Saturday
May 28, 2016

Posts by Erica

Total # Posts: 579

Math
The population of humorville is 8,500 people. In this town, jokes travel fast. In one hour, each person who hears a joke tells three other people who have not heard it, and tells no one else. Last Friday, a visitor from out of town told the police chief a new joke at 10:00a.m...
March 19, 2012

Statistics
Suppose that people's heights (in centimeters) are normally distributed, with a mean of 165 and a standard deviation of 6. We find the heights of 100 people. (a) How many would you expect to be between 157 and 173 cm tall? (b) How many would you expect to be taller than ...
March 14, 2012

Math
thanks steve
March 13, 2012

Math
I snap my fingers now. in one second, i snap them again. I wait two seconds and snap them a third time. I wait four seconds before snapping them again. then i wait eight seconds, then sixteen, and the pattern continues on. the interval between snaps doubles each time How many ...
March 13, 2012

Chemistry
2NaOH+2Al+2H2O --> 2NaAlO2+3H2 here is the reaction. If i am trying to find the mass of hydrogen produced and i am trying to convert .95 moles Al to moles H, which number from the reaction do I use for H when converting from moles to moles? Do I 6 because that's the ...
March 9, 2012

Math
the design below grows each day, as shown. if the pattern continues to grow like this, how many tiles will there be in the design on the tenth day? on the fiftieth day? Day 1 1 tile Day 2 5 tiles Day 3 13 tiles
March 5, 2012

Algebra 2
On some tubes of caulking, the diameter of the circular nozzle opening can be adjusted to produce lines of varying thickness. The table shows the length l of caulking obtained from a tube when the nozzle opening has diameter d and cross-sectional area A. 48. Determine whether ...
March 3, 2012

math
Mr. Jaskson's lunch cost $8.00 plus 8% sales tax. He tipped the server 15% of total bill after sales tax was added. How much did Mr. Jackson spend in all?
February 26, 2012

chemistry
BrO^3- + 3Sb^3+ + 6H^+ -----> Br^- + 3Sb^5+ +3H2o
February 24, 2012

Physics
well that doesn't look readable. the answer should still be right but I'll rewrite how I did the math Cfs = mv^2/rFn = ((2πr/T)^2)/r(g) = (4(π^2)r)/g(T^2) Cfs = 4(π^2)(0.159 m) / (9.8 m/s^2)(1.50 s)^2 = 0.28467
February 20, 2012

Physics
Static Friction Coefficient = Cfs For of Static Friction = Fs Normal Force = Fn Centripetal Force = Fc mass = m radius = r speed = v period of time = T Fs = Cfs * Fn so Cfs = Fs/Fn Fc = Fs and since Fs = mv^2/r Cfs = Fs/Fn = mv^2/r*Fn v = 2πr/T and Fn = mg so.... mv^2 (2...
February 20, 2012

Probability
In a Cc x Cc crossing of peas, 5 offspring are of genotype CC, 12 are of genotype Cc, and 6 are of genotype cc. What is the probability of this event?
February 16, 2012

Chemistry
How many formula units of (NH4)3PO4 are present in 12.25 g of K3PO4? Please explain so I can do these in the future! Very confused.
February 15, 2012

Chemistry
So the answer is 4.88?
February 15, 2012

Chemistry
If 2.44 moles of H2 are reacted with excess Cl2, how many moles of Hcl can be produced? Please explain.
February 15, 2012

Physics
Ultrasound with a frequency of 4.275 MHz can be used to produce images of the human body. If the speed of sound in the body is the same(1.79 km/s) as in salt water, what is the wavelength in the body?
February 6, 2012

algebra
-13^2-4(-13)(36) That answer squared
February 6, 2012

English
What kind of clause would (when painters looked at rapidly moving horses.) would it be a adverb,adjective, or noun?
February 6, 2012

Physics
A car's initial velocity of 13.5 m/s accelerates at a rate of 1.9 m/s^2 for 6.2 s. Then, it accelerates at a rate of -1.2 m/s^2 until it stops. 1) What is the car's maximum speed? 2) What is the total time from the start of the first acceleration until the car is ...
February 1, 2012

