Saturday

April 19, 2014

April 19, 2014

Total # Posts: 1,305

**trigonometry**

tan60=2 tan30/1-tan^2 30 sqrt(3)=I'm confused of that 2 but i guess it means to multiply. again.. sqrt(3)= (2) sqrt(3)/3 / 1- sqrt(3)/2 ^2 now i dont know how to square tan . if u can show me in details i would appreciate it. this is just a practice problem and i want to l...

**French**

Hi, I'm wondering if any of you could lead me to the mark scheme for the IGCSE French Reading and Directed Writing Paper 23 May/June 2010? Any help would be appreciated. Thank you.

**Math**

By solving the equation x/8 + x/10 = 90. Sorry for the late response.

**Math**

In jar 1, 1/8 of the marbles are white. In jar 2, 1/10 of the marbles are white. Since the jars are filled with an equal amount of marbles, take this value to be x. Therefore, x/8 + x/10 should equal to 90, the total number of white marbles. From this, we get x = 400 marbles a...

**Physics**

It's from a textbook, the answer I'm supposed to get is 5250 Joules..

**Physics**

A bungee jumper of mass 60 kg jumps from a bridge tied to an elastic rope which becomes taut after he falls 10 m. Consider the jumper when he has fallen another 10 m and is travelling at 15 m/s. Work out how much energy is stored in the rope. Take g=10 m/s^2 and ignore air res...

**Physics**

At t = 0, a 785 g mass at rest on the end of a horizontal spring (k = 125 N/m) is struck by a hammer, which gives the mass an initial speed of 2.70 m/s. (a) Determine the period of the motion. T= .4979201367s Determine the frequency of the motion. f= 2.008354 Hz (b) Determine ...

**Math**

There are 4 black marbles and 5 red marbles in a bag. If you reach in and randomly select 2 marbles, what is the probability that both are red? Explain your reasoning.

**6th grade**

12% is the same thing as .12 So .12*(number of sixth graders) = 24 number of sixth graders = 24/.12 = 200

**chem**

what is the name of ONO and what is its charge

**chemistry**

complete and balance the following equation: CoCl*6H2O+ NH4Cl+ NH3+ H2O ---> [Co(NH3)5Cl]Cl2+ H2O

**chem**

you used a pencil to mark the chromatography paper since the carbon in the "lead" pencil does not dissolve in the solute. why does carbon not dissolve? what type of pen (ink) will also not produce a chromatogram when water is used as the solovent? explain using princ...

**chem**

the total pressure of n2o4 and no2 IS 1.38 atm. if kp is 6.75(25 C) calculate partial pressure of NO2 in the mixture. 2NO2<---> n2o4

**C++**

I have no idea how to construct this program. Any help is appreciated. Thank you. In a population, the birth rate is the percentage increase of the population due to births and the death rate is the percentage decrease of the population due to deaths. Write a program that disp...

**physics**

An undersea research chamber is spherical with an external diameter of 3.70 m. The mass of the chamber, when occupied, is 26000 kg. It is anchored to the sea bottom by a cable. What is the tension in the cable?

**Chemistry**

lawls

**Chemistry**

tony is stupid

**Earth CRYience**

Assume a parcel of air on the surface with a temperature of 29 degrees Celsius with a relative humidity of 50%. If the parcel rises at what altitude should clouds form?

**math**

no typo. I tried the quadratic equation and got -.986 and 1.24. Does this mean there are no real roots (an option in the question). Also, for the question 4x^2-12x+9, is the real root (2x-3)?

**math**

What are the real roots of the quadratic function 4x^2-x+5?

**4th grade**

Let n= a number n-5

**3rd grade**

Eleven and five. 11+5=16 11-5=6

**algebra**

Distribute. 40x-16=84 Add 16 to both sides. 40x=100 Divide both sides by 40. x=2.5

**English**

Thank you.

**English**

Complete the sentence by writing the correct form of the word in parentheses. You may not need to change the form that is given. 1. She made her fortune in the ____ market before she became a full-time philanthropist. (security) Would the correct answer be "securities&quo...

**MAT 116**

You are on the right track. Be sure to use the order of operations (Parentheses, Exponents, Multiplication, Division, Addition, Subtraction). Multiply the 8 and 15 to get 120, then multiply the 6 and 3 to get 18. That leaves 120-18, which you would simply subtract to get your ...

**calculus**

Alright. a. y1+y2 should be set up as follows: (x^2+3x-1)+(x-5), which equates to x^2+4x-6 You just combine the like terms. b. (x^2+3x-1)-(x-5) For this one you need to distribute the negative, to get x^2+3x-1-x+5, then combine like terms. c. (x-5)(x^2+3x-1)= x^3+3x^2-x-5x^2-1...

**Earth Science**

what is the dewpoint temperature of a kilogram of air when a psychrometer measures an 8 degree Celsius dry-bulb temperature and a 6 degree Celsius wet-bulb reading?

