Sunday

February 1, 2015

February 1, 2015

Total # Posts: 76,988

**physics**

A plastic bag is filled with nitrogen at atmospheric pressure and 22.0 oC. Assume that the mass of the bag is negligible and take the temperature of the outside air to be 0 oC. With the help of this "balloon" we want to lift a 50.0 kg girl off her feet. How large a ...
*December 2, 2014*

**Physics**

A catapult on a cliff launches a large round rock towards a ship on the ocean below. The rock leaves the catapult from a height H of 32.0 m above sea level, directed at an angle θ above the horizontal with an unknown speed v0. The projectile remains in flight for 6.00 ...
*December 2, 2014*

**science**

300,000 m away
*December 2, 2014*

**science**

after a rock layer is eroded, whick additional event must occur to create and unconformity, or a gap , in the geologic record
*December 2, 2014*

**Physics**

A proposed space station includes living quarters in a circular ring 50.5 m in diameter. At what angular speed should the ring rotate so the occupants feel that they have the same weight as they do on Earth?
*December 2, 2014*

**Physics**

Two blocks with masses m1 = 1.20 kg and m2 = 2.90 kg are connected by a massless string, as shown in the Figure. They are released from rest. The coefficent of kinetic friction between the upper block and the surface is 0.300. Assume that the pulley has a negligible mass and ...
*December 2, 2014*

**Math**

How to solve for y? x = (3y + 1)/6
*December 2, 2014*

**Physics**

A plastic bag is filled with nitrogen at atmospheric pressure and 22.0 oC. Assume that the mass of the bag is negligible and take the temperature of the outside air to be 0 oC. With the help of this "balloon" we want to lift a 50.0 kg girl off her feet. How large a ...
*December 2, 2014*

**Physics**

A cannon barrel is elevated at an angle of 45°. It fires a ball with a speed of 250 m/s. (For the following questions, ignore air resistance.) (a) What height does the ball reach? m (b) How long is the ball in the air? s (c) What is the horizontal range of the cannon? kmp
*December 2, 2014*

**chemistry**

does any solid pbcl2 form when 3.5mgNacl is dissolved in 0.250L of 0.12M of lead nitrate?
*December 2, 2014*

**Alg1**

I will not try to figure out where the student went wrong, but rather just do it the right way: 4√50 - 2√8 = 4(√25)(√2) - 2(√4)(√2) = 4(5)√2 - 2(2)√2 = 20√2 - 4√2 = 16√2
*December 2, 2014*

**Math**

To make an international telephone call , you need the code for the country you are calling . The codes for country A,B and C are three consecutive integers whose sum is 105. Find the code for each country .
*December 2, 2014*

**Science Please Help**

Which of the following is a testable hypothesis? A. Altered temperature may affect gas production, which measures fermentation rate. B. Does temperature affect fermentation? C. Temperature decreases will affect gas production and fermentation much of the time. D. If ...
*December 2, 2014*

**Science Please Help**

Which of the following is a testable hypothesis? A. Altered temperature may affect gas production, which measures fermentation rate. B. Does temperature affect fermentation? C. Temperature decreases will affect gas production and fermentation much of the time. D. If ...
*December 2, 2014*

**3rd grade math**

What is the next number pattern below? 16,24,32,40,48
*December 2, 2014*

**Chemistry**

It takes 476 kJ to remove 1 mole of electrons from the atoms at the surface of a solid metal. how much energy (in kJ) does it take ti remove a single electron from an atom at the surface of this solid metal?
*December 2, 2014*

**Chemistry**

A student weighs out 15g of the hydrated salt KCl (this is KCl and water) and heats it till a constant mass of 12 grams remains. What percent of the salt was water?
*December 1, 2014*

**Math Proof**

Prove f(x)=b^x is continuous on (-infinity,infinity) i.e. a exist in the reals. here assume b does not equal 1, but b>0
*December 1, 2014*

