometry**

Factor 1-sin^3x

**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...

**science**

what is the definition to molecule?

**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 ...

**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 ...

**science**

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

**Marketing**

How can the lack of a physical good in a pure service affect efforts to promote the service?

**Physics**

Sorry, my question got answered in a previous post. Sorry for the repost!

**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 ...

**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 ...

**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?

**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 ...

**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 ...

**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. ...

**physics**

Is the point charge considered to have a charge of 1?

**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, ...

**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 ...

**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?

**world history**

WHY DID THE INDUSTRIAL REVOLUTION BEGIN IN BRITAIN

**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)

**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

**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 ...

**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 ...

**pre algebra**

1/2 +(2/3 / 3/4) +(4/5 x 5/6)=

**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?

**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 ...

**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 ...

**11th grade**

Where have canadians been involved in peacekeeping missions? where was their first mission?

**11th grade**

Where have canadians been involved in peacekeeping missions? where was their first mission?

**Chemistry**

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

**math**

Suppose the standard deviation is 13.1. What is the variance?

**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 ...

**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?

**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) ...

**11th grade**

9th grade 300 10th grade 400 11th grade 200 12th grade 400 all together 1200 students

**math**

what is the fraction as an equvalent decimal of 20/25

**english**

The number of boys presented is ten

**Writing skills 1**

psychological effect of nuclear weapons

**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

**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 ...

**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.

**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.

**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.

**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?

**Math**

How to plot y=2x+4

**Math**

How to plot y=2x+4

**Math**

How to graph y= x+4

**accounting**

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

**medical**

why insurance companies need so much documentation and the reimbursement system is so complex?

**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.

**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.

**algebra**

Reduce each rational expression to lowest terms 3x^2-9x+6/10-5x

**algebra**

Reduce rational expression to lowest terms 3t-6/8-4t

**algebra**

Write each number in standard notation 3.4 x 10^7 = 0.00000034 is this correct

**pre-algebra**

0.6x+ x ¡Ü1.4x-1

**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 ...

**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

**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...

**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

**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&#...

**algebra**

5x=1780 (4x445) 1780/5 x=356 checking to see if I completed right.

**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?

**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?

**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?

**business**

What is the interrelationship among the four financial statements? What methods are used to analyze an organization's financial condition?

**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.

**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?

**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

**algebra**

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

**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

**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

**algebra**

Perform the indicated operation (-2a²)/(3a²) X (20a)/(15a³)

**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...

**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

**algebra**

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

**algebra**

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

**algebra**

perform operatiion -2a²/ * 2a+2/ 3a² 15a³

**algebra**

Perform operation 3/a^2 x 2a+2/6

**algebra**

Perform operation 3/ * 2a+2/ a²+a 6

**algebra**

Reduce to simplest terms,rational expression -2x-8 ______ x^2+2x-8