Popular questions and responses by student
  1. Statistics

    A confidence interval was used to estimate the proportion of statistics students that are females. A random sample of 72 statistics students generated the following 90% confidence interval: (0.438, 0.642). Based on the interval above, is the population

    asked on August 11, 2008
  2. physics

    soo for physics, we did a lab where we launched a cart on a track on the floor and recorded time, distance, etc. to figure out things. one of the questions on the lab is: can you think of a simple follow-up experiment that would allow you to determine how

    asked on October 6, 2009

    During manufacturing of a CIGS device, the metal back contact is deposited first, while in case of the CdTe solar cells, the back contact is deposited in the last processing step. What are the configurations of both cells: a) Both the CI(G)S and CdTe solar

    asked on October 10, 2015
  4. calculus

    The point P(4, −2)lies on the curve y = 2/(3 − x). (a) If Q is the point(x, 2/(3 − x)),use your calculator to find the slope mPQ of the secant line PQ (correct to six decimal places) for the following values of x. 1) 3.9 mPQ= 2) 3.99 mPQ= 3)3.999

    asked on August 28, 2012

    Consider a small module based on interconnected tandem cells of hydrogenated amorphous and microcrystalline silicon as depicted in the figure below. The Voc of a single tandem cell is 1.35V and the short-circuit density Jsc is 12mA/cm2. b)

    asked on October 10, 2015
  6. physics

    A rock is thrown vertically upward with a speed of 14.0 m/s from the roof of a building that is 50.0 m above the ground. Assume free fall. In how many seconds after being thrown does the rock strike the ground? in s What is the speed of the rock just

    asked on September 5, 2011
  7. Data Management (Math)

    A Canadian postal code uses six characters. The first, third, and fifth are letters, while the second, fourth, and sixth are digits. A U.S.A zip code contains five characters, all digits. How many codes are possible for each country?

    asked on June 19, 2011
  8. Chemistry Equilibrium

    Which of the following conditions is always true at equilibrium? deltaG=0, Q=1, K=1, deltaG=deltaG(standard), deltaG(standard)=0, Q=0, deltaG(standard)=1 I'm so confused, please help!

    asked on March 14, 2013
  9. Economics

    A man wishes to bequeath to his daughter P20,000 ten years from now. What amount should he invest now if it will earn interest of 8% compounded annually during the first 5 years and 12% compounded quarterly during the next 5 years?

    asked on June 24, 2018
  10. Math

    How long would it take Belinda's $800 investment to double in value if she has a bond with a 8.75% interest rate?

    asked on March 31, 2020
  11. English

    In The Story of An African Farm, Bonaparte speaks with Otto about the missing sheep. How is this interaction important to the story? It lays the groundwork for Bonaparte and Otto to develop a strong friendship. It clears the way for Otto and Tant Sannie to

    asked on February 28, 2020
  12. math

    okay so i really need help please help i dont understand how to do this ive asked my teacher and i still dont understand is there an easier way to do this to where i could understand? Brayden, Howard, and Vincent are on the football team. During a game,

    asked on April 16, 2018
  13. circuits 2

    Which of the following is true about the cut-off frequency ωB of a first-order low-pass filter? Suppose that the DC gain is 1. a.When the input is a sinusoid operating at ωB, the output is phase shifted from the input phase by −45∘. b.The Bode

    asked on April 6, 2018
  14. Chemistry

    If an electric discharge produces 300 liters of ozone (O3), how many liters of oxygen (O2) are required? 3O2->2O3

    asked on January 21, 2018
  15. chemistry

    Find the formula for the compound that contains 72.4% iron and 27.6% oxygen.

    asked on January 22, 2012
  16. precal

    A pile driver pounds a steel column into the ground. On the first drive, the column is pounded 1.65 metres into the ground, and on each successive drive it moves 80% as far as it did on the previous drive. The least number of drives required to drive the

    asked on October 14, 2012
  17. history

    All of the following statements regarding the Monroe Doctrine are correct EXCEPT? A. Issued by Monroe in response to an onslaught by European monarchies against democracy in the Americas. B. Would have been ineffective without the backing of the British

    asked on February 14, 2012
  18. Chemistry

    The pH of a 0.0050 M aqueous solution of calcium hydroxide is? Make sure to include all equations.