**Physics**

A plastic bag is filled with nitrogen at atmospheric pressure and 22.0 oC. Assume that the mass of the bag is negligible and take the temperature of the outside air to be 0 oC. With the help of this "balloon" we want to lift a 50.0 kg girl off her feet. How large a ...
*December 1, 2014*

**American History**

1. Reagan embraced the idea that through tax incentives the private sector would shift its resources from tax shelters to productive investment. This theory is referred to as A. supply-and-demand economics. B. neofederalism. C. deficit economics. D. supply-side economics. 2. ...
*December 1, 2014*

**Calculus**

Differentiate. e^cos(x^2+1) Is the answer -2xe^cos(x^2+1) sin(x^2+1)?
*December 1, 2014*

**Math**

A game is played by throwing darts at a target. A player can choose to throw two or three darts. Darcy plays two games. In Game 1, he chooses to throw two darts, and wins if he hits the target at least once. In Game 2, he chooses to throw three darts, and wins if he hits the ...
*December 1, 2014*

**Chemistry**

This helped a lot! Thank you. The following are my answers and reasons. A. False because n=3 has energy so only need to add a bit. N=1 or ground state requires more energy to ionize because it is smaller (the beginning) B. True because the electron that occupies the first she...
*December 1, 2014*

**Chemistry**

An electron is excited from the n=1 ground state to the n=3 state in a hydrogen atom. Which of the following statements are true? Correct the false statements to make them true. A. It takes more energy to ionize (completely remove) the electron from n=3 than from the ground ...
*December 1, 2014*

**Math**

A cube has a surface area of 6534 square feet. What is its volume?
*December 1, 2014*

**General Calculus Question**

On a graph what ways can it not be differentiable? I know at cusps it's not differentiable but are there other instances where it is not differentiable?
*December 1, 2014*

**History Day**

I was wondering if anyone knows what the least commonly done projject for History Day is?
*December 1, 2014*

**sci**

can we predict when a hurricane comes. how
*December 1, 2014*

**PLEASE HELP CHEMISTRY**

CuSO4.xH2O Determine the percent by mass of water in your sample of hydrated copper (II) sulfate. Show your calculations clearly. My work. i got 10% is that correct
*December 1, 2014*

**help**

this is for a project
*December 1, 2014*

**help**

please someone help im sorry for bothering
*December 1, 2014*

**help**

can we predict when a hurricane will occur
*December 1, 2014*

**pretty algebra**

A commuter train pulling 8 cars had room for another 84 passengers. Halfway...
*December 1, 2014*

**math**

A recipe for a home-made disinfectant calls for adding one-half cup of clorox to one gallon of water. Mrs. Jenkins wants to make this solution in a 32-ounce spray bottle. How many fluid ounces of clorox should be added to 32 fluid ounces of water to have the same clorox-to-...
*December 1, 2014*

**Algebra**

Thankyou
*December 1, 2014*

**ethics**

Which of the following answers to the meaning of life did Tolstoy hold prior to his change of heart and mind?
*December 1, 2014*

**science**

A jellyfish can propel itself with jets of water pushed out of its bell, a flexible structure on top of its body. The elastic bell and the water it contains function as a mass-spring system, greatly increasing efficiency. Normally, the jellyfish emits one jet right after the ...
*December 1, 2014*

**chemistry**

Thomson example could be - dialysis and the diffusion of gases??
*December 1, 2014*

**chemistry**

dalton- example and picture solid foothold as a fundamental chemical object; fundamented the atomic theory so what would be a pic and ex of his and could that be a contribution
*December 1, 2014*

**chemistry**

Democritus- example and picture is it an atom and a picture of a atoms that she wants?? Did he rely on experimental evidence to justify his ideas? yes he gave an image of an atom that distinguished them from each other by their shape, size, and the arrangement of their parts
*December 1, 2014*

