# Posts by Sarah

Total # Posts: 5,805

AP Chemistry
Can anyone explain how to find potential of the cell?

Chem
Thank you Just one more question Why is it (63.55/2) g Cu ?

Chem
Can someone please explain how to tackle this problem? Cu - Anode electrode Zn - Cathode electrode A current of 2 amps is sustained for 16 minutes. what mass of Cu(s) is deposited on the zinc electrode? (Faradays' constant: 96500 C/mol e-)

chem
(sorry - accidentally posted it as physics problem) Can someone please explain how to tackle this problem? Cu - Anode electrode Zn - Cathode electrode A current of 2 amps is sustained for 16 minutes. what mass of Cu(s) is deposited on the zinc electrode? (Faradays' ...

Physics
Can someone please explain how to tackle this problem? Cu - Anode electrode Zn - Cathode electrode A current of 2 amps is sustained for 16 minutes. what mass of Cu(s) is deposited on the zinc electrode? (Faradays' constant: 96500 C/mol e-) Please and thank you!!

Probability and statistic
Suppose X has an exponential distribution with mean equal to 13. Determine the following: (a) Upper P left-parenthesis x ⁢ greater-than 10 right-parenthesis (Round your answer to 3 decimal places.) (b) Upper P left-parenthesis x ⁢ greater-than 20 right-parenthesis...

probability and statistic
Suppose that the number of asbestos particles in a sample of 1 squared centimeter of dust is a Poisson random variable with a mean of 1000. What is the probability that 10 squared centimeters of dust contains more than 10090 particles? Round your answer to 3 decimal places.

Calculus
Yeah That's where I was confused.Probably. Thank you!

Calculus
Okay thanks! I have drawn my graph like that!

Calculus
Wait the Points are (-1,0) (0,0) and (1,0). Im confused since the critical points and these points are both at x=-1, x=1

Calculus
Yes, I was confused why x=-1 and x=1 had two different points. Maybe it's a typo?

Calculus
Sketch the graph of the function that has the following properties. f is continuous on (-infinity, infinity). points: (-1,2), (0, 0), (-1,0) f'(x)>0 at (-infinity, -1) f'(-1)=0 f'(x)<0 at (-1, 1) f'(1)=0 f'(x)>0 on (1, infinity) f"(x)<0 on...

Calculus
A printed page is to have 1.5 inches margin on all sides. The page should contain 144 square inches of type. What dimension of the page will minimize the area while still meeting these other requirements?

calc
Find the volume of the solid generated by revolving the region bounded by y=e^(5/2x),y=0,x=1, and x=5 about the x-axis.

calc
Find the volume of the solid generated by revolving the given region in the 1st quadrant about the y-axis: y=10x^2,x=0,y=810.

calculus
Find the volume generated by revolving about the x-axis the region bounded by the following curves y=sqrt/(4x+3),x=0,x=4, and y=0. (Use "pi" for π).

CALC
Find the volume of the solid obtained by revolving the region bounded by y=(19/3)x-(19/3)x^2 and the x-axis around the x-axis. Keep answer in terms of pi PLease explain each step

Probability and statistic
The time until recharge for a battery in a laptop computer under common conditions is normally distributed with mean of 270 minutes and a standard deviation of 50 minutes. a) What is the probability that a battery lasts more than four hours? Entry field with incorrect answer (...

CALC
my equation was y=900+C/e^(1/150)t

CALC
A 200-gallon tank is currently half full of water that contains 50 pounds of salt. A solution containing 1 pounds of salt per gallon enters the tank at a rate of 6 gallons per minute, and the well-stirred mixture is withdrawn from the tank at a rate of 6 gallons per minute. ...

Probability and statistics
Astronomers treat the number of stars in a given volume of space as a Poisson random variable. The density in the Milky Way Galaxy in the vicinity of our solar system is 1 star per 16 cubic light years. (a) What is the probability of 3 or more stars in 16 cubic light years? (b...

probability and statistic
Heart failure is due to either natural occurrences (85%) or outside factors (15%). Outside factors are related to induced substances or foreign objects. Natural occurrences are caused by arterial blockage, disease, and infection. Assume that causes of heart failure between ...

math
If you will triple the three it is called thrice but when you four what is it

Chemistry
Is NH4+ polar or non polar?

chemistry
Is NH4+ po;ar or non polar?

CALC
the exponent is (y-x^2)

CALC
Find the particular solution of the given differential equation dydx=−4xe(y−x^2);y=11whenx=1. THanks

CALCULUS
Yes but I'm not sure what the m>0 is for

CALCULUS
Let y(t) denote the mass of a radioactive substance at time t.t. Suppose this substance obeys the equation y′(t)=−14y(t). Assume that, initially, the mass of the substance is y(0)=M>0. At what time does half of the mass remain? (Round your answer to 3 decimal ...

