Most popular questions and responses by eric
  1. science

    Which of the following gases was most likely present in Earth's earliest atmosphere? a. nitrogen b.hydrogen c.argon d.oxygen Help me please!

    asked on September 13, 2018
  2. Physics

    A rocket-powered hockey puck moves on a horizontal frictionless table. The figure below shows the graphs of vx and vy, the x- and y-components of the puck’s velocity. The puck starts at the origin. The graph of the X-velocity is v=8t cm/s and the

    asked on September 11, 2015
  3. Math

    The 3rd and 7th terms of an A.P are -1 and 11 respectively. Fine the nth term and the numbers of which must be added to get a sum of 430

    asked on September 20, 2017
  4. Math

    Which of the images above represents a proof of the Pythagorean Theorem? Explain your choice, and then explain how the figure proves the Pythagorean Theorem.

    asked on November 19, 2012
  5. chemistry

    Assuming equal concentrations, rank these aqueous solutions by their freezing point.? K2CO3, Li3PO4, Sn(ClO3)4, NH4I I tried to rank them according to the number of ions but i can't get it. highest freezing point --> lowest freezing point Sn(ClO3)4 ->

    asked on February 19, 2012
  6. chemistry

    A crystalline material containing 30 grams of barium chloride crystals was placed into an oven at 400 degrees c and heated for two hours. It was then cooled and weighed. the new mass was less than before it was heated, containing 20 grams if barium

    asked on January 27, 2011
  7. physics

    a 65kg person dives into the water from the 10m platform. she comes to a stop 2m below the surface of the water. what net force did the water exert on the swimmer? so for the net force i got -2548N i know: vf^2=vi^2 + 2ad vf^2 = 0 + 2(9.8)(10) vf^2 = 196

    asked on February 6, 2014
  8. Math

    Paul is painting a square wall with an area of 115 square feet. To the nearest foot, what is the length of the wall? Hint: A = s2. 11 29 42 58

    asked on November 19, 2012
  9. physics

    The same amount of heat entering identical masses of different substances produces different temperature changes. Calculate the final temperature when 1.25 kcal of heat enters 1.25 kg of the following, originally at 20.0°C. (a) water (b) concrete (c)

    asked on July 19, 2013
  10. Physics-Trajectory

    A particle's trajectory is described by x =(12t3−2t2)m and y =(12t2−2t)m, where t is in s. What is the particle's speed at t=0s ? What is the particle's speed at t=5.0s ? Express your answer using two significant figures. What is the particle's

    asked on September 11, 2015
  11. Chem HELP!!

    Which one of the following sets of quantum numbers can correctly represent a 3p orbital? a) (n = 3 l = 1, ml = 2) b)(n = 1, l = 3, ml = 3) c) (n = 3, l = 2, ml = 1) d) (n = 3, l = 1, ml = -1) e) (n = 3, l = 0, ml = 1)

    asked on October 5, 2014
  12. Introduction to computers

    Which Microsoft operating system started the process of authenticating users with a username and password

    asked on November 10, 2015
  13. Physics

    A massive steel cable drags a 20kg block across a horizontal, frictionless surface. A 100N force applied to the cable causes the block to reach a speed of 4.2m/s in a distance of 2.1m . What is the mass of the cable?

    asked on May 30, 2015
  14. Physics

    A ball of mass m makes a head-on elastic collision with a second ball (at rest) and rebounds with a speed equal to one-fourth its original speed. What is the mass of the second ball?

    asked on December 10, 2009
  15. Chemistry

    When carbon is burned in air, it reacts with oxygen to form carbon dioxide. When 26.4 g of carbon were burned in the presence of 82.1 g of oxygen, 11.7 g of oxygen remained unreacted. What mass of carbon dioxide was produced? Express your answer to one

    asked on September 14, 2016
  16. Spanish

    Are these correct? I. Rewrite each sentence by replacing the direct object in quotation marks with a direct object pronoun [me, te, lo, la, nos, los, las]. Ejemplo: No conozco "al jefe del departamento." --> No lo conozco. 1. Esa compañía vende "casas

    asked on January 23, 2014
  17. ChemII

    A saline solution is 0.9% NaCl. What masses of NaCl and water would be required to prepare 50. L of this saline solution? Assume that the density of water is 1.000g/mL and that the NaCl does not add to the volume of the solution.