**physics**

2. You push a 2.0 Kg block against a horizontal spring (the spring constant is k=200 N/m) compressing it by 15 cm. Then you release the block and the spring sends it sliding across a tabletop. The block stops 75 cm from where you released it. (a) Find the work done by the ...
*December 1, 2014*

**algebra 2**

x^2-18x-40=0
*December 1, 2014*

**algebra 2**

Solve for x. 250= (13+x)^2
*December 1, 2014*

**French**

How do I say I'm in high school in French? Je suis en lycée?
*December 1, 2014*

**Chemistry**

a gas phase compound has a density of 2.10 g/l at 751 torr and 100 c what is the molecular weight
*December 1, 2014*

**physics**

A rock is thrown downward into a well that is 8.58 m deep. If the splash is heard 1.08 seconds later, what was the initial speed of the rock?
*December 1, 2014*

**Math**

csc ( x ) = 1 / sin ( x ) sin ( x ) = 1 / 7 csc ( x ) = 1 / ( 1 / 7 ) = 7 cot ( x ) = 1 / tan ( x ) tan ( x ) = 2 / 3 cot ( x ) = 1 / ( 2 / 3 ) = 3 / 2
*December 1, 2014*

**Calculus**

Which of the following functions does not have a derivative of zero? A. y=-1/100 B. y=4(pi)^2-9 C. y=sin^2x+cos^2x D. y=cscxtanxcosx E. All do
*December 1, 2014*

**AP Biology**

The respiration of plants is a biochemical reaction and should have a rate determined by the Arrhenius equation, k = Ae-EA/RT. Here, k is the rate, A is a constant, EA is the activation energy for the reaction, R is the gas constant, and T is the temperature in kelvins. If the...
*December 1, 2014*

**science**

An electron of mass 9.11 × 10-31 kg and charge 1.6 × 10-19 C passes through a cathode ray tube with a velocity of 3.7 × 107 m/s. It enters a magnetic field of flux density 0.47 mT at a right angle. What is the radius of curvature of the path in the magnetic ...
*December 1, 2014*

**famu**

Construct a 99% confidence interval for the population mean, ì. Assume the population has a normal distribution. A group of 19 randomly selected employees has a mean age of 22.4 years with a standard deviation of 3.8 years. Round to the nearest tenth.
*December 1, 2014*

**band essay-Ms. Sue**

Thanks for the suggetions and feedback!
*December 1, 2014*

**band essay-Ms. Sue**

Who wouldn’t want the chance to go to Puerto Rico? I have been excited for this band trip opportunity since it was introduced last winter. A once in a lifetime opportunity to share my love of music and explore another culture is an eyeopening experience! I believe I am a ...
*December 1, 2014*

**chemical equations**

The roman numeral confuses me and I don't know what some of the formulas are-once I have the equaiton I can balance it. So I guess my problem is getting to the equation
*December 1, 2014*

**chemical equations**

I need help figuring out how to write these chemical reactions into chemical equations Copper(II)oxide + hydrochloric acid -> copper(II)chloride + water CuO2+ HCl -> CuCl + H2O? Aluminum + copper(II) chloride-> copper + aluminum chloride Al+CuCl -> Cu + AlCl ...
*December 1, 2014*

**chemical equations**

How do I write the chemical equation for Copper(II)nitrate + sodium hydroxide -> Copper(II)hydroxide + sodium nitrate? CuNO3 + NaOH-> CuOH + Na(NO3) is that right? Copper(II)hydroxide -> Copper(II)oxide + water CuOH -> CuO + H2O?
*November 30, 2014*

**trig**

Two circles of radii 5 and 3 cm, respectively, intersect at two points. At either point of intersection, the tangent lines to the circles form a 60◦ angle, as in Figure 2.2.4 above. Find the distance between the centers of the circles
*November 30, 2014*

**Calculus**

Find the limit as x approaches 1 5/(x-1)^2 I don't understand how to solve it because there would be a 0 on the denominator.
*November 30, 2014*

