Most popular questions and responses by bob
  1. Science

    1. Which type of weather technology often carries cameras that can make images of Earth's surface, clouds, and snow cover? A. weather balloon B. weather satellite**** C. computer D. automated weather station 2. Why are weather forecasts more reliable now

    asked on March 19, 2015
  2. math

    Why couldn't the two elephants go swimming together?

    asked on March 17, 2009
  3. Math

    Find the largest $n$ so that $f(2) \cdot f(3) \cdot f(4) \cdots f(n-1) \cdot f(n) < 1.98.$

    asked on February 4, 2016
  4. Math

    A biologist has determined that a particular osprey has a 70% chance of catching a fish on any given day. Carry out a simulation of 20 trials using the random number table below to find the probability that the osprey will actually catch a fish on all of

    asked on May 20, 2014
  5. science

    Which kind of energy transformation occurs when a skater's board falls back to the ramp?

    asked on May 13, 2016
  6. Algebra

    Participants in a study of a new medication received either medication A or a placebo. Find P(placebo and improvement). You may find it helpful to make a tree diagram of the problem on a separate piece of paper. Of all those who participated in the study,

    asked on May 21, 2014
  7. science

    Two stones are launched from the top of a tall building. One stone is thrown in a direction 30.0degree above the horizontal with a speed of 10.0m/s ; the other is thrown in a direction 30.0degree below the horizontal with the same speed. Which stone lands

    asked on September 8, 2008
  8. Chemistry

    a) Which of the following reagents would oxidize Zn to Zn2 , but not Ag to Ag ? Answers are: Co2+ Ca2+ Br2- Br2 Co or Ca b) Which of the following reagents would oxidize Ag to Ag , but not Cl– to Cl2? Answers are: Co Br- Br2 Co2+ Ca2+ or Ca

    asked on June 2, 2014

    Could somebody help me I don't understand any of this. Could someone show me or tell me how to work the problems? 1. Find the length of the hypotenuse of a right triangle with the legs of 9cm and 12cm A.8 B.21 C.15 D.225 2.The length of a hypotenuse of a

    asked on October 18, 2013
  10. Physics

    A woman on a bridge 75.0m high sees a raft floating at a constant speed on the river below. She drops a stone from rest in an attempt to hit the raft. The stone is released when the raft has 7.00m more to travel before passing under the bridge. The stone

    asked on November 19, 2013
  11. social studies

    Which of the following texts contains commentaries on the teachings of Moses? A. the Writings B. the Torah C. the Hebrew Bible D. the Talmud please help i dont want a bad grade again

    asked on September 20, 2018
  12. math

    1. Which of the following numbers is a rational? A. 4/5 B. square root of 27 C. 4.02002000200002... D. Square root of 31 2. Which type of number is shown below? 0.313311333111... A. repeating decimal B. rational C. irrational D. terminating decimal 3.

    asked on September 21, 2016
  13. Chemistry

    In a particular redox reaction, MnO2 is oxidized to MnO4– and Cu2 is reduced to Cu . Complete and balance the equation for this reaction in acidic solution. Phases are optional. MnO2 + Cu^2+ ---> MnO4^- + Cu^+

    asked on May 4, 2014
  14. social studies HELP

    Prior to the destruction of the Second Temple, which of the following areas of the world contained Diaspora communities? A. Central Asia B. Great Britain C. Japan D. Southern Africa

    asked on September 19, 2018
  15. Pre Calculus

    Find all $2 \times 2$ matrices $\bold{A}$ that have the property that for any $2 \times 2$ matrix $\bold{B}$, \[\bold{A} \bold{B} = \bold{B} \bold{A}.\]

    asked on September 20, 2017
  16. English

    these lines of dialogue from the dairy of anne frank, act 1 reveal a lot about anne's character. In the paragraph , explain at least two things that you find out about anne's personality from her words. can someone start me out please im not good at essays

    asked on May 4, 2016
  17. Chemistry

    Balance the following equation for a half reaction that occurs in basic solution. Use e– as the symbol for an electron. SO3^2- ---> S2O4^2-

    asked on May 4, 2014
  18. physics

    a small bead can slide without friction on a circular hoop that is in a vertical plane and has a radius of 0.100 m. The hoop rotates at a constant rate of 3.00 rev/s about a vertical diameter. Find the angle beta at which the bead is in vertical

    asked on October 24, 2011
  19. comprehension science

    how can a cyclist minimize friction as he or she rides?