    asked on December 3, 2010
  19. Circuits2

    An alternating current and a direct current flows simultaneously in the same conductor. if the effective value of the alternating current is 5A and the direct current is 10 A, what will an AC ammeter read when connected in the circuit?

    asked on March 26, 2018
  20. Chemistry

    A reaction in which X and Y form products was found to be second order in X and first order in Y. By what factor will the rate of the reaction change if [X] is doubled and [Y] is tripled? a. 10 b. 12 c. 20 d. 2

    asked on February 19, 2015
  21. Circuits 2

    a coil has resistance of 50 ohms and reactance of 70 ohm's. a capacitor is connected in parallel to produce resonance. the source is 120v. what is the power drawn by the circuit ?

    asked on March 25, 2018
  22. Chemistry

    The reaction of CH4 in 2CH4(g) ---->/

    asked on February 28, 2016
  23. civics

    Which of the following would be part of the Republican Party Platform? A. creating a new health care system B. banning hand gun use C. reducing the size of government D. raising taxes on the wealthy I think the answer is C.

    asked on May 30, 2015
  24. Poetry/British Literature/12th grade

    Which of the following poems is a dramatic monologue? (A) "My Last Duchess" (B) "Love Among the Ruins" (C) Childe Roland to the Dark Tower Came (D) all of these

    asked on August 27, 2013
  25. CHEM HELP!

    NH4HSNH3+H2S What is the minimum mass of NH4HS that must be added to the 5.00-L flask when charged with the 0.300g of pure H2S, at 25C to achieve equilibrium?? Kp=.120 at 25C initial pressure of H2S in flask = .0431atm partial pressures of H2S and NH3

    asked on March 12, 2012
  26. chemistry

    You react chemical A with chemical B to make one product. It takes 100 grams of chemical A to react completely with 20 grams of chemical B. What is true about the chemical properties of the product? a. the properties are more like those of chemical A b.

    asked on February 13, 2012
  27. chemistry

    Which of the following is considered a Lewis acid or a Lewis base. I- H2O BCl3 NH3 OH- H+ CO2 SO2

    asked on July 16, 2010
  28. statistics help

    The branch manager of an outlet (Store 1) of a nationwide chain of pet supply stores wants to study characteristics of her customers. In particular, she decides to focus on two variables: the amount of money spent by customers and whether the customers own

    asked on July 28, 2008
  29. Circuits 2

    a circuit with an ideal transformer with a source voltage, Vs=10cos(ωt)V, N1:N2=1:4, and RL=50Ω. What is the magnitude of the current on the primary side of the transformer?

    asked on April 10, 2018
  30. ~*Math Probability*~

    Which expression would you use to figure out the number of ways you can arrange the letters in the word equation? (1 point) 8! 8P4 4P8 4! Five friends are having their picture taken. How many ways can the photographer arrange the friends in a row? (1

    asked on March 13, 2013
  31. Circuits 2

    V1 has rms voltage of Vrms=10V. The turn ratio of the primary to secondary side of the transformer is 1:10. If R1 has a value of 20Ω, what is the value of the rms current on the secondary side? what is the value of the rms current on the primary side?

    asked on April 10, 2018
  32. Circuits 2

    For the circuit below, V1 has rms voltage of Vrms=10V. The turn ratio of the primary to secondary side of the transformer is 1:10. If R1 has a value of 20Ω, what is the value of the rms current on the secondary side? Enter your answer in units of Amps.

    asked on April 9, 2018
  33. Circuits2

    Three impedances zL=3+j4 ohms, zC=4-j4 ohms and zR=0+j3 ohms are connected in parallel. solve for the power factor of the combination.