    asked on January 9, 2011
  18. Physics

    When a 65 kg person climbs into a 1000 kg car, the car's springs compress vertically by 3.1 cm. What will be the frequency of vibration when the car hits a bump? Ignore damping.

    asked on January 27, 2010
  19. Math

    The population of town A increases from 1,346 to 1,500. In the same period, the population of town B increases from 1,546 to 1,800. a. Find the percent of increase in population for town A and for town B. b. Which town had the greater percent of increase?

    asked on December 13, 2012
  20. Educational Technology and Online Learning

    what is the purpose of the introduction in an expository essay

    asked on September 14, 2016
  21. physics

    A projectile is fired in such a way that its horizontal range is equal to 8.5 times its maximum height. What is the angle of projection?

    asked on February 18, 2011
  22. physics

    Rubbing your hands together warms them by converting work into thermal energy. If a woman rubs her hands back and forth for a total of 12 rubs a distance of 7.50 cm each and with a frictional force averaging 30.0 N, what is the temperature increase? The

    asked on July 19, 2013
  23. physics

    A firefighter a distance d from a burning building directs a stream of water from a fire hose at angle θi above the horizontal as in the figure. If the initial speed of the stream is vi, at what height h does the water strike the building? (Use theta for

    asked on February 18, 2011
  24. physics

    The engine of a large ship does 2.05 multiplied by 108 J of work with an efficiency of 4.00%. (a) How much waste heat (J) is produced? (b) How many barrels of fuel are consumed, if each barrel produces 6.00 multiplied by 109 J of heat when burned?

    asked on July 24, 2013
  25. chemistry help~Please!!!

    What are the Ka and/or Kb value for 1M ZnCl2 Show work please!!!

    asked on April 11, 2014
  26. Chemistry

    The vapor pressure, P, of a certain liquid was measured at two temperatures, T. Represented in a table: T (in Kelvin) ------- P(in kPa) [325] --------------- [4.00] [775] --------------- [8.59] What is the enthalpy of vaporization for this liquid? (Delta H

    asked on January 23, 2012
  27. chemistry

    A 141-mg sample was placed on a watch glass that weighed 9.203 g. What is the weight of the watch glass and sample in grams?

    asked on January 31, 2012
  28. college physics

    A(n) 13,300 lb railroad car traveling at 7.4 ft/s couples with a stationary car of 6790 lb. The acceleration of gravity is 32 ft/s^2. What is their velocity after the collision (ft/s)? And what impulse did the first car receive? Answer in units of lbs. Any

    asked on March 23, 2010
  29. Math

    Simplify (Log75+log9+log5)÷(log5+log45)

    asked on November 10, 2016
  30. physics

    In 1986 a gargantuan iceberg broke away from the Ross Ice Shelf in Antarctica. It was approximately a rectangle 160 km long, 45.0 km wide, and 250 m thick. (a) What is the mass of this iceberg, given that the density of ice is 917 kg/m3? (b) How much heat

    asked on July 20, 2013
  31. Chemistry

    A solution is made by dissolving 0.500 mol of HF in enough water to make 1.00 L of solution. At 21 C, the osmotic pressure of the solution is 1.35 atm. What is the percent ionization of this acid? This is what i did.. is it correct? (1.35 atm) =

    asked on February 19, 2012
  32. physics

    In a local bar, a customer slides an empty beer mug down the counter for a refill. The bartender is momentarily distracted and does not see the mug, which slides off the counter and strikes the floor at distance d from the base of the counter. The height

    asked on February 18, 2011
  33. physics 11

    A swimmer swims perpendicular to the bank of a 20.0 m wide river at a velocity of 1.3 m/s. Suppose the river has a current of 2.7 m/s [W]. (a) How long does it take the swimmer to reach the other shore? (b) How far downstream does the swimmer land from his

    asked on October 20, 2015
  34. Math

    What is the sqaure root of thirty six over forty nine?