Physics
A car is speeding at 33.4 m/s. A police car starts in pursuit from rest when the car is 100 m past the cruiser. At what rate must the cruiser accelerate to catch the speeder before the state line, 1.2 km away from the speeding car? Include all steps if possible please, so that...
February 1, 2012

English- Infinitive phrases
That website is very helpful! Thank you :) So, because there is no "to" would the infinitive phrase include the verb too? : "made him work hard"
January 29, 2012

English- Infinitive phrases
For this question, the directions say to name the TWO infinitive phrases in this sentence... His wish to succeed as an architect made him work hard. I know that "to succeed as an architect" would be one infinitive phrase, but there isn't another "to" ? ...
January 29, 2012

Probability
Assume that 20% of a very common insect species in your study area is parasitized. Assume that insects are parasitized independently of each other. If you collect 10 specimens of this species, what is the probability that no more than 2 specimens in your sample are parasitized...
January 27, 2012

Probability
A drug company claims that a new headache drug will bring instant relief in 90% of all cases. If a person is treated with a placebo, there is a 20% chance that the person will feel instant relief. In a clinical trial, half the subjects are treated with the new drug and the ...
January 27, 2012

Probability
A drawer contains six bags numbered 1-6, respectively. Bag i contains i blue balls and 2 green balls. You roll a fair die and then pick a ball out of the bag with the number shown on the die. What is the probability that the ball is blue? Thank you!
January 27, 2012

Probability
A screening test for a disease shows a positive test result in 95% of all cases when the disease is actually present and in 20% of all cases when it is not. When the test was administered to a large number of people, 21.5% of the results were positive. What is the prevalence ...
January 27, 2012

Probability
You toss a fair coin four times. Find the probability of no more than three heads given that at least one toss resulted in heads. Thank you very much!!
January 27, 2012

Geometry
The ratio of the side lengths of a triangle. Is 2:4:5 and the perimeter is 55 cm. What is the length of the shortest side?
January 25, 2012

Chemistry
would you multiple 500x0.20 and then divide the amount with 1.30
January 20, 2012

Chemistry
large dose of vitamin C are supposed to cure the common cold. One commercial over-the-counter product consists of 500-mg tablets that are 20% by weight vitamin C. How many tablets should one take for a 1.30g dose of vitamin C?
January 20, 2012

chemistry
As the temperature of a gaseous substance is decreased at constant pressure, it will undergo a series of physical changes. Which is the correct sequence of physical states that will be encountered? a.Liquid, solid, gas b.Gas, solid, liquid c.Solid, liquid, gas d.Gas, liquid, ...
January 20, 2012

chemistry
As the temperature of a gaseous substance is decreased at constant pressure, it will undergo a series of physical changes. Which is the correct sequence of physical states that will be encountered?
January 20, 2012

History
Discuss why England's North American colonial empire had outstripped those of her European rivals by the end of the seventeenth century?
January 18, 2012

Probability
Assume that P(A) = 0.4, P(B) = 0.4, and P(A∪B) = 0.7. Find P(A∩B) and P(A complement ∩ B complement).
January 17, 2012

Probability
In the game of poker, determine the number of ways a straight (five cards with consecutive values, such as A 2 3 4 5 or 7 8 9 10 J or 10 J Q K A, but not all of the same suit) can be picked.
January 17, 2012

Probability
Twelve children are divided up into three groups, of five, four, and three children, respectively. In how many ways can this be done if the order within each group is not important? Thank you so much!
January 17, 2012

Probability
Automated chemical synthesis of DNA has made it possible to custom-order moderate length DNA sequences from commercial suppliers. Assume that a single nucleotide weighs about 5.6 X 10^-22 grams and that there are four kinds of nucleotides. If you wish to order all possible DNA...
January 16, 2012

Algebra 2
From 1990 to 1994, the mail order sales of health products in the United States can be modeled by S = 10t 3 + 115t 2 + 25t + 2505 where S is the sales (in millions of dollars) and t is the number of years since 1990. In what year were about $3885 million of health products ...
December 30, 2011