    asked on May 13, 2016
  20. physics

    Net force F causes mass m1 to accelerate at rate a. A net force of 3F causes mass m2 to accelerate at rate 2a. What is the ratio of mass m1 to mass m2?

    asked on November 5, 2013
  21. Chemistry

    The equilibrium constant, Kp, equals 3.40 for the isomerization reaction: cis-2-butene trans-2-butene. If a flask initially contains 0.250 atm of cis-2-butene and 0.145 atm of trans-2-butene, what is the equilibrium pressure of each gas?

    asked on December 2, 2014
  22. English

    --The Watsons go to Birmingham- 1. Which of the following passages from the novel most accurately reflects the political climate of the United States in the early sixties? A. Let's see, where was the 'Coloreds only' bathroom downtown? B. Bright in the spot

    asked on January 6, 2017
  23. world history

    1. Which of the following would Locke most Favor? A. Republic B. Oligarchy C. Theocracy D. Absolute monarchy

    asked on January 13, 2017
  24. Calculus

    for the function F(t)=ln(t^2), let f(t)=F'(t). Write the integral from a to b of f(t) dt and evaluate it with the fundamental theorem of calculus. the integral from 1 to 3 ___ dt= __

    asked on November 30, 2011
  25. Chemistry

    Carbon dioxide gas has a solubility of 0.0972 g/100 g H2O at 40 degrees celsius. Expressed in parts per million, this concentration is closest to... (1)0.972 ppm (2)9.72 ppm (3)97.2 ppm (4)972 ppm

    asked on February 7, 2012
  26. Chemistry

    Kc is 1.67 × 1020 at 25°C for the formation of iron(III) oxalate complex ion: Fe3+(aq) + 3 C2O42-(aq) [Fe(C2O4)3]3-(aq). If 0.0200 M Fe3+ is initially mixed with 1.00 M oxalate ion, what is the concentration of Fe3+ ion at equilibrium?

    asked on December 2, 2014
  27. Another Chem Problem

    Calculate the total number of F (Fluorine) atoms in 12.15 mol C2HBrClF3. The answer is 2.195 x 10^25 atoms, but I am not sure how they got there. Can anyone give me a hint how to get started? If needed (i'm not sure), the moleculatr mass of C2HBrClF3 is

    asked on March 8, 2009
  28. chemistry

    For the following: i) H3PO4 > H3AsO4 > H3SbO4 ii) H2Te > H2Se > H2S > H2O iii) HCl > HBr > HI iv) SbH3 > AsH3 > PH3 > NH3 The order of acidity is correct for which series? 1. ) all are correct 2. ) i and ii 3. )i, ii and iv 4. ) ii, iii 5. ii, iv I know

    asked on November 24, 2009
  29. math

    Anne wants to tie a support line from the top of a 50 foot radio tower to an anchor spot 30 feet from the tower’s base. Approximately how long will the line need to be?

    asked on June 20, 2013
  30. geometry

    What is the most precise name for quadrilateral ABCD with vertices A(–3, 2), B(–1, 4), C(4, 4), and D(2, 2)? 1. parallelogram 2. rhombus 3. quadrilateral 4. rectangle

    asked on January 11, 2013
  31. chemistry

    consider a crystallization of sulfanilamide in which 10 mL of hot 95% ethyl alcohol is added to 0.10 g of impure sulfanimide. after the solid has dissolved, the solution is cooled to room temp. and then placed into an ice-water bath. no crystals for, even

    asked on October 7, 2008
  32. main ideas

    Scientists generally agree that Earth is getting warmer due to what's called the greenhouse effect. A greenhouse used for plants stays warm because sunlight and heat coming through the glass roof are mostly trapped. The heat doesn't radiate back into the

    asked on September 6, 2013
  33. Physics B

    A car slows down from 23 m/s to rest in a distance of 85m. What is its constant acceleration? I got -6.224, but a friend was telling me it's -3.11 and that I had to divide by 2. Why is that?