**C++**

Write a statement that passes the value 4 to the function below and assign it's return value to the variable result. Thank You. int cube(int num) { return num*num*num; }

**Statistics**

My apologies, the figure got messed up Paper shredders --------------- 75 115 118 287 250 300 50 Calculators -------------- 110 140 165 90 230 97 269

**Statistics**

The figures below represent the prices (in dollars) for both paper shredders and calculators. At the 0.10 level of significance, can it be concluded that the variance in price differs between the two types of machines? Paper shredders | Calculators ----------------------------...

**Earth Science**

What are the effects radiation has on the heating of land and water? Thank You.

**Earth Science**

What are the primary heat absorbing gases in the atmosphere? What wavelength of radiation do they absorb?

**chemistry**

what is the reaction equation when maleic anhydride is combines with granular zinc and HCl propose structures for the products you would obtain by treating fumaric acid, cinnamic acid, and butynedioic acid with zinc and HCl. write balanced equations for the reactions.

**Earth Science**

What are the minimum and maximum durations of daylight at a latitude of 39 degrees north? Thanks.

**Earth Science**

What causes the intensity and duration of solar radiation received at any place to vary throughout the year?

**chemistry**

AgI (aq) + NH3 (aq) -->

**chemistry**

how can AgCl(s) be dissolved completely? write an equation for the reaction

**Statistics**

find the 90% confidence interval for the variance and standard deviation of a sample of 16 and a standard deviation of 2.1 Assume the variable is normally distributed.

**Statistics**

Thank you so much!

**Statistics**

For a sample group of 22, the mean is 86 with a standard deviation of 5. What is the 90% confidence interval of the true mean of the sample? Can you please explain the steps you used to get the answer. Thanks.

**chemistry**

ok thank you:)

**chemistry another add on**

c)what is the pH after the addition of 1.0 mL of 0.10 M NaOH to 15 mL of the original solutiom.... i dont really need a im pretty sure my answer is right but should i really be getting the same answer for b and c?

**chemistry**

b) what is the pH after the addition of 1.0 mL of 0.10 M HCL to 15.00 mL of the solution?

**chemistry**

what is the pH of a solution prepared by adding 20.00 mL 0f a 0.10 M acetic acid and 10.00 mL of 0.10 M sodium acetate

**chemistry**

net ionic equations of nitric acid with CO3 2- and with PO4 3-.

**chemistry**

a titration is done with with 25.00 mL of a .1500 M HBrO solution is titrated with .1025 M NaOH. Ka for HBrO= 2.0 x10^-9. The pH of HBrO before the titration begins is approx. closest to which of the following a. 0.82 b. 4.76 c. 8.70 d 10.60 e. 13.01 the answer is b 4.76 but how?

**chemistry**

the Ksp for CaF2 is 3.9*10-11. assuming that calcium flouride dissociates completely upon dissolving and that there are no other important equilibria affecting the solubility, calculate the solubility in pure water, of calcium floride in m/L and in g/L

**physics**

^ That is just an equation, it does not even answer the question.. I don't mean to be rude but even if you know the equation you can't answer the question if you do not know how to apply it.

**algebra**** 1**

x= 51428571.43 square miles

**PHyiscs**

A HELICOPTER hovering above a forest fire dumps a large bucket of water. How far does the water fall in the first 3.0 seconds t=3.0s

**chemistry**

In the movie "The Raiders of the Lost Arc", Indiana Jones and his guide play catch with a gold idol. The idol had a volume of about 1.30 L. In order to determine whether they could really play catch with the idol, calculate the weight (in pounds) of the idol. The den...

**Math(word problems)**

4.Tracie invested $x at 7% and $y at 6%. Write algebraic expressions for: a.the total amount of money invested b.the interest earned at 7% in one year c.the interest earned at 6% in one year d.the total interest earned in one year

**math**

1.)Explain why ironing boards always remain parallel to the floor and can be adjusted for people of various heights. You may want to consider the following: a.)The legs of the board are built so that AD = BD and DE = DF, and ADF and BDE are straight lines as shown. b.)Which an...

**Chemistry**

what's #10

**physics**

A cylindrical space colony 8 km in radius and 60 km long has been proposed as living quarters for future space explorers. Such a habitat would have cities, land and lakes on the inside surface and air and clouds in the center. All this would be held in place by the rotation of...

**programmning code**

Is this code right? Declare Integer days, counter = 1 Declare Real penny = 1, salary, total = 0 Display "Enter a number of days." Input days Display "Days",TAB,"Salary While counter <= days Set salary = penny/100 Display counter, TAB, salary Set pen...

**Chemistry**

The element niobium has bcc packing with a body-centered cubic unit cell. The volume of the unit cell is 3.59 x 10-26 L. Calculate the density (g/cm3) of the element

**5th grade**

Hello there Read the problem as it says. Variable "n" raised to the 10th power is equal to 27.

**Stats**

What is the probability that a simple random sample of 56 special orders will provide an estimate of the population proportion of special orders specifying the color black that is within plus or minus .05 of the actual population proportion,assuming p = .36? In other words, wh...

**physics**

I think you mean third second

**language**

lol are you posting under several diff names for the same kinda homework?