    asked on March 5, 2018
  34. Math

    A system of equations is shown below: x + y = 3 2x − y = 6 The x-coordinate of the solution to this system of equations is _____. I'm thinking it could be X=3

    asked on December 11, 2015
  35. 9th Grade Algebra

    If a is not equal to 0, and a =2b=3c, what is the value of a+b in terms of c? Would I make up numbers for the variables?

    asked on February 7, 2015
  36. english

    Both texts deal with racial discrimination. How does the structure of poem help convey this meaning in a way that the prose passage does not? A)The poem conveys meaning through imagery; the prose passage does not. B)The poem uses first person point of

    asked on November 6, 2014
  37. Statistics

    A quality control engineer is interested in the mean length of sheet insulation being cut automatically by machine. The desired length of the insulation is 12 ft. It is known that the standard deviation in the cutting length is 0.15 ft. A sample of 70 ut

    asked on August 10, 2008
  38. Chemistry

    Given the following equations, calculate the ΔH of reaction of ethylene gas (C2H4) with fluorine gas to make carbon tetrafluoride (CF4) gas and hydrogen fluoride gas. Show your work. H2 (g) + F2 (g) → 2HF (g) ΔH = –537 kJ C (s) + 2F2 (g) → CF4 (g)

    asked on April 18, 2019
  39. Chemistry-Dr.Bob 222

    1. The rate constant for a second order reaction has units of L mol^-1 s^-1. What are the units of the frequency factor, A, for a second order reaction?

    asked on February 19, 2016
  40. Chemistry

    A solution containing equal masses of glycerol, C3H8O3, and water has a density of 1.10 g/mL. Calculate the molality of glycerol. I got 11.9 m.

    asked on February 14, 2016
  41. Chemistry

    1. As the intermolecular forces between molecules increase in magnitude, do you expect each of the following to increase, decrease or remain the same? My answers: Viscosity: increase Boiling point: increase Vapor pressure: decrease Surface tension:

    asked on February 13, 2016
  42. U.S History

    Which of these describes the location of the Gulf of Mexico? (5 points) South of West Florida East of East Florida*** West of New Orleans South of Great Britain 4. © 2012 The Exploration Company What can you infer about what Lewis and Clark saw as they

    asked on January 5, 2016
  43. Algebra

    The perimeter of a square must be greater than 40 inches but less than 94 inches. Find the range of possible side lengths yay satisfy these conditions.

    asked on January 5, 2016
  44. civics

    A political communication that uses a picture to represent something else is an example of ______. A. bias B. prejudice C. propaganda D. symbolism I think the answer is D.

    asked on May 30, 2015
  45. chemistry

    what are the islamic values in the experiment composition of potassium chlorate?I have to do lab report about the topic and the due date is around the corner.please help me..

    asked on March 14, 2015
  46. Algebra

    I have a word problem here. A batter hits a fly ball. A scout in the stands makes the following observations. Time (in secs) .75, 1.5, 2, 2.75, 3.25, and 4.75 Height (in feet) 77, 133, 160, 187, 194, and 169 1.What type of function best models this data?

    asked on February 28, 2014
  47. Math/Algebra

    A bridge is built in the shape of a semi elliptical arch. It has a span of 96 feet. The height of the arch 29 feet from the center is to be 10 feet. Find the height of the arch at its center.

    asked on May 28, 2013
  48. chemistry

    What mass of water must be added to 0.5 mol of glucose to make a solution of 25 percent by mass?The molar mass of glucose is 180 g/mol.

    asked on January 22, 2012
  49. physics help

    a fireman D=50 m away from a burning building directs a stream of water from a ground-level fire hose at an angle of 30 degrees above the horizontal. If the speed of the stream as it leaves the hose is 40.0 m/s at what height will the stream of water

    asked on October 2, 2011
  50. Algebra 2

    Find the sum of the first six terms of the geometric series 81 -27 +9 -... how do you work it??

    asked on December 12, 2010

    A ball of mass m at rest at the coordinate origin exploded into three equal pieces. At a certain instant, one piece is on the x-axis at x=40cm, and another is at x=20cm, y= -60 cm. Where is the third piece at that instant.