    asked on September 12, 2009
  34. Chemistry

    How do you calculate ΔSfus and ΔSvap for HCl given melting point,ΔHfus, boiling point, and ΔHvap also how do you determine the entropy change when 5.20 mol of HCl(l) freezes at atmospheric pressure.

    asked on April 25, 2014
  35. Economics

    A monopoly firm faces a demand curve given by the following equation: P = $500 − 10Q, where Q equals quantity sold per day. Its marginal cost curve is MC = $100 per day. Assume that the firm faces no fixed cost. You may wish to arrive at the answers

    asked on May 3, 2016
  36. Chemistry

    A 0.41 g sample of limestone was dissolved in HCl and all the calcium in the limestone was converted to Ca2+(aq). The solution was treated with excess ammonium oxalate, (NH4)2C2O4(aq), and it was found that 3.0 g of calcium oxalate, CaC2O4(s) was

    asked on September 20, 2012
  37. Algebra

    How do I solve: Translate "y more than 4 is -36". Then solve the problem. Hope someone could help me out with this annoying question!

    asked on November 8, 2015
  38. Chemistry

    40.0 ml of an acetic acid of unknown concentration is titrated with 0.100 M NaOH. After 20.0 mL of the base solution has been added, the pH in the titration flask is 5.10. What was the concentration of the original acetic acid solution? (Ka(CH3COOH) = 1.8

    asked on April 10, 2011
  39. Chemistry

    Which of the following ionic compounds has the highest melting point? Help: Lattice energy Select one: a. Cs2O b. K2O c. BeO d. SrO e. LiF f. CsI

    asked on November 10, 2014
  40. Math

    When Alina was hungry she ate c cookies, which was 30% of all the cookies she had. How many cookies did she have in the beginning?

    asked on April 30, 2017
  41. chemistry

    Calculate the pH and percentage protonation of the solute in an aqueous solution of 0.39 M quinine if the pKa of its conjugate acid is 8.52.

    asked on April 24, 2012
  42. Math ASAP

    In a survey, one out of three people named blue as their favorite color. Two out of seven named red. If 1,092 people were included in the survey, how many named neither blue nor red as their favorite color? A. 416 people B. 432 people C. 540 people D. 512

    asked on February 9, 2017
  43. health

    which is a main factor that accounts for changes in the american family structure 1.casual friends 2.close friends 3.opposite sex friends 4.personal friends

    asked on December 11, 2017
  44. chemistry

    Calculate the number of carbon atoms in 0.75 L of acetone (CH3COCH3). (density = 1.3 g/mL and boiling point = 48.5 degrees Celsius)

    asked on October 31, 2010
  45. physics

    In the vertical jump, an Kobe Bryant starts from a crouch and jumps upward to reach as high as possible. Even the best athletes spend little more than 1.00 s in the air (their "hang time"). Treat Kobe as a particle and let ymax be his maximum height above

    asked on October 21, 2010
  46. Math

    Find the real part of (sqrt{3} - i)^{2011}.

    asked on August 24, 2016
  47. health

    which is a main factor that accounts for changes in the american family structure

    asked on December 11, 2017
  48. english

    Identify the italicized word according to its class in structural linguistics. (There) are no easy answers.

    asked on November 7, 2012
  49. Math

    2. Write a ratio for the situation in three ways comparing the first quantity to the second quantity. In union City, about one in every three homes has two cars A. 5 to 2, 5:2, 5/2 B. 1 to 3, 1:3, 1/3 C. 5 to 3, 5:3, 5/5 D. 3 to 2, 3:2, 3/2

    asked on February 7, 2017
  50. Math, Please Help!!!

