Popular questions and responses by Rachel
  1. Physics

    Please Help ! A child throws a snowball at a tree and it sticks to the tree. Does this motion defy the Law of Conservation of Momentum? Explain. The Law of Conservation of Energy states: "If there is no net force acting on a system of objects, the total

    asked on November 9, 2009
  2. Chem

    A sealed container holding 0.0255 L of an ideal gas at 0.989 atm and 71 °C is placed into a refrigerator and cooled to 45 °C with no change in volume. Calculate the final pressure of the gas.

    asked on March 7, 2018
  3. Chemistry

    3NO2(g) + H2O(l) → 2HNO3(aq) + NO(g) standard enthalpy: -133.5 Find the change in internal energy for this reaction. Enter in kJ.

    asked on October 21, 2014
  4. math

    A test had 200 questions .Each correct answer carried 2 marks.Each wrong answer carried -1/2 marks and unanswered question fetched no marks .Ajay attempted all the question in the test and he scored 360 marks.What would his marks be, if for each correct

    asked on November 28, 2014
  5. Chemistry 12

    The molar heat of vaporization of water is 42 kJ/mol. How much energy is released by the condensation of 3.0 g of water? So for water there will just be one mol. I think this is how you do it, but it doesn't match the answer in the worksheet. q=mc delta t

    asked on December 10, 2015
  6. physics conservation of momentum

    A 0.5 kg ball is thrown horizontally towards a wall with a speed of 10 m/s. The initial velocity is chosen to be the positive x-direction for this question. The ball horizontally rebounds back from the wall with a speed of 10 m/s in the negative

    asked on November 8, 2008
  7. PRE-CAL

    Complete the table for the time t (in years) necessary for P dollars to triple when interest is compounded continuously at rate r. (Round your answers to two decimal places.) R=2% t=? tried to plug in as A=Pe^rt since continiously 3=e^.02t ? then take the

    asked on September 17, 2016
  8. Pre calc

    sin(θ − ϕ); tan(θ) = 5/12 θ in Quadrant III, sin(ϕ) = − sqaure root 10/10 ϕ in Quadrant IV I tried this numerous times can somone please help me

    asked on April 12, 2017
  9. Physics

    A barge with mass 1.7×105 kg is proceeding down river at 6.1 m/s in heavy fog when it collides broadside with a barge heading directly across the river. The second barge has mass 2.83×105 kg and was moving at 4.2 m/s. Immediately after impact, the second

    asked on November 3, 2009
  10. Geometry

    A gardener wants the three rosebushes in her garden to be watered by a rotating water sprinkler. The gardener draws a diagram of the garden using a grid in which each unit represents 1 ft. The rosebushes are at (1, 3), (5, 11), and (11, 4). She wants to

    asked on May 20, 2012
  11. statistics

    In a survey of 5100 TV viewers, 40% said they watch network news programs. Find the margin of error for this survey if we want 95% confidence in our estimate of the percent of TV viewers who watch network news programs. Hint, find the CI using 1-PropZInt,

    asked on September 13, 2010
  12. Physics

    A child's game consists of a block that attaches to a table with a suction cup, a spring connected to that block, a ball, and a launching ramp. By compressing the spring, the child can launch the ball up the ramp. The spring has a spring constant k, the

    asked on November 7, 2008
  13. math

    A rectangular playground is to be fenced off and divided in two by another fence parallel to one side of the playground. Five hundred and forty feet of fencing is used. Find the dimensions of the playground that maximize the total enclosed area. What is

    asked on December 10, 2017
  14. Chemistry

    what is the name for the following coordination compounds or ions? 1. [Al(H2O)6] Br3 2. [Cr(NH3)6] Cl3 3. K3[FeF6] 4. [Zn(OH)4]-2

    asked on December 4, 2008
  15. chemistry

    A pure copper cube has an edge length of 2.00cm. How many copper atoms does it contain? (volume of a cube = (edge length)^3; density of copper = 8.96g/cm^3 )

    asked on October 26, 2010
  16. math

    Find x so that QS || PT PQ = 8, QR = 5, RS = 15, ST = x + 3

    asked on December 9, 2017
  17. chemistry

    In the reaction 2SO2 (g) + O2 (g) 2SO3 (g), which change would cause the greatest increase in the concentration of SO3?