**biology**

Replication of the E. coli chromosome takes 40 to 45 minutes, but the organism has a generation time of 26 minutes. How does the cell have time to make complete chromosomes for each daughter cell? For each granddaughter cell? my reponse was that the cells don't fully repli...

**Chemistry**

bump

**Chemistry**

bump

**his 135**

This is one of the more helpful posts I found after finding this site on google, and it (like most others) is almost useless in its content related to the 1960's subculture.. and it is also filled with rude people telling its customers to search elsewhere.. I too will take...

**chemistry**

NS6 P2S6 C? Phosphorus tetrabromide

**Global Studies**

actually if you state the documents out like that, you LOSE points and wont be able to go in the expanded core. just say "so and so stated this" and then in parentheses, say the document number. believe me ive been doing this without knowing, and my ap teacher just t...

**Chemistry *URGENT***

URGENT help! 3. A rock sample was dated using potassium-40, Neasyrenebt ubducated tgat 1/8 of the original parent isotope is left in the rock sample. How old is the rock? 5. When a sample of lava solidfied, it contained 28g of uranium-238. It that lava sample was later found t...

**Social Studies**

How does a town's economic base determine how the community takes shape? Please help me.

**chemistry**

the answer you did last night was wrong. sorry DrBOb :{

**chemistry**

your all idiots!!! both .09505 and 3.3 are wrong were doing it in a computer program and we reworked the problem!!!

**biology**

oh come on, this is the easiest thing i have ever heard. google much?

**Chemistry**

What volume ( L ) of the solute HCO2H should be combined with 5480 mL of the solvent H2O to make a solution that is 0.443 m HCO2H.

**Chemistry**

Calculate the mass ( kg ) of the solute C4H8O and the volume ( mL ) of the solvent C6H6 that should be combined to generate 6450 g of a solution that is 2.07 m C4H8O. Density (kg/l) C4H8O 0.8892 C6H6 0.8786

**Physics**

Im doing this question right now and I cant understand it! how did you get that value?!

**Literary Analysis and Composition**

LOL K12 in the house baby

**chemistry**

i just submitted it and its nf=2 and balmer

**UCI chemistry**

Its Balmer nf = 2. I just tried it. Dont listen to nf = 1 or 3.

**Social Studies**

Compare and contrast Post-classical feudal systems in Japan and Western Europe, in terms of social classes, gender roles, and rules/laws.

**physics**

For part B: angular momentum = m*r*sqrt(2gh), where r=1.6 and h=2 5*1.6*sqrt(2*9.8*2)

**Chemistry**

So I have that 1.51 V - 1.065 V = .445 V = E and that ΔG = - 10 mol * 96485 J / mol*V * .445 V ΔG = -429358 J so then plugging in: K = e^(-(-429358)/(8.314 J/mol*K * 298 K)) K = 1.82 * 10^75 The 'correct' answer appears to be 1.5 * 10^75 , but that's not...

**Math**

a store owner buys supplies from a vendor for $8,450. the terms of sale are 2/10, n/30. what will the net amount due be if the owner pays the bill by the 10th day after he receives the supplies?

**Algebra**

(x-2)(x-2)= X^2-4x+4 = 1 X^2-4x+3=0 Use quadratic equation and you get X=3,X=1 ALternatively use could take the square of both sides and get x-2=+/- 1 so x=2 +/- 1 so X=3,1

**Physics**

Very close. Remember to change mm to meters. Greatly effects answer. Va/Vb = sqrt[(Tension1/Tension2)*(Diameter2^2/Diameter1^2)] Va/Vb = sqrt[(420/840)*((5.9E-4)^2/(1.3E-3)^2)]

**chemistry**

Why is it more soluble in water?

**chemistry**

its 4

**Chemistry**

It's N2O4. I'm doing the same quiz right now lol.

**Physics**

e no

**CHEM**

Factors which effect reaction rates. 1) Concentration 2) Temperature 3) Presence of a Catalyst 4) Surface area 5) Orientation You store food in a fridge to prevent spoilage. Which factor are you applying to slow the rate of reaction? Which one of the following burns easily and...

**CHEM**

Explain how micelles and more complex solutions work. Consider all Solute-solute, Solvent-solute and Solvent-solvent interactions in such a system.

**CHEM**

In nonpolar molecules what part does Molecular Weight play in the strength on their intermolecular forces?

**CHEM**

Explain in glorious detail the difference between H2O and H2S

**CHEM**

Explain solvation and/or hydration

**CHEM**

Explain why H2O and NH3 are both dipole-dipole interactions yet H2O boils at a significantly higher temperature.

**CHEM**

Explain why H2O and NH3 are both dipole-dipole interactions yet H2O boils at a significantly higher temperature.

**CHEM**

explain 1) Ion-Ion 2) Ion-Dipole 3) Dipole-Dipole 4) Dipole-Induced dipole 5) Induced dipole-Induced dipole

**CHEM**

Distinguish between polar bonds and polar molecules.

**CHEM**

why would ca+ and co+ form soluble salts?

**chemistry**

what is the difference between acid base reaction and oxidation reaction

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