Algebra 2
Find the value of c that makes the expression a perfect square trinomial. Then write the expression as the square of a binomial. I didn't really understand what that meant. x^2-23x+c x^2-(2/7)x+c
December 5, 2011

Chemistry
a sample of gas has the pressure of 1120 mmhg and volume of 2.00 L. if the pressure is changed to 0.155 atm calculate the new volume
November 29, 2011

Calc
Describe in words the set of all points in R³ that satisfy the following expressions: a) z=0 b) z≥0 c) y≤0
November 7, 2011

s.s
I just took this exam and the answer is, in fact, cotton yarn.
November 2, 2011

Calc
Solve: du/dt = (sin t) / (u^2 + 1) So far I got: arctan u = -ln |csc t + cot t| + C I'm not sure where to go from there. Thank you so much for the help!
October 31, 2011

Calc
How do you take the integral of dy/(y^2 + 4)?
October 30, 2011

Calculus
What is the limit as t→∞ of L(t)? L(t) = 34 - 32e^(-0.0719t) Thank you so much!
October 30, 2011

Calculus
Suppose that you follow the size of a population over time. When you plot the size of the population versus time on a semilog plot (i.e., the horizontal axis, representing time, is on a linear scale, whereas the vertical axis, representing the size of the population, is on a ...
October 30, 2011

Calc
Find the integral from -∞ to -1 of 1/(1+x²) dx. I started working the problem out, and so far I got the lim as z→-∞ of [arctan (-1) - arctan (z)]. I'm a little bit confused exactly what is means when you plug -∞ into z, and how to solve the ...
October 24, 2011

Calculus
How do you solve the integral from 0 to 1 of x arctan x dx?
October 24, 2011

Calculus
How do you integrate 3∫(1)/(x²+1)² dx ? Thank you!
October 19, 2011

Calc
Use substitution to evaluate the indefinite integral: The integral of [ (sq. root (1 + ln x)) ((ln x)/x) dx] Im confused on what i should substitute u and du for. Thank you so much!!
October 19, 2011

Calculus
Evaluate the indefinite integral: ∫ from 1 to 2 of ln (x²e^x) dx Thank you for your help!!
October 18, 2011

Calculus
Use either substitution or integration by parts to evaluate the integral: ∫(x+2)/(x²+2) dx Thank you!!
October 18, 2011

Calc
First make an appropriate substitution and then use integration by parts to evaluate the indefinite integrals: ∫ sinx cos³x e^(1-sin²x) dx I was going to substitute u= 1 - sin²x, but then i got du = ½ sinxcosx - ½ xdx, so im stuck. Thank you ...
October 18, 2011

Calc
Use integration by parts to evaluate the integral. ∫ from 1 to 4 of (√x) (ln√x) dx Im not really sure what to choose for u and dv. Thank you so much for the help!!
October 18, 2011

Calculus
F(x) = cos(x) • the integral from 2 to x² + 1 of e^(u² +5)du Find F'(x). When i did this, i got: -2xsin(x)e^((x²+1)² + 5) But my teacher got: -sin(x) • the integral from x² + 1 of e^(u² +5)du + 2xcos(x)e^((x²+1)² + 5) Do ...
October 17, 2011

physics
To plot the potential energy, simply plug your givens into the equation U=(1/2)kx^2. You should get a parabola that goes to 0 in the center. To determine the turning points of the block, use the law of conservation of energy. You know that Ui+Ki = Uf+Kf since there is no ...
October 16, 2011

Statistics
The production process of computer parts uses two machines one old & one new. If the old machine is used the probability that the defected part is produced is .13 if the new machine is used the probability that the defective part is produced is .04. moreover, the new machine ...
October 12, 2011

Physics
F=kx F (tension of the strand)=1.2 pN x (displacement)=26 µm Solve for k, which is the spring constant. You may need to convert your unit measurements, as your answer's unit will come out in pN/µm instead of the standard N/m. (I know this is a little late, but ...
October 12, 2011