    asked on May 3, 2011
  18. phyics

    A dart leaves the barrel of a blowgun at a speed v. The length of the blowgun barrel is L. Assume that the acceleration of the dart in the barrel is uniform. Find a time that the dart moves inside the barrel. Express your answer in terms of the variables L

    asked on September 19, 2015
  19. chemistry

    What is Delta H rxn for the following chemical reaction? H2O(l) + CCl4(l)-> COCl2(g) + 2HCl(g)

    asked on September 4, 2011
  20. chemistry

    Determine the theoretical yield of C when each of the following amounts of A and B are allowed to react in the generic reaction: A+2B-->3C 1) 1mol A; 1 mole B 2) 1mole A; 3 mole B 3) 2mole A; 2 mole B 4) 32mole A; 68 mole B

    asked on November 10, 2010
  21. Physical Science

    A 0.6-g peanut is burned beneath 50 g of water, which increases in temperature from 22degreesC to 50 degreesc. What is the exact food value of the peanut? (Assuming a 40% efficiency)

    asked on February 27, 2008
  22. pre calc

    To measure the height of the cloud cover at an airport, a worker shines a spotlight upward at an angle 75° from the horizontal. An observer D = 600 m away measures the angle of elevation to the spot of light to be 45°. Find the height h of the cloud

    asked on March 27, 2017
  23. Geometry

    The equation (x + 6)^2 + (y + 4)^2 = 36 models the position and range of the source of a radio signal. Describe the position of the source and the range of the signals.

    asked on May 30, 2012
  24. calculus

    water is poured into a conical paper cup so that the height increases at the constant rate of 1 inch per second. if the cup is 6 inches tall and its top has a radius of 2 inches, how fast is the volume of water in the cup increasing when the height is 3

    asked on October 16, 2011
  25. physics

    Suppose a cylindrical habitat in space 7.70 km in diameter and 25.0 km long has been proposed. Such a habitat would have cities, land, and lakes on the inside surface and air and clouds in the center. They would all be held in place by rotation of the

    asked on March 11, 2011
  26. calcius

    Determine whether the function is linear, constant, or neither y = x3 - x2 + 8 a. Linear b. Constant c. Neither I think it is neither

    asked on June 9, 2008
  27. chem

    A hot air balloon is filled with 1.51 × 106 L of an ideal gas on a cool morning (11 °C). The air is heated to 103 °C. What is the volume of the air in the balloon after it is heated? Assume that none of the gas escapes from the balloon.

    asked on March 6, 2018
  28. Chemistry

    What is the hybridization of phosphorous in a P4 molecule

    asked on September 25, 2012
  29. chemistry

    Lead is often found in Earth's crust as several lead compounds. Calculate the mass in kilograms of the amount of each of the following lead compounds that contains 4500kg of lead. 1)PbCO3 (cerussite) 2) PbSO4(anglesite)

    asked on October 26, 2010
  30. physics

    Two very long, straight, parallel wires carry currents that are directed perpendicular. Wire 1 carries a current I1 into the page (in the -z direction) and passes through the x axis at x = +a. Wire 2 passes through the x axis at x = -2a and carries an

    asked on April 9, 2011
  31. Physics

    Suppose that in the same Atwood setup another string is attached to the bottom of m1 and a constant force f is applied, retarding the upward motion of m1. If m1 = 5.30 kg and m2 = 10.60 kg, what value of f will reduce the acceleration of the system by 50%?