    asked on November 19, 2012
  35. Math

    Thinking about the different types of numbers you learned in this unit, how would you help someone remember the differences between rational and irrational numbers? Remember to mention some of the Key Words from your lessons

    asked on November 19, 2012
  36. physics

    A magician pulls a tablecloth from under a 200 g mug located 30.0 cm from the edge of the cloth. The cloth exerts a friction force of 0.105 N on the mug, and the cloth is pulled with a constant acceleration of 3.50 m/s2. How far does the mug move relative

    asked on February 24, 2011
  37. physics

    A certain heat engine does 8.0 kJ of work and dissipates 8.00 kJ of waste heat in a cyclical process. (a) What was the heat input to this engine? (b) What was its efficiency?

    asked on July 24, 2013
  38. physics

    A hand-driven tire pump has a 2.50 cm diameter piston and a maximum stroke of 31.0 cm. (a) How much work (J) do you do in one stroke if the average gauge pressure is 2.40 multiplied by 105 N/m2 (about 35 psi)? (You may consider this an isothermal process.)

    asked on July 24, 2013
  39. chemistry

    a certain radioactive nuclide has a half life of 5.00 hour. Calcuate the decay rate for 1.000 mole of this nuclide __________ decay s-1

    asked on July 12, 2012


    asked on November 19, 2007
  41. math, economics, game theory

    Two people have 10 dollars to divide between themselves. they use the following procedure. each person names a number of dollars (nonnegative integer), at most equal to 10. IF the sum of the amounts that the people name exceeds 10 and the amounts named are

    asked on September 10, 2007
  42. statistics

    Scores on the GRE​ (Graduate Record​ Examination) are normally distributed with a mean of 541 and a standard deviation of 101. Use the 68-95-99.7 Rule to find the percentage of people taking the test who score between 238 and 844 The percentage of

    asked on December 8, 2016
  43. math

    Mrs. Bollo's second grade class of thirty students conducted a pet ownership survey. Results of the survey indicate that 8 students own a cat, 15 students own a dog, and 5 students own both a cat and a dog. How many of the students surveyed own no cats?

    asked on November 28, 2010
  44. physics

    The "steam" above a freshly made cup of instant coffee is really water vapor droplets condensing after evaporating from the hot coffee. What is the final temperature of 280 g of hot coffee initially at 90.0°C if 2.50 g evaporates from it? The coffee is in

    asked on July 21, 2013
  45. physics

    (a) A rectangular gasoline tank can hold 41.0 kg of gasoline when full. What is the depth(m) of the tank if it is 0.400 m wide by 0.900 m long? (b) What is the volume(gal) of the tank? (It is suitable for a passenger car.)

    asked on July 22, 2013
  46. accouting

    Nancy Company has budgeted sales of $300,000 with the following budgeted costs: Direct materials $60,000 Direct manufacturing labor 40,000 Factory overhead Variable 30,000 Fixed 50,000 Selling and administrative expenses Variable 20,000 Fixed 30,000

    asked on April 2, 2011
  47. Spanish

    Are these correct? Thank you for helping Finish the following sentences including at least one possessive adjective (mi[s], tu[s], su[s], nuestro[s] or nuestra[s]) in your answer. Ejemplo: La profesora que tiene mi amiga es antipática, pero "mis

    asked on January 24, 2014
  48. chemistry

    E degrees (V) A galvanic cell based on the following half reaction s Au3+ 3e- ----> Au 1.50 Mg2+ 2e- ------> Mg -2.37 The cell is set up at 25 C with [Mg2+] = 1.00 x 10^-5 M The cell potential is observed to be 4.01 V. Calculate the [Au3+] that must be