Suppose that y′=ky, y(0)=7, and y′(0)=4. What is y as a function of t ? PLEASE EXPLAIN

CALCULUS

CALC

Calculus
to make it continuous f(2)=a so it would equal -1?

Calculus
So a=-1 That makes sense because it's continuous

Calculus
find the value of a, if it exists, such that the following function is continuous at X = 2. piecewise function f(x)={x^2-3x+1, if x>2; a, if x=2; 3-2x, if x<2 I found the limits from left and right of 2 = -1 so the limit exists but I don't know how to figure out a

Math
Among a group of people, 10% are from NYC and 90% are not. All people from NYC are under 18 years old, and 70% of those not from NYC are also under 18 years old. One person is chosen at random, and he or she is under 18. What is the probability that the person chosen is from ...

CALCULUS
Find the derivative of y=4sinx−2cosx

How long will it take for an investment to double at 7% p.a compounded monthly?

Calc
Find the derivative of y=4sinx−2cosx

Calculus
let f(x)=2x-7. Use the rigorous definition of limit to show that lim x-->4 f(x)=1

English
Can you summarize this case study 300 words minimum? Overview Hospital A: Porter Regional Medical Center (PRMC) Located on the east side of town, Porter Regional Medical Center (PRMC) was a for-profit hospital, consisting of 110 hospital beds, 8 of which were reserved for ...

geography
Under the Soviet system, the government a. controlled all forms of communication. b. allowed newspapers to print whatever they wanted. c. controlled editorials but not the reporting of news. d. encouraged access to a wide variety of news sources.

math
Find each value if cos A=12/13 with 0 (degrees) <= A <= 90 (degrees) and if sin B=8/17 with 90 (degrees) <= B <=180 (degrees) 1. sin(A+B) 2. cos(A-B) 3. tan(A-B)

Teachers aide
What are two types of wheelchairs used by the physically challenged students are the ?I think the two would be a orthosis and the power driven

Geometry
31.Identify the Hypothesis of the statement below. If you are riding on a train, then it will stop at every station on the line. A.You are riding on a train B.It will stop at every station on the line C.You are not riding on a train D.It will not stop at every station on the ...

Math
15 blocks

math plz help my last chance to do this homework
how do you post a pic

math plz help my last chance to do this homework
a) write an expression in simplest form for the perimeter of each triangle. b)write another expression in simplest form that shows the difference between the perimeter of the larger triangle and the perimeter of the smaller triangle.

Algebra
i think a is right

Algebra
Randall wants to mix 41 lb of nuts worth ​$2 per lb with some nuts worth ​$8 per lb to make a mixture worth ​$7 per lb. How many pounds of ​$8 nuts must he​ use? Pounds of nuts-cost per pound-total cost 41-$2-? x-$8-? ?-$7-? There is a chart and I... Algebra A chemist wishes to mix a solution that is 4​% acid. She has on hand 66 liters of a 2​% acid solution and wishes to add some 8​% acid solution to obtain the desired 4​% acid solution. How much 8​% acid solution should she​ add? There is a ... Algebra The height of Tower A is 940 feet more than Tower B. The two towers have a combined height of 1,540 feet. What are the heights of each​ tower? BOB PURSLEY PLEASE HELP What is the electrostatic force between one object with a charge of +5.0 × 10−6 C, and a second object with a charge of +2.0 × 10−6 C? The objects are 1.2 meters apart. In a pith ball experiment, the two pith balls are at rest. The magnitude of the ... URGENT HELP 1.In a pith ball experiment, the two pith balls are at rest. The magnitude of the tension in each string is |T| = 0.55 N, and the angle between each string and a vertical line is θ = 27.33°. What are the values for the magnitudes of electrostatic force, Fq, and the ... Physics @bobpursley Physics One object has a charge of +5.0 × 10−6 C, and a second object has a charge of +2.0 × 10−6 C. The objects are 0.5 meters apart. What is the electrostatic force between them? College Algebra Pounds of nuts-cost per pound-total cost 41-$2-? x-$8-? ?-$7-? There is a chart and I have to fill in the question marks. x= 205/6 0r 34.16667

College Algebra
Randall wants to mix 41 lb of nuts worth ​$2 per lb with some nuts worth ​$8 per lb to make a mixture worth ​$7 per lb. How many pounds of ​$8 nuts must he​ use?

Chemistry
Calculate H2 Equation 1- CH4g+2O2g+CO2g+2H2OgH1=-890kj Equation 2- CH4g+O2g+CH2Og+H2OgH2=? Equation 3- CH2Og++O2g+CO2g+H20gH3=-518kj

Chemistry
Equation 1- 2Ss+3O2g+2SO3gh1=? Equation 2- 2Ss+2O2g+2SO2gh3=-594kj Equation 3- 2SO2g+O2g+2SO3gh3=-198kj Use Hess's law in your own words.