    asked on April 8, 2010
  52. Chemistry

    Baking soda is sodium bicarbonate (NaHCO3). When you heat baking soda, it breaks down into sodium carbonate powder (Na2CO3), water vapor, and carbon dioxide. The enthalpy of this reaction is 129 kJ. Write a correct thermochemical equation for this

    asked on April 18, 2019
  53. Algebra

    I need help with this portfolio and I was wondering if someone could help me understand it. Task 1 Volume and surface area are often compared by manufacturers in order to maximize how much of something can go inside of a package (volume) while keeping how

    asked on May 8, 2018
  54. circuits 2

    a 25ohm resistor connected in series with a coil of 500ohm resistance and 150mH inductance. What is the power factor of the circuit? NOTE: since not given, assume a standard electrical frequency of 60Hz.

    asked on February 5, 2018
  55. I am in class7

    Find the average of 89,90,95,72,83,100,94 with full formula

    asked on July 25, 2017
  56. Psychology

    I wanted to know if someone could give me an example of hypotheses for a 2 x 2 factorial anova

    asked on May 31, 2014
  57. Statistics

    You take a trip by air that involves three independent flights. If there is an 67% chance each specific leg of the trip is on time, what is the probability all three flights arrive on time? (Round your answer to 3 decimal places.) Probability =??

    asked on April 4, 2014

    The earliest and most enthusiastic proponents of Manifest Destiny were: A. Investment Bankers B. Eastern Politicians C. Northeast Industrialists D. Southern Proslavery Advocates E. Protestant missionary groups

    asked on April 17, 2012
  59. chemistry help!!!!!

    Consider the following reaction: Find the equilibrium partial pressures of A and B for each of the following different values of Kp. Assume that the initial partial pressure of B in each case is 1.0 atm, and that the initial partial pressure of A is 0.0

    asked on March 11, 2012
  60. chemistry, chemical kinetics

    I keep getting these questions wrong, could someone please help. Thanks so much. Question 1 For the following overall reaction, the rate constant is 3.4x10^-2. A(g)+ 2B -> 2C + D What may be the rate reaction? Question 2 The rate law for this reaction is

    asked on July 2, 2010
  61. biology

    The length of DNA HELIX occupied by one nucleotide pair is 3.4 angstroms. What is the length in angstroms of this unknown DNA fragment? How do you calculate Angstroms?

    asked on September 17, 2009
  62. Biology

    What types of proteins are made by free proteins and bound ribosomes?

    asked on April 24, 2020
  63. Algebra

    2. Use an augmented matrix to solve the system. x + y = 5 3x – y = –1 (1 point) (1, 4) (1, 5) (3, –1)*** (5, –1) 3. When converting a system of linear equations into an augmented matrix, what equation form is needed? (1 point) slope-intercept form

    asked on January 21, 2019
  64. Social Studies

    1. Which concept did the Maya understand before Europeans did? Architecture Calendars Hieroglyphics The number zero** 2. Which of the following BEST explains how the Mayans adapted their environment? The Mayans developed a nomadic lifestyle to hunt for

    asked on December 6, 2018
  65. Algebra

    Simplify 4*sqrt6/sqrt30 by rationalizing the denominator. 4√6/√30 4√(6/30) 4√(1/5) 4/√5 4√5/5 Am I right?

    asked on May 2, 2018
  66. Circuits 2

    Consider the ideal transformer, where i1(t)=20cos(120πt) Amps and v1(t)=100cos(120πt−45∘) volts, and a = 1 and b = 10. What is the rms value of i2 in amps? what is the amplitude of i2 in amps?

    asked on April 10, 2018
  67. Circuits 2

    let R=20kΩ, L=10mH, and C=40μF. Which angular frequency ω is attenuated most by this filter? (It would help you to first identify what type of filter this is.) Give your answer in terms of rad/sec, and omit units from your answer.