    asked on July 13, 2012
  49. physics

    About 50,000 years ago, in an area located outside Flagstaff, Arizona, a giant 4.5x10^7 kg meteor fell and struck Earth, leaving a 180 m hole now known as Barrington crater. If the meteor was traveling 20000 m/s upon impact, with what average force did the

    asked on March 3, 2011
  50. Chemistry

    The specific heat of a certain type of metal is 0.128 J/(g-c). What is the final temperature if 305 J of heat is added to 86.9 g of this metal initially at 20 degrees C? Tfinal = ___ C

    asked on February 8, 2012
  51. Physics

    A soft drink can contains about 0.20 kg of liquid at 5 oC. Drinking this liquid can actually consume some of the fat in the body, since energy is needed to warm the water to body temperature (37 oC). How many kcal should the drink have so that it is in

    asked on September 20, 2010
  52. Introduction to computers

    You call the help desk to report a problem you are having on your computer. The technician asks you what operation system you are running. You know it is windows 7 but you forgot which version . How can you find out.

    asked on November 10, 2015
  53. Physics

    two skaters, each of mass 55 kg, approach each other along parallel paths separated by 3.8 m. They have opposite velocities of 1.9 m/s each. One skater carries one end of a long pole with negligible mass, and the second skater grabs the other end of it as

    asked on June 2, 2012
  54. science

    How do you calculate how long will it take an object dropped from a window to fall a distance of 78.4 meters?

    asked on October 17, 2011
  55. Calculus

    Find the value(s) of c guaranteed by the Mean Value Theorem for Integrals for the function over the given interval. f(x) = 4√x [4, 9]

    asked on November 15, 2016
  56. Spanish

    Are these correct? Answer the following questions using the present progressive. Be sure to answer with the same verb that is used in each question. 1. Creo que Xavier (1) _____ (2) __________ en la casa de sus padres mientras asiste a la Universidad.

    asked on January 29, 2014
  57. statistics

    Suppose 1,600 of 2,000 registered voters sampled said they planned to vote for the Independent candidate for president. Using the 0.95 degree of confidence, what is the interval estimate for the population proportion (to the nearest tenth of a percent)?

    asked on February 2, 2013
  58. Chemistry

    A 50.0-mL sample of 0.10 M HNO2 is titrated with 0.10 M NaOH. What is the pH after 25.0 mL of NaOH have been added?

    asked on December 7, 2010
  59. Physics

    Three positive point charges are located at the corners of a rectangle. Find the electric field at the fourth corner if q1 = 5 nC, q2 = 6 nC, and q3 = 7 nC. The distances are d1 = 0.6 m and d2 = 0.2 m. (Let the positive x-direction be to the right, and the

    asked on January 18, 2016
  60. Chemistry

    You have a 22L cylinder of helium at a pressure of 150atm and a temperature of 31C. How many ballons can you fill, each with a volume of 5.0L, on a day when the atmospheric pressure is 755mmHg and the temperature is 22C?

    asked on September 27, 2009
  61. Math

    Martin used some apples to make muffins.Omar used 5 fewer than half as many apples as Martin used

    asked on March 12, 2019
  62. english

    chick: a young woman A. direct definition B. indirect definition a

    asked on February 18, 2012
  63. Algebra

    Tell whether the lines for each pair of equations are parallel perpendicular of neither y=-3x+7 -2x+6y=3 Tell whether the lines for each pair of equations are parallel perpendicular of neither y=(-1/5)x=6 -2x+10y=5

    asked on January 18, 2016
  64. physics

    A 1.80 m radius playground merry-go-round has a mass of 120 kg and is rotating with an angular velocity of 0.300 rev/s. What is its angular velocity after a 19.0 kg child gets onto it by grabbing its outer edge? The child is initially at rest.

    asked on July 18, 2013
  65. college

    Two point charges have a total charge of 505 µC. When placed 1.10 m apart, the force each exerts on the other is 19.3 N and is repulsive. What is the charge on each? (Round your answers to the nearest µC.)