    asked on October 24, 2009
  32. Chemistry

    I know how to find half-lives, but I have trouble finding the length of time it would take for the concrentration of X to decrease to Y% of its initial value. For example, this is one of the problems: Methyl isocyanide, CH3NC, isomerizes when heated to

    asked on December 16, 2006
  33. math

    how to find the height of a trapezoid with median 12 and area 84

    asked on January 24, 2011
  34. science

    Four racecars are driving at constant speeds around a circular racetrack. The data table gives the speed of each car and each car’s distance from the center of the track at one instant. Car Speed (m/s) Position (m) A 40 20 B 40 25 C 50 20 D 50 25 Rank

    asked on November 29, 2015
  35. Algebra

    A kite is tied to the ground. The rays from the sun hit the kite perpendicular to the kite string, casting a shadow of the kite on the ground. The coordinates in the diagram are given in feet. What is the distance from where the kite is tied to the shadow?

    asked on November 19, 2014
  36. Chemistry

    Fish breathe the dissolved air in water through their gills. Assuming the partial pressures of oxygen and nitrogen in the air are to be .20 atm and .80 atm respectively, calculate the mole fractions of oxygen and nitrogen in the air dissolved in water at

    asked on May 31, 2014
  37. Calculus

    Let g and h be any two twice-differentiable functions that are defined for all real numbers and that satisfy the following properties for all x: I) (g(x))^2 + (h(x))^2=1 ii) g'(x)= (h(x))^2 iii) h(x)>0 iv) g(0)=0 a)Justify that h'(x)=-g(x)h(x) for all x b)

    asked on January 30, 2014
  38. Physics

    A certain spring stretches 5.8cm when a load of 38N is suspended from it. How much will the spring stretch if 48N is suspended from it (and it doesn't reach its elastic limit)?

    asked on November 10, 2013
  39. Physics

    A loaded penguin sled weighing 60 N rests on a plane inclined at 20° to the horizontal. Between the sled and the plane the coefficient of static friction is 0.27, and the coefficient of kinetic friction is 0.13. (a) What is the minimum magnitude of the

    asked on February 19, 2013
  40. Chemistry

    A base has a Kb of 2.5 x 10–11. Which of the following statements is true? This is a concentrated base. This base ionizes slightly in aqueous solution. This is a strong base. An aqueous solution of this base would be acidic.

    asked on March 9, 2012
  41. algebra

    Including a 9% sales tax, an inn charges $127.53 per night. Find the inns nightly cost before tax is added

    asked on January 14, 2012
  42. Physics

    A parallel-plate capacitor is made from two plates 12.0cm on each side and 4.50mm apart. Half of the space between these plates contains only air, but the other half is filled with Plexiglas of dielectric constant 3.40. An 18.0 V battery is connected

    asked on March 3, 2011
  43. Gen Chem 1

    A tanker truck carrying 2.01×10^3kg of concentrated sulfuric acid solution tips over and spills its load. The sulfuic acid is 95.0% H2SO4 by mass and has a density of 1.84g/L. Sodium Carbonate (Na2CO3)is used to neutralize the the sulfuric acid spill. How

    asked on October 6, 2010
  44. Physics

    A pilot of mass 65 kg in a jet aircraft makes a complete vertical circle in mid-air. The vertical circle has a radius of 1.70 km at a constant speed of 215 m/s. Determine the force of the seat on the pilot at (a) the bottom of the loop and (b) the top of

    asked on October 29, 2009
  45. Algebra

    After visiting the Titanic, Captain Brain and Mr. Pinky are taking the Alvin submarine back to the surface of the water. They start 1500 meters below the surface of the water, and ascend at 37 meters per hour. Note: under the water is a negative number.

    asked on June 25, 2016
  46. Physics

    The magnitudes of the four displacement vectors shown in the drawing are A = 14.0 m, B = 11.0 m, C = 12.0 m, and D = 25.0 m. Determine the (a) magnitude and (b) direction for the resultant that occurs when these vectors are added together. Specify the

    asked on September 16, 2015
  47. physics

    Two hypothetical planets of masses m1 and m2 and radii r1 and r2, respectively, are nearly at rest when they are an infinite distance apart. Because of their gravitational attraction, they head toward each other on a collision course. Note: Both the energy

    asked on March 11, 2011
  48. physics

    A solid copper object hangs at the bottom of a steel wire of negligible mass. The top end of the wire is fixed. When the wire is struck, it emits sound with a fundamental frequency of 300 Hz. The copper object is then submerged in water so that half its

    asked on February 16, 2011
  49. algebra

    The Big Screamer Coaster carries 92 people altogether. Some of its cars carry 4 passengers, and the rest carry 6 passengers. There are three less 6-passenger cars than 4-passenger cars. How many 4-passenger cars are there?