Chemistry
Consider this reaction N2g+O2g+2NOg H=180.5kj How much heat would be required to produce 1.300 mol NOg?

Chemistry
The reaction of 1 Mol of iron metal with 3 Mol aqueous HCI produces 1.5 mol H2 gas, 1 mol aqueous FeCI3, and 87.9 kj of heat. Write a thermochemical equation for this reaction

ELA
Yeah I get what your saying but I need a to write 2 or 3 paragraph a about what I want to know.. And I want to know the same thing you do but I don't know how to write that in a paragraph explaining!!

ELA
What are few questions and stuff that people or anyone would want to know about electrical engineering.... I need help writing 3 paragraphs based on that.

Chemistry
Calculate the number of moles of solute in each of the following solutions: Solution Moles of Solute 2.1 L of 0.21 M NH4HCO3 3.5 L of 0.28 M MgCO3

English p3
Traditional healers should be allowed to practice and prescribe medicines in hospitals and clinics and i agree with this topic. Speech should be in one page.

English
Speech about traditional healers should be allowed to practice and prescribe medicines in hospitals and clinics and I agree with this topic.

Engineering
What are few things that people want to know about electrical engineering??

Journalism
Anyone.. I am not really sure

Journalism
List the things that people actually want to know about electrical engineering

life orientation
People should stop engaging in fraud. it is not the only way to make a living. Being engaged in fraud will end you up on jail. You would loose momemts you would have with family

Journalism
What site

Journalism
I need 15 questions to ask an electrical engineer.

History essay
How to write a history essay based on a question with prompts?

Math
That's the issue I am having

Math
Find all of the solutions for this addition problem. Each different letter in the puzzle stands for a different digit. Letters that are the same stand for the same digit. Remember to include all of the criteria from the guidelines. ONE + ONE = TWO

math
seven horses are entered in a race. If two horses are tied for first​ place, and there are no ties among the other five ​horses, in how many ways can the seven horses cross the finish​ line?

math
horses are entered in a race. If two horses are tied for first​ place, and there are no ties among the other five ​horses, in how many ways can the seven horses cross the finish​ line?

Geograph
I need help writing a paragraph of why the stamp act of 1765 was not fair to the colonist.

Geography
Oops wrong one

Geography
The Stamp Act of 1765 was the first internal tax levied directly on American colonists by the British government. The act which imposed a tax on all paper documents in the colonies came at a a time when the British empire was deep in debt from the seven years war and looking ...

george mason
horses are entered in a race. If two horses are tied for first​ place, and there are no ties among the other five ​horses, in how many ways can the seven horses cross the finish​ line?

mason
seven horses are entered in a race. If two horses are tied for first​ place, and there are no ties among the other five ​horses, in how many ways can the seven horses cross the finish​ line?

Language Arts
Which of the following passages from the novel best illustrates the most extreme hostility between the Chinese and American communities in San Francisco?

geography
How coal is formed?

precalculus
solve log(2+x)-log(x-3)=log2 I know the answer is 8

math
solve log(2+x)-log(x-3)=log2

English (research)
How can I prove that a superhero is a monster? i.e. - Spider-man

Data analysis
hello hi did you figure out how to do this? ahahha help

Math
Find the rotation in revolutions per minute given the angular speed and the radius given the linear speed and the rate of rotation. 1. w= 2.7 rad/s 2. v=24.8 m/s, 120 rev/min 3. w= 4/3Pi rad/hr Please help me with these problems! I am a visual learner and I learn best when ...

Math

Math
Meredith's new scale measures in both pounds and kilograms. The information on the box says the scale has a weight limit of 200 kilograms or 440 pounds. Using this information, approximate the unit rates of kilograms per pound and pounds per kilogram, to the nearest ...

economics
yes

Math/ELA
What can I do now as a 7th grader to prepare and save for college

Chem
Consider the following balanced equation: 2N2H4(g)+N2O4(g)→3N2(g)+4H2O(g) Complete the following table showing the appropriate number of moles of reactants and products. If the number of moles of a reactant is provided, fill in the required amount of the other reactant, ...

Calculus
two small planes take off from the same airport at the same time. One travels north at 200 km/h, and the other, west at 150 km/h. If the planes fly at the same altitude, how fast are they separating after 2 hours?

organic chemistry
Apart from the fact that between the two structures, only cyclohexe-4-ene-cis-1,2-dicarboxylic acid has the OH group shown on the IR spectrum. In what other majors way will the IR spectrum of cyclohex-4-ene-cis-1,2-dicorboxylic anhydride differ from the IR spectrum of ...

The bases of trapezoid $ABCD$ are $\overline{AB}$ and $\overline{CD}$. We are given that $CD = 8$, $AD = BC = 7$, and $BD = 9$. Find the area of the trapezoid.