    asked on August 29, 2010
  66. Math

    A class has 27 students. Fifteen are boys and the rest are girls. What is the ratio of girls to total students? 12 : 15 15 : 12 27 : 12 12 : 27

    asked on November 20, 2012
  67. Chemistry

    You have a 22L cylinder of helium at a pressure of 150atm and a temperature of 31C. How many ballons can you fill, each with a volume of 5.0L, on a day when the atmospheric pressure is 755mmHg and the temperature is 22C? I know I use PV=nRT, but what

    asked on September 27, 2009
  68. Chemistry

    Using the equation: 2C2H6 + 7O2--> 4CO2 + 6H20 How many moles of CO2 are produced by the reaction of 21.0 mol O2? Again, not sure how to write it correctly, but if I multiply 7O2 by 3, then I should do the same to the other side of the equation to make it

    asked on February 19, 2016
  69. physics

    An ice bag containing 0°C ice is much more effective in absorbing heat than one containing the same amount of 0°C water. (a) How much heat in kcal is required to raise the temperature of 0.700 kg of water from 0°C to 27.0°C? (b) How much heat is

    asked on July 19, 2013
  70. english

    what does miss rosie symbolize in the poem miss rosie by lucille clifton?

    asked on May 18, 2010
  71. Math

    Nell made a pizza. she cut the pizza into fourths. then she cut each fourth. nell and her friens ate 6 of the smaller pieces of the pizza. What fraction of the pizza did Nell and her friends eat? What fraction of the pizza did Nell and friends Not eat?

    asked on December 4, 2014
  72. Economics

    The well known nationally syndicated columnist David Broder reported the recent findings of two academic political scientists. These scholars found that voters are quite turned off by negative campaigns of politicians. Many people went as far as not voting

    asked on July 15, 2013
  73. physics

    In 1986 a gargantuan iceberg broke away from the Ross Ice Shelf in Antarctica. It was approximately a rectangle 160 km long, 45.0 km wide, and 250 m thick. (a) What is the mass of this iceberg, given that the density of ice is 917 kg/m3? (b) How much heat

    asked on July 21, 2013
  74. Algebra 2

    Create an explicit equation for each recursively defined sequence below a1=17,an+1=an-7

    asked on October 13, 2015
  75. math

    A 10 kg quantity of a radioactive isotope decays to 3 kg after 17 years. Find the decay constant of the isotope.

    asked on February 3, 2011
  76. Physics

    Three forces are exerted on an object placed on a tilted floor. Forces are vectors. The three forces are directed as shown in the figure. If the forces have magnitudes F1 = 2.0 N, F2 = 17.0 N and F3 = 15.0 N, where N is the standard unit of force, what is

    asked on September 11, 2015
  77. Algebra

    Gymnast Clothing manufactures expensive soccer cleats for sale to college bookstores in runs of up to 500. Its cost (in dollars) for a run of x pairs of cleats is C(x) = 3000 + 9x + 0.1x2 (0 ≤ x ≤ 500). Gymnast Clothing sells the cleats at $130 per

    asked on February 19, 2012
  78. Economics

    Thomas Schelling, an expert on nuclear strategy and arms control, observed in his book The Strategy of Conflict (Cambridge, MA: Harvard University Press, 1960), "The power to constrain an adversary depends upon the power to bind oneself." Explain this

    asked on July 15, 2013
  79. history

    Hamilton / Jefferson Readings Quiz 1. Alexander Hamilton thought that having a virtuous citizenry was a necessity in a Repulic. A) True B) False 2. Who said "The goodness of a government consists in a vigorous execution?" A) Thomas Jefferson B) Alexander

    asked on May 1, 2012
  80. physics

    One side of the roof of a building slopes up at 35.5°. A student throws a Frisbee onto the roof. It strikes with a speed of 15.0 m/s and does not bounce, but slides straight up the incline. The coefficient of kinetic friction between the plastic and the

    asked on February 24, 2011
  81. physics

    one ball is dropped off a cliff. A second ball is thrown down 1 second later with an initial speen of 40 ft/sec. How long after the second ball is thrown will the second ball overtake the first?.