    a hot air balloon is rising vertically 10 ft/sec while the wind is blowing horizontally 5ft/sec. Find the speed of the balloon and the angle x that it makes with the horizontal. I know that the speed of the balloon is the square root of (10)^2 + (5)^2, but

    asked on November 10, 2011
  51. pre-algebra

    a bag contains 5 green marbles 2 white marbles 8 blue marbles 9 red marbles and 6 black marbles what is the probability of drawing a white marble replacing it and then drawing a green marble? Answer choices A 1/6 B 1/15 C 1/87 D 1/90 I think its D, but I

    asked on February 17, 2011
  52. Chemistry

    A 150.0 mL sample of a 1.50 M solution of CuSO4 is mixed with a 150.0 mL sample of 3.00 M KOH in a coffee cup calorimeter. The temperature of both solutions and the calorimeter was 25.2°C before mixing and 31.3°C after mixing. The heat capacity of the

    asked on February 18, 2014
  53. science

    what does a cladogram show

    asked on November 20, 2018
  54. physics

    In a Broadway performance, an 80 kg actor swings from a 3.75 m long cable that is horizontal when he starts.? At the bottom of his arc, he picks up his 55.0 kg costar in an inelastic collision. What maximum height do they reach after their upward swing?

    asked on October 16, 2012
  55. Social Studies

    Identify two specific ways the Catholic Church tried to stop the spread of Protestantism

    asked on October 14, 2018
  56. chemisty

    The molar heat capacity of C6H6(ℓ) is 136 J/mol ·◦C and of C6H6(g) is 81.6 J/mol · ◦C. The molar heat of fusion for benzene is 9.92 kJ/mol and its molar heat of vaporization is 30.8 kJ/mol. The melting point of benzene is 5.5 ◦C, its boiling

    asked on January 11, 2012
  57. geometry

    the surface areas of two similar solids are 340 yd2 and 1158 yd2 the volume of the larger solids is 1712 yd3 what is the volume of the smaller solid?

    asked on May 30, 2013
  58. Physics

    A 1200-kg frictionless roller coaster starts from rest at a height of 24 m. What is its kinetic energy when it goes over a spot that is 12 m high?

    asked on May 10, 2012
  59. studies

    Why was inflation a problem after World War II?

    asked on May 8, 2017
  60. Math

    The sum of the three smallest positive values of theta such that 4(cos*theta)(sin*theta) = 1 is k*pi. Find k. Help!!!!!

    asked on June 26, 2016
  61. physics

    A 1000 kg car traveling is at 40.0 m/ s. To avoid hitting a second car the driver slams on his brakes. The brakes provide a constant friction force of 8000 N. ( a) Find the minimum distance that the brakes should be applied in order to avoid a collision

    asked on November 12, 2017
  62. Chemistry

    If Kc = 0.143 at 25°C for this reaction, find the equilibrium concentrations of C6H12 and CH3C5H9 if the initial concentrations are 0.200 M and 0.075 M, respectively. a. [C6H12] = 0.041 M, [CH3C5H9] = 0.041 M b. [C6H12] = 0.159 M, [CH3C5H9] = 0.116 M c.

    asked on January 30, 2011
  63. physics

    A hockey puck slides across the ice at a con- stant speed. Which of the following is true? 1. The puck is moving and thus not in equi- librium. 2. The puck can be considered neither at rest nor in equilibrium. 3. It is in equilibrium. 4. None of these 5.

    asked on October 17, 2011
  64. Physics

    Work of 730 J is done by stirring an insulated beaker containing 80 g of water. What is the change in the temperature of the water? Please show calculation

    asked on October 19, 2011
  65. Statistics

    A car manufacturer is interested in conducting a study to estimate the mean stopping distance for a new type of brakes when used in a car that is traveling at 60 miles per hour. These new brakes will be installed on cars of the same model and the stopping

    asked on November 30, 2009
  66. physics

    A quarterback throws the football to a stationary receiver who is 18.3 m down the field. Football is thrown at an angle of 44.9 degrees to the ground. Acceleration is 9.81 m/s2. What initial spped must the quarterback throw ball to reach receiver and what

    asked on January 19, 2009
  67. chemistry

    Consider the following reaction: CaCN2 + 3H2O ¨ CaCO3 + 2NH3 105.0 g CaCN2 and 78.0 g H2O are reacted. Assuming 100% efficiency, which reactant is in excess and how much is leftover? The molar mass of CaCN2 is 80.11 g/mol. The molar mass of CaCO3 is