    asked on August 10, 2010
  50. Geometry

    A flat screen television is advertised as being 59 inches on its diagonal. If the TV is 13 inches tall, then how wide is the screen?

    asked on May 30, 2017
  51. Math

    Your baseball team has won 6 games and lost 4 games.if the team doesn't lose any more games,how many games must the team win to have a win:lose ratio of 2:1

    asked on February 18, 2016
  52. Physics

    An electron has an initial speed of 4.00×106 m/s. What potential difference (sign and magnitude) is required to bring the electron to rest?

    asked on October 19, 2015
  53. Physics

    Speed: A block lies on a horizontal frictionless surface. A horizontal force of 100 N is applied to the block, giving rise to an acceleration of 3 m/s2. What is the speed of the block after 10s? I think I would just multiple the two and put it in terms of

    asked on February 25, 2015
  54. Chemistry

    An archeological artifact was subjected to radiocarbon dating. The artifact showed a carbon-14 decay rate of 13.8 disintegrations/ min per gram of carbon. Carbon-14 has a half-life of 5715 years, and currently living organisms decay at the rate of 15.3

    asked on December 5, 2014
  55. Physics

    1. Two points in a plane have polar coordinates (2.5 m, 30 degrees) and (3.8 m, 120 deg). Determine (a) the cartesian coordinates of both points and (b) the distance between the points. 2. Vector A has magnitude 29 units and points along +y. When vector B

    asked on February 17, 2014
  56. Physics

    A ball is shot from the ground into the air. At a height of 9.1 m, the velocity is observed to be v = (6.6 + 5.7 ) m/s, with horizontal and upward. (a) To what maximum height does the ball rise? m (b) What total horizontal distance does the ball travel? m

    asked on February 5, 2013
  57. Physics

    A small ball rolls horizontally off the edge of a tabletop of height h. It strikes the floor a distance x horizontally away from the edge of the table. (Use any variable or symbol stated above along with the following as necessary: g.) (a) How long is the

    asked on February 4, 2013
  58. Physics

    A concave mirror is constructed so that a man at a distance of 19 cm from the mirror sees his image magnified 2.0 times. What is the radius of the curvature? OK so I have tried to work this out and can't seem to find the answer. Here is what I got. Please

    asked on October 28, 2012
  59. Statistics

    On average 3 % of a certain type of TV tube burn out before their guarantee has expired. If a merchant sells 120 such tubes, find the probability that he will be forced to replace at least 3 of them (Use the Poisson approximation to the Binomial

    asked on February 15, 2011
  60. Chem. Again

    28: You have a glass of pure water. Are chemical reactions occurring in the water? If so, what are they? If not, explain why not. 29: While investigating the effects of acid rain in your area, you discover a lake that is surprisingly resistant to changes

    asked on May 12, 2009
  61. Physics

    Three vectors are shown in the figure. Their magnitudes are given in arbitrary units. Determine the sum of the three vectors. Give the resultant in terms of (a) magnitude and (b) the angle within the positive x axis.

    asked on September 24, 2018
  62. Chemistry

    The Haber process developed to produce fertilizer from nitrogen and hydrogen, is governed by the following unbalanced reaction: a N2 + b H2 -> c NH3 . If 10.5 kg of NH3 product is required, how many kg of hydrogen are required if nitrogen is in excess?

    asked on October 24, 2017
  63. phyics

    Consulting the graph shown in (Figure 1) , determine the object's average velocity over the time interval from 2 to 4 seconds. Express your answer in meters per second to the nearest integer. Position versus time graph for an object traveling with a

    asked on September 13, 2015
  64. math

    The sum of two numbers is 4 and the reciprocal of one exceeds the reciprocal of other by twice the product of their reciprocals. What is the product of the reciprocals of two numbers? Please help me solving.