    asked on April 3, 2018
  68. Circuits2

    A series circuit containing a 295 microfarad capacitor and a coil whose resistance and inductance are 3 ohms and 4.42 mH, respectively are supplied by the following series connected generators: 35 V at 60 Hz, 10 V at 180 Hz and 8 V at 240 Hz. Determine the

    asked on March 26, 2018
  69. CIRCUITS 2

    Two relays each with 20 ohms resistance and 0.16 henry inductance are connected in series. What is the equivalent impedance?

    asked on February 12, 2018
  70. Chemistry

    A pyrotechnician mixes 280 g of black powder for a firework. Find the amount of oxygen, carbon dioxide, and sulfur dioxide generated when this firework bursts, if the oxidizing agent in the powder is saltpeter. How do I find their amounts?

    asked on January 21, 2018
  71. Calculus

    he table below shows the temperature (in °F) t hours after midnight in Phoenix on March 15. The table shows values of this function recorded every two hours. (10 points) a. Estimate the value of T'(8). Give units in your answer. b. What is the meaning of

    asked on December 8, 2017
  72. Social Studies

    9. Which of the following statements comparing the Continental and British armies is most accurate? A. The British had more troops and were better disciplined than the Americans. B. The British had limited access to supplies while the American supplies

    asked on October 20, 2016
  73. Physics

    An object is shot upwards, from the ground, with an initial velocity of 120 m/s. How high will it be after 4.0s?

    asked on October 5, 2016
  74. Physics

    An object, initially at rest, is subject to an acceleration if 34 m/s^2. how long will it take for that object to travel 3400m

    asked on October 5, 2016
  75. Art Please Ms.Sue Help

    1.How do landscape paintings convey the values and ideas of Chinese culture? A.Landscape paintings show chaotic, unhappy culture. B.Landscape paintings reveal the importance of natural history to the Chinese. C.Landscape paintings show that Chinese desire

    asked on March 11, 2016
  76. Economics

    4. Deregulation and the Cost of Trucking. Suppose the government initially limits the number of trucking firms that can haul freight. The market for truck freight is served by a single firm that produces five million ton-miles of service per year, where

    asked on February 14, 2016
  77. Chemistry-Dr.Bob

    The solubility of CO2 in water at 25 degrees Celsius and P CO2= 1 atm is 0.034 mol/L. What is its water solubility under normal atmospheric conditions (in air, carbon dioxide is about 380 ppmv assuming that CO2 obeys Henry's Law?

    asked on February 13, 2016
  78. Math, pre-algebra

    The volume of a rectangular prism is 6x^3 -x^2 -2x. Which model could represent the rectangular prism? A. Height: 3x-2 Length: 2x+1 Width: x B. Height: 3x+2 Length: 2x-1 Width: x C. Height: 3x-2 Length: 2x-1 Width: x D. Height: 2x-2 Length: 3x+1 Width: x I

    asked on January 29, 2016
  79. Language Art

    1.)In "The Drummer Boy Of Shiloh", what does the general call the drummer boy? A.)The BRAINS OF THE ARMY b.)The Heart Of The Army C.)The Backbone of the army D.)The PRIDE OF THE ARMY

    asked on September 30, 2015
  80. Math

    your management company was hired to take over the maintenance of the room. last year the old floor tiles were replaced with spanish portico special ceramic tiles. the tiles cost $13.50 per square foot. the owner paid $6534 for the tiles. Determine the

    asked on September 20, 2015
  81. civics

    Which of the following actions is most typical of foreign policy intervention? A. The president creates a new economic plan. B. A task force is asked to investigate a possible free trade violation. C. The Environmental Protection Agency regulates

    asked on May 29, 2015
  82. Science

    Which of the following describes the use of a renewable energy source? A. using natural gas to heat a house B. using a windmill to grind grain C. using petroleum to run a car D. using coal to generate electricity I think the answer is B.