    asked on May 11, 2011
  82. Organic Chem

    A 20 g mixture containing 95% (by weight) of A and 5% of B is recrystallized in toluene (b.p. 110 C). Solubility for compound A is 1.5 g @20 degrees and 10 g @ 110 degrees. For compound B solubility is 0.5 g @20 degrees and 8 g @ 110 degrees. What amount

    asked on October 5, 2010
  83. french

    how do you conjugate aimer mieux? do you just conjugate the aimer part?

    asked on February 9, 2008
  84. chemistry

    How much faster will neon effuse than krypton, given that the molar mass of krypton is 83.8 grams and that of neon is 20.18 grams?

    asked on July 14, 2013
  85. College Physics

    A concept question: Suppose that the centripetal force acting on an object in circular motion were increased to a new value, and the object remained in circular path with the same radius. How would its motion be affected?

    asked on September 30, 2010
  86. Chemistry

    How many calories are required at 0 degrees C to melt an ice cube with a mass of 25g? I got 2000 cal. Could you tell me if this is right?

    asked on September 18, 2010
  87. Physics

    One kind of slingshot consists of a pocket that holds a pebble and is whirled on a circle of radius r. The pebble is released from the circle at the angle θ so that it will hit the target. The angle in the drawing is 35.5°. The distance to the target

    asked on September 28, 2012
  88. math

    A 10 kg quantity of a radioactive isotope decays to 3 kg after 17 years. Find the decay constant of the isotope.

    asked on February 3, 2011
  89. Math

    Ann, Mara, Jenny, Tina, and Sue are sisters. Two of the five sisters must help their father at this business each Saturday. How many combinations of two sisters are possible?

    asked on September 13, 2011
  90. Math

    The new facility is the square in shape the link of one of the walls is 20 feet how many square feet is the facility

    asked on December 12, 2017
  91. Math

    How many inches represent 1 mile. Help 3/10 in = 7/8 mile

    asked on December 8, 2016
  92. Calc

    Find the critical numbers of the functions. f(0) = 2sec0 +tan0 on the interval [0,2pi]

    asked on November 15, 2016
  93. math

    A company made $4 million in the second quarter. This is 1/3 more than it made in the first quarter and 4/5 of what it made in the third quarter. How much did the company make in the three quarters combined?

    asked on September 19, 2011
  94. Yoku

    A prism has total surface area of 360 m2 and volume of 60 m3. If the length, width, and height are reduced to half their original sizes, what will be the following?

    asked on March 15, 2010
  95. Algebra

    21. simplify (2sqrt5+3sqrt7)^2 show your work. Been confused on it for a while.

    asked on May 8, 2017
  96. Physics

    The intensity of a particular earthquake wave is measured to be 5.0 multiplied by 106 J/m2·s at a distance of 55 km from the source. (a) What was the intensity when it passed a point only 3.0 km from the source? (b) What was the rate energy passed through

    asked on January 31, 2010
  97. math

    Katrina is studying the effect of foreign substances on bacteria populations. If she introduces a beneficial substance, such as food, the bacteria population grows. If she introduces a harmful substance, such as a poison, the bacteria population decreases.

    asked on October 30, 2014
  98. Physics

    What will be the equilibrium temperature when a 245 g block of copper at 285 oC is placed in a 145 g aluminum calorimeter cup containing 825 g of water at 12.0 oC?

    asked on September 20, 2010
  99. u.s. history

    imagine you are living in the united states in the 1890's. write a letter to the president persuading him to support or oppose an imperialismt policy for the united states. be sure to use standard grammar, spelling, sentences structure, and punctuation.

    asked on August 24, 2008
  100. Algebra 2

    Solve each system 3x-9y=3 and 2x=16-y

    asked on October 11, 2015


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