    asked on October 31, 2010
  68. Math

    In first gear, or low gear, an automobile's engine runs about three times as fast as the drive shaft. In second gear, the engine does not have to run as fast; usually it runs about 1.6 times faster than the drive shaft. Finally, in third, or high gear, the

    asked on June 17, 2013
  69. Algebra 2

    Claire has borrowed $\$5,\!000$. She plans to pay off the loan in full after two payments. She will make one payment in 3 years, then another payment in 6 years. The second payment will be exactly double the amount of the first payment. How much is the

    asked on April 4, 2017
  70. Microecon help

    Please help! Review for a test and am so lost! (1) An article in the New York Times (Oct. 18, 1990) described a successful marketing campaign by the French champagne industry. The article also noted that “many executives felt giddy about the

    asked on September 3, 2007
  71. Math

    Describe a real world situation that could be represented by planes slicing a three dimensional figure to form cross sections

    asked on March 5, 2017
  72. LCM of two numbers?

    lcm of two numbers pi/3 pi/2 How do I do it? Would it be pi or pi/6? Thanks

    asked on December 15, 2013
  73. Geometry

    Tangent Lines practice problems. Unit 7 3. In the figure below, lines that appear to be tangent are tangent. Point O is the center of the circle. Which is the value of x? I am really confused on this question. If anyone could help that would be great

    asked on April 25, 2018
  74. ap calculus

    a particle moves along the x axis in such a way that its acceleration at time t, t>0 , is given by x(t)= (ln x)^2. at what value of t does the velocity of the particle attain its maximum

    asked on April 5, 2013
  75. trig

    An airplane is flying in the direction 148° with an airspeed of u = 920 kilometers per hour. Because of the wind, its groundspeed and direction are v = 820 kilometers per hour and 140°, respectively (see figure). Find the direction and speed of the wind.

    asked on November 2, 2015
  76. ap chemistry

    Carbon monoxide reacts with oxygen to form carbon dioxide by the following reaction: 2CO + O2 yields 2CO2 Delta H for this reaction is -135.28 kcal. If 811.7 kcal is released, how many moles of CO must have reacted? 1). 270.5 mol 2). 40.5 mol 3). 12.0 mol

    asked on October 18, 2012
  77. chemistry

    Surface tension explains which of the follow- ing phenomena? I) A piece of aluminum foil floating on a lake II) A bowling ball sinking more slowly through molasses than through water III) Separating ethanol from water by distillation IV) Water beading on a

    asked on November 14, 2010
  78. Chemistry

    In the lab, 5.8 L of methane gas is burned with excess oxygen gas at SATP. How much carbon dioxide gas is produced? **Based on the balanced chemical equation the ratio of methane gas to carbon dioxide is 1:1, this being said, does it make sense that as 5.8

    asked on January 10, 2016
  79. Trig

    From a point P on level ground, the angle of elevation of the top of a tower is 27°10'. From a point 23.0 meters closer to the tower and on the same line with P and the base of the tower, the angle of elevation of the top is 51°30'. Approximate the

    asked on June 26, 2012
  80. Chemistry

    An iron ore sample was dissolved in hydrochloric acid and the iron was obtained as Fe2+(aq). The iron solution was titrated with 38.54 mL of 0.471 M Ce4+ solution according to the balanced chemical equation below. Ce4+(aq) + Fe2+(aq) -> Ce3+(aq) +

    asked on March 11, 2009
  81. algebra 2

    During the first part of a trip a canoeist travels 26 miles at a certain speed. The canoeist travels 8 miles on the second part of the trip at a speed 5 mph slower. Total time is 3 hours. What was the seed on each part of the trip

    asked on April 21, 2013
  82. statistics

    A university dean wishes to estimate the average number of hours his part-time instructors teach per week. The standard deviation is 2.6 hours. How large a sample must be selected if he wants to be 95% confident of finding whether the true mean differs

    asked on March 30, 2011
  83. physics

    a 20 kg rock is on the edge of a 100 m cliff . the rock falls from the cliff , what is its kinetic energy just before it hits the ground ?