Calculus
A particle moves along the x-axis with velocity v(t) = -(t-3)² + 5 for [0,6]. a) Find the average velocity of this particle during the interval [0,6]. b) Find a time t* ∈ [0,6] such that the velocity at time t* is equal to the average velocity during the interval [0...
October 10, 2011

Calc
Recall that the acceleration a(t) of a particle moving along a straight line is the instantaneous rate of change of the velocity v(t); that is, a(t) = d/dt v(t) Assume that a(t) = 32 ft/s². Express the cumulative change in velocity during the interval [0, t] as a definite...
October 10, 2011

Calc
Find the areas of the regions bounded by the lines and curves by expressing x as a function of y and integrating with respect to y. x = (y-1)² - 1, x = (y-1)² + 1 from y=0 to y=2. I graphed the two functions and the do not intersect? Does it matter? Or do I still ...
October 10, 2011

Chem
Calculate the amount (in moles) of H₂O in 2.00g of Na₂CO₃ ⋅ 10H₂O. Thanks so much!!
October 8, 2011

Chem
The field of nanotechnology offers some intriguing possibilities, such as the creation of fibers one atom wide. Suppose you were able to string together 1.00 mol Ag atoms, each of radius 144 pm, into one of these fibers by encapsulating them in carbon nanotubes. How long would...
October 8, 2011

Chem
Calculate the amount (in moles) of Cu²+ ions in 3.00g of CuBr₂. Thank you so much for the help!!
October 8, 2011

Chem
Epsom salts consist of magnesium sulfate heptahydrate. Write its formula. a) How many atoms of oxygen are in 5.15g of Epsom salts? b) How many formula units of the compound are present in 5.15g? c) How many moles of water molecules are in 5.15 g of Epsom salts? Thank you so ...
October 7, 2011

physics
if a car can accelerate at 6m/s2, how fast can it accelerate if it is towin an identical car behind it?
October 5, 2011

Calculus
Assume that a>0. Evaluate the integral from 0 to a of x dx by approximating the region bounded by y=x and the x-axis from 0 to a with rectangles. Use equal subintervals and take right endpoints.
October 2, 2011

History
Was the answer to this question ever determined?
September 28, 2011

Math
^^^kids
September 21, 2011

business
Amyris Biotechnologies was building a plant in 2009 and had synthetic technology to change sugarcane to fuels and chemicals that can be renewed. Their marketing firm was looking for a chemical and a fuel that could be recycled for future use. In 2011, it was decided that the ...
September 21, 2011

Speech
Oh okay I see now. It's just seemed kind of confusing because I have never had a speech class before.
September 21, 2011

Speech
Scrapbooking can be fun and release stress and it can be a good memory for yourself and for your loved ones especially if you have kids. You can also make birthday cards and invitations. More than anything scrapbooking can help you be creative. Does that make sense :/?
September 21, 2011

Speech
My speech can be about anything so I'm going to write and talk about scrapbooking because that is something I enjoy doing.
September 21, 2011

Speech
Hi I have a speech to present and my professor gave me the outline on how to prepare it but I'm having a hard time setting it up. Is their any kind of way you can help me. Thank you, Erica
September 21, 2011

Acct
Journalize the following transactions -Recieved cash from investment made by owner,$15000. Recieved cach providing accounting services, $8000. Billed customers on account for providing services, $4000. Paid Advertising expense 400. Recieved cash from customers on account 3500.
September 20, 2011

College English
I need to write a 700 word essay on what my name means. Can I please get some help!!!
September 19, 2011

English
It needs to be with my first name which is "Erica". Sorry I am new to this website and I did not see your question.
September 19, 2011

English
I have to write a 700 word essay on what my name means ????????????? And I need help!!!!
September 19, 2011

Science
What is the pressure at the bottom of a tube of mercury that is 0.2 m deep? An elephant with a mass of 1000 kg stands on a circus platform that weighs 50 kg. The area of the bottom of the platform is 1.25 m². How much pressure is exerted on the floor beneath the platform...
September 15, 2011