    asked on December 8, 2014
  65. Chemistry

    Temperature is a measure of the amount of heat an object contains. T/F

    asked on December 6, 2014
  66. Chemistry

    Identify the predominant intermolecular forces between molecules of each of the following compounds: a. CCl4 b. HF c. SO2 d. CH3COOH e. HI

    asked on September 7, 2013
  67. Math

    The management of a private investment club has a fund of $114,000 earmarked for investment in stocks. To arrive at an acceptable overall level of risk, the stocks that management is considering have been classified into three categories: high-risk,

    asked on September 10, 2012
  68. chemistry

    Aqueous silver nitrate reacts with aqeous potassium iodide in a double-replacement reaction to produce a precipitate of silver iodide. If 34.6 ml of 0.563 M silver nitrate are used with 148.4 ml of potassium iodide: a) What molarity of potassium iodide

    asked on December 6, 2011
  69. calculus

    Let P= (V^2)R / (R+r)^2 Calculate dP/dr, assuming that r is variable and R is constant.

    asked on September 26, 2011
  70. organic chemistry

    how do you increase the yield of triphenylmethanol in a grignard reaction?

    asked on March 8, 2010
  71. organic chemistry

    how do you increase the yield of triphenylmethanol in a grignard reaction?

    asked on March 8, 2010
  72. math

    Determine whether QS || PT . Justify your answer. PQ = 18, QR = 6, RS = 12, ST = 36

    asked on December 9, 2017
  73. Geometry

    TV screens are measured on the diagonal. If we have a TV-cabinet that is 72 inches long and 64 inches high, how large a TV could we put in the space (leave 2-inches on all sides for the edging of the TV)? Round your answer to the nearest tenth.

    asked on June 2, 2017
  74. Math

    Jim has $87. He spends $6 for socks and at least $32 for shoes. How much does he have left to spend on shirts? I know the answer is >49 I need to find the inequality equation. Thank you

    asked on September 27, 2016
  75. physics

    a particle executing shm time period t from mean position the time to complete 5/8 oscillation

    asked on June 26, 2016
  76. Math Literacy

    I really don't know how to begin to approach this problem. A 6-year-old patient underwent an outpatient tonsillectomy and adenoidectomy The surgeon ordered 1,000 cc D5W, dispensed at a rate of 600 cc every 8 hours, to maintain hydration levels. A

    asked on January 16, 2016
  77. Algebra 1

    A pyrotechnician plans for two fireworks to explode together at the same height in the air. They travel at speeds shown at the right. Firework B is launched 0.25 s before Firework A. How many seconds after Firework B launches will both fireworks explode?

    asked on April 13, 2015
  78. chemistry

    The number of protons in an anion must always be ________ the number of electrons. the same as We can’t tell. less than greater than

    asked on December 6, 2014
  79. chemistry

    A metal oxide will form an acid when it is dissolved in water. T/F

    asked on December 6, 2014
  80. Physics

    What is the spring constant of a spring that stores 25 J of elastic potential energy when compressed by 6.0 cm from its relaxed length?

    asked on February 27, 2013
  81. Geometry

    Two sides of a rhombus form a 120º angle. The length of each side is 6 in. Explain how to find the area of the rhombus, and then calculate the area. Leave your answer in simplest radical form.

    asked on February 14, 2012
  82. Chemistry(check my work)?

    An equilibrium mixture of the following reaction was found to have [COF2] = 0.255 M and [CF4] = 0.118 M at 1000°C. What is the concentration of CO2? 2 COF2(g) ---> CO2(g) + CF4(g) Keq = 2.00 at 1000°C I know I need to put the numbers in the equation so

    asked on April 17, 2011
  83. physics

    An accelerating voltage of 2.46 * 10^3 V is applied to an electron gun, producing a beam of electrons originally traveling horizontally north in vacuum toward the center of a viewing screen 34.0 cm away. What is the magnitude of the deflection on the

    asked on April 9, 2011
  84. Physics

    A small m