    asked on February 6, 2012
  84. Chemistry

    Use the dilution relationship (Mi x Vi = Mf x Vf) to calculate the volume of 0.500 M NaOH needed to prepare 500 mL of .250 M NaOH. This is my work ? L Solution = 500mL x (1L/1000mL) = .500L ? mol NaOH = .500 L Solution x (0.250 M NaOH/1 L Solution) = .125

    asked on February 28, 2009
  85. Chemistry

    Calculate the total number of atoms in 0.00102 mol CH3(CH2)4CH2OH The answer in the back of my book says 1.29 x 10^22 but i do not understand how they got to that answer. Will someone please show me how they would set up the problem. I though all you had

    asked on March 8, 2009
  86. Math, Geometry and Physics

    An enemy ship is on the east side of a mountainous island. The enemy ship can maneuver to within 2500 meters of the 1800 meter high mountain peak and can shoot projectiles with an initial speed of 250m/sec. If western shoreline is horizontally 300 meters

    asked on January 16, 2007
  87. Chemistry

    You have a solution that contains 5.0 grams of oxalic acid dissolved in 150 mL of water. This solution is placed in a separatory funnel, and the 100 mL of diethyl ether is added to the separatory funnel and an extraction is performed. Use the following

    asked on October 11, 2011
  88. Math

    Katie makes 65% of her shots from the free throw line. Can you determine how many consecutive free throws she must make in order to increase her percentage to 68%? Explain.

    asked on July 2, 2016
  89. chemistry

    Which of the following is not amphiprotic? a)H2O c)NH4+ e)all choices are amphiprotic b)HSO4 – d)H2PO4– need help!

    asked on March 17, 2012
  90. Trigonometry

    The wheels of a scooter have a diameter of 4.5 inches. If the person riding the scooter is traveling down hill at 15.0 mph. what is the approximate angular speed of the wheels in radians per second

    asked on September 25, 2014
  91. Math

    ABC has vertices A(0, 6), B(4, 6), and C(1, 3). Sketch a graph of ABC and use it to find the orthocenter of ABC. Then list the steps you took to find the orthocenter, including any necessary points or slopes you had to derive.

    asked on December 7, 2012
  92. Calculus

    List x1, x2, x3, x4 where xi is the right endpoint of the four equal intervals used to estimate the area under the curve of f(x) between x = 3 and x = 5. 3, 3.5, 4, 4.5 3, 3.2, 4.6, 5 3.5, 4, 4.5, 5 3.25, 3.75, 4.25, 4.75 my answer was a because i kept

    asked on April 3, 2015
  93. math

    In a geometric series, t1=12 and s3=372.what is the greatest possible value for t5?

    asked on June 3, 2013
  94. geometry

    In the figure below, the measure of arc AC is 88 degrees if angle ABC is equal to 88 degrees.

    asked on February 19, 2012
  95. Chemistry

    Assuming all volume measurements are made at the same temperature and pressure, how many liters of carbon dioxide gas can be produced when 12.8 liters of oxygen gas react with excess carbon monoxide? Show all of the work used to solve this problem.

    asked on March 29, 2011
  96. physics

    A shot putter throws the shot (mass=7.3kg) with an initial speed of 14.4 m/s at a 34.0 degree angle to the horizontal. Calculate the horizontal distance traveled by the shot if it leaves the athlete's hand at a height of 2.10m above the ground.

    asked on October 25, 2018
  97. calculus

    Coroners estimate time of death using the rule of thumb that a body cools about 2 degrees F during the first hour after death and about 1 degree F for each additional hour. Assuming an air temperature of 78 degrees F and a living body temperature of 98.6

    asked on November 18, 2010
  98. Geometry :)

    Use coordinate geometry to prove that the quadrilateral formed by connecting the midpoints of a kite is a rectangle. I have no Idea how to do this problem, so if anyone could help I would be very greatfull. :)

    asked on January 15, 2013
  99. physics

    A spaceship of mass m travels from the Earth to the Moon along a line that passes through the center of the Earth and the center of the Moon. (a) At what distance from the center of the Earth is the force due to the Earth three times the magnitude of the

    asked on December 2, 2011
  100. algebra

    what is the value of 11x^-3y^-1 for x = -1 and y = 2?

    asked on March 3, 2019


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