SCIENCE
When the following are placed in water, for which of them will the buoyant force be more than as its weight? A) an ice cube B) a piece of frozen glycerin C) a gold ring D) a piece of aluminum foil 2. Sometimes when I get in my swimming pool I take a plastic cup filled with ...
September 15, 2011

SCIENCE
When the following are placed in water, for which of them will the buoyant force be more than as its weight? A) an ice cube B) a piece of frozen glycerin C) a gold ring D) a piece of aluminum foil 2. Sometimes when I get in my swimming pool I take a plastic cup filled with ...
September 15, 2011

Science
thanks so much
September 11, 2011

Science
A satellite orbiting at an elevation of 3200 km does what a) Stays beyond the earth's gravity, which is why it stays up there. B) in an elliptical orbit, since its speed is less than the escape velocity. C) Falling toward earth with an acceleration equal to g. D) Falling ...
September 11, 2011

Algebra
5(2n + 4) - 3(4n - 6) = 2(20 - n) I solved this equation and this is what I got. 10n + 20 - 12n + 18 = 40 - 2n -2n + 38 = 40 -2n 38 ≠ 40 What does this mean? Thank you!
August 31, 2011

Chemistry
A mixture of gases at 760.0 torr contains 35.0% nitrogen, 22.0% oxygen , and 43.0% carbon dioxide by volume. What is the pressure of the carbon dioxide gas in torr?
August 19, 2011

Greek
The Greek base HELI- means?
July 19, 2011

anatomy and physiology 1
which membrance surround and protect the vital organs in the chest cavity?
July 15, 2011

anatomy and physiology 1
give examples of the various tissue types that exist in your arm. please help me test monday.
July 15, 2011

anatomy and physiology 1
describle two vision disorders that cause abnormal eyeballshape.
July 15, 2011

algebra II
Simplify: a^4-b^4/a-b
July 3, 2011

algebra II
Simplify: (3c^2)(-6cd)^-2
July 3, 2011

physics
Find the final velocity of the two balls if the ball with velocity v2i = -19.5 cm/s has a mass equal to half that of the ball with initial velocity v1i = +26.8 cm/s. PLEASE HELP!! i have tried so many different ways and can't seem to get the answer
June 2, 2011

physics
Find the final velocity of the two balls if the ball with velocity v2i = -19.5 cm/s has a mass equal to half that of the ball with initial velocity v1i = +26.8 cm/s.
June 2, 2011

calculus
3. A deposit of ___(i)___is made into an account paying an interest rate of 5% compounded annually. How many annual payments of ___(iii)___can be made from this account? a) (i)$100,000 (ii)$10,000 b) (i)$200,000 (ii)$20,000 c) (i) 10x (ii) x d) (i) 10x (ii) x at r% compounded ...
June 1, 2011

global history
the wealth that enabled the Italian city-states to lead in the development of Renaissance arts was derived mainly from? a)the quantities of gold and silver brought back to Italian explorers b)concentration of riches in the hands of the king and his court c)their participation ...
May 31, 2011

physical science
you are standing on a street corner, and you hear a fire truck approaching. does the pitch of the siren stay constant, increase, or decrease as it approaches you? does the pitch of the siren stay constant, increase, or decrease as it moves away?
May 23, 2011

stats
A company with a large fleet of cars found that the emissions systems of 18 out of the 65 randomly selected cars they tested failed to meet pollution control guidelines. Is this strong evidence that more than 20% of the fleet might be out of compliance? Test the appropriate ...
May 11, 2011

Calc
To what limit does the sequence Sn = (3+n) /3^n converge as n approaches infinity?
May 3, 2011

Calc
How do you know what shape the graph in the xy-plane represented by x=3sin(t) and y=2cos(t) is?
May 3, 2011

calc
The rate that an object cools is directly proportional to the difference between its temperature ( in Kelvins) at that time and the surrounding temperature (in Kelvins). If an object is initially at 35K, and the surrounding temperature remains constant at 10K, it takes 5 ...
April 25, 2011

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