**Chemistry**

This was actually helpful, thank you!
*November 30, 2014*

**Chemistry**

5.) Which of the following is the strongest oxidizing agent? a.) Zn(s) b.) Mg(s) c.) Al3+(aq) d.) Mg2+(aq)
*November 30, 2014*

**chemistry-chemical equations**

thank you :)
*November 30, 2014*

**chemistry-chemical equations**

How do I write the balanced chemical equation for Copper +nitric acid -> copper(II)nitrate+ nitrogen dioxide + water
*November 30, 2014*

**band essay? can you read it?**

This band scholarship would help me immensely to be able to accomplish my goal of going on the trip to Puerto Rico this Spring Break. I am a good candidate for this band scholarship because along the lines of what Mr. Schmitz has said, in order for me to help you, you have to ...
*November 30, 2014*

**band essay?**

thanks, I will proofread and check for errors :)
*November 30, 2014*

**band essay?**

I have to write an essay on why I deserve a scholarship for our band class trip to Puerto Rico, I was wondering what English teachers would be looking at/for in this essay and how long it should roughly be
*November 30, 2014*

**Chemistry**

it is for any chemical reaction, there is not a specific one as long as the video explained what the reactant(s) and the product(s) were then it would work.
*November 30, 2014*

**Chemistry**

I'm looking for a video of a chemical reaction that can help me answer these questions What are the names of the reactants and products and their states @ room temperature? What type of reaction is it?
*November 30, 2014*

**ApWorld history**

Okay thank you so much
*November 30, 2014*

**ApWorld history **

How did religion stay the same throughout the spread of islam in west Africa in circa 800 C.E. and circa 1750
*November 30, 2014*

**Calculus**

Find limit as x approaches 5 (x^2-3x-10)/(x-5)
*November 30, 2014*

**Calculus**

Find limit as x approaches -1 (x^2+2x+3)/(x^2+1) A. 0 B. 1 C. Infinity D. DNE E. None of these
*November 30, 2014*

**ApWorld history**

Thank you
*November 30, 2014*

**ApWorld history **

Would Arabic becoming an important language count as a change to the spread of islam in a ccot essay
*November 30, 2014*

**physics**

How much heat (in kJ) will it take to bring 56 kg of ice at -8°C to dry steam? Answer to 3 significant figures
*November 30, 2014*

**science**

what is pollution
*November 30, 2014*

**math**

Sean has 8-inch pieces of toy train track and Ruth has 18-inches of train track. How many of each piece would each child need to build tracks that are equal in length?
*November 30, 2014*

**Calculus**

Find the derivative: f(x)=1/cubed root(3-x^3) A. -1/3(3-x^3)^4/3 B. x^2/(3-x^3)^4/3 C. -x^2/(3-x^3)^2/3 D. -x^2/(3-x^3)^4/3 E. None of these
*November 30, 2014*

**Calculus**

Find the limit as x approaches 0 [(sqrt(x+9))-3]/x A. 0 B. 1 C. Infinity D. 1/3 E. None of these
*November 30, 2014*

**Calculus**

Find the derivative of x^2f(x) A. x[xf'(x)+2f(x)] B. 2xf'(x) C. x[xf'(x) +2f'(x)] D. x^2f'(x) E. None of these
*November 30, 2014*

**Calculus**

Find an equation of the tangent line to the graph of x^2+3y^2=4 at the point (1,1) A. y+1=-1/3(x+1) B. y-1=-x/3y(x-1) C. x+3y=2 D. y-1=-1/3(x-1) E. None of these
*November 30, 2014*

**Calculus**

Find the equation of the line that passes through (1,3) and is perpendicular to the line 2x+3y+5=0 A. 3x-2y+3=0 B. 2x+3y-11=0 C. 2x+3y-9=0 D. 3x-2y-7=0 E. None of these I got E?
*November 30, 2014*