    asked on May 27, 2015
  83. Civics

    Leaders from several states of a nation meet once a year to settle common issues. They govern their own states independently, but they work together on issues that affect them all like trade and defense. They do not have a central government that handles

    asked on April 28, 2015
  84. civics

    Which of the following forces us to make choices? a) scarcity b) trade offs c) opportunity cost d) money

    asked on March 25, 2015
  85. Corporate Finance

    Suppose you have been hired as a financial consultant to Defense Electronics, Inc. (DEI), a large, publicly traded firm that is the market share leader in radar detection systems (RDSs). The company is looking at setting up a manufacturing plant overseas

    asked on March 14, 2015
  86. Math

    There were 25 turkey balloons, 12 pilgrim balloons, and 30 native american balloons. Seventeen of the turkey balloons popped. How many balloons were left?

    asked on March 2, 2015
  87. Math

    Jay's favorite football game was over on Thanksgiving Day at 11:45 a.m. The Thanksgiving dinner was served at 2:15 p.m. How long after the game did Jay have to wait for dinner?

    asked on March 2, 2015
  88. Algebra

    Complete the table for each function. 1. f(x) = √x The x values are 0, 1,4 and 9. The corresponding y values that I got are 0, 1, 2 and 3. 2. g(x) = -1/4√ x The x values are 0, 1, 4, and 9. The corresponding y values that I got are 0, -1/4, -1/2 and

    asked on March 11, 2014
  89. math/algebra

    solve the equation log2(3x-2) - log2 (x-5)=4

    asked on June 23, 2013
  90. Math/Algebra

    Sketch the graph of each piecwise-defined function. Determine the domain and range. Identify each point of discontinuity. f(x)= -x if x

    asked on May 28, 2013
  91. Math/Algebra

    Find the vertex, Focus,and Directrix of the parabola. Graph the equation. y^2=12x

    asked on May 28, 2013
  92. chemistry

    You wish to increase the carbon content of a slab of steel by exposing it to a carburizing atmosphere at elevated temperature. The carbon concentration in the steel before carburization is 165.0 ppm and is initially uniform through the thickness of the

    asked on December 14, 2012
  93. Chemistry

    Complete combustion of 7.70 g of a hydrocarbon produced 23.7 g of CO2 and 10.9 of H2O. What is the empirical formula of the hydrocarbon? I first calculated the moles of both the carbon dioxide and the water, but I have no idea where to go from there. Any

    asked on January 27, 2011

    i have a tritation lab due tomorrow and i am stumped on a couple things. its a titration lab using sodium hydroxide (NaOH)- 250 mL 0.300 M concentration, 10 mL of an unknown substance of vinegar, the avg. of titrated NaOH in the flask with vinegar is 27.7

    asked on December 14, 2008
  95. Stats

    A bank with a branch located in a commercial district of a city has developed an improved process for serving customers during the noon-to-1 p.m. lunch period. The waiting time (operationally defined as the time elapsed from when the customer enters the

    asked on August 13, 2008
  96. chemistry

    I have already posted this and never got a response, please help. here is my data from lab: Buffer1: HPO4- weight 3.412g; original pH Buffer 2: HEPES wt: 1.090g original pH 10.08 buffer1: pH of 0.1M: 7.5; pH of 0.01: 7.72; pH of 0.001M: 7.87 buffer2: PH of

    asked on February 3, 2008
  97. Physics

    A uniform plank of length 5.1 m and weight 235 N rests horizontally on two supports, with 1.1 m of the plank hanging over the right support (see the drawing). To what distance x can a person who weighs 458 N walk on the overhanging part of the plank before

    asked on October 8, 2007
  98. math, help

    I need help or hint on the setup: what is the probability that at least 2 students in a class of 36 have the same birthday? This is 1 minus the probability that all students have different birthdays. Suppose that the birthday of a student is completely

    asked on July 15, 2007
  99. math,help & correction

    the question asks: How many 5-card poker hands consisting of 2aces and 3 kings are possible with an ordinary 52-card deck? this is what i did: "c"=stands for combination (4C2) * (4C3) = 6*4 = 24 (52C5) = 259860 so then i divided : (24)/(259860)=

    asked on July 15, 2007
  100. Algebra

    The perimeter of a soccer field is 340m. The length exceeds width by 50m. Find the Length and Width.

    asked on February 15, 2020


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