**math**

Find the height of a ball after 3 seconds, if the ball is hit with an initial velocity of 90 feet per second at an angle of 60 degrees from an initial height of 5 feet.
*November 30, 2014*

**pre-cal**

Find the height of a ball after 3 seconds, if the ball is hit with an initial velocity of 90 feet per second at an angle of 60 degrees from an initial height of 5 feet.
*November 30, 2014*

**English**

How to find a keywords of the quote our deepest fear
*November 30, 2014*

**Calculus**

If f(1)=4 and f'(1)=2, find an equation of the tangent line at x=1 A. y=2x+2 B. y=2x-2 C. y=4x-7 D. y=4x-2 E. None of these
*November 30, 2014*

**Calculus**

Find f'(x) if f(x)=sin^3(4x) A. 4cos^3(4x) B. 3sin^2(4x)cos(4x) C. cos^3(4x) D. 12sin^2(4x)cos(4x) E. None of these I got D using the chain rule?
*November 30, 2014*

**Calculus**

Find d^2y/dx^2 for y=(x+3)/(x-1) A. 0 B. y=-8/(x-1)3 C. y=-4/(x-1)^3 D. y=8/(x-1)^3 E. None of these I got a positive number but am not sure about the denominator in the second derivative.
*November 30, 2014*

**Calculus**

Find dy/dx for y=sin(x+y) A. 0 B. (cos(x+y))/(1-cos(x+y) C. cos(x+y) D. 1 E. None of these I know I'm supposed to use implicit differentiation but I'm not sure how to go about it with sin
*November 30, 2014*

**Calculus**

Find an equation of the tangent line to the graph of f(x)=xsinx when x=0. A. y=0 B. f'(x)=0 C. y=xcosx+sinx D. y=x E. None of these
*November 30, 2014*

**Calculus**

For which of these functions f(x) does limit as x approaches negative infinity f(x)=2 A. (x-2)/(3x-5) B. 2x/sqrt(x-2) C. (2x^2-6x+1)/(1+x^2) D. (2x-1)/(x^2+1) E. None of these
*November 30, 2014*

**Calculus**

Find limit as x approaches 5 (x^2-3x-10)/(x-5) A. 2 B. DNE C. 0 D. 7 E. None of these
*November 30, 2014*

**Calculus**

Sorry, somehow this repeated
*November 30, 2014*

**Calculus**

If f(x) = {x^2+3x-1, x<=2 and -3bx+3, x<2 , find the value of b in order for f to be continuous
*November 30, 2014*

**Calculus**

If f(x) = {x^2+3x-1, x<=2 and -3bx+3, x<2 , find the value of b in order for f to be continuous
*November 30, 2014*

**Calculus**

If f(x)=sin(2x), find f"(x) A. 2cos(2x) B. -4sin(2x) C. -2sin(2x) D. -4sinx E. None of these Is it B from using chain rules?
*November 30, 2014*

**Calculus**

Find the derivative for f(x)=-x^2+x Do I put the -x^2 as a denominator? How would I solve it if that's what I'm supposed to do?
*November 30, 2014*

**Calculus **

Find limit as x approaches -1 (x^2+2x+3)/(x^2+1) A. 0 B. 1 C. Infinity D. DNE E. None of these
*November 30, 2014*

**Calulus**

Find f'(x): f(x)=(x^2-3x)/x^2 A. 2x-3/x^2 B. 2x-3/2x C. 1-(3/x) D. 3/x^2 E. None of these I can put it into the division rule for the derivative but get confused when I'm simplifying.
*November 30, 2014*

**Math**

A game is played by throwing darts at a target. A player can choose to throw two or three darts. Darcy plays two games. In Game 1, he chooses to throw two darts, and wins if he hits the target at least once. In Game 2, he chooses to throw three darts, and wins if he hits the ...
*November 30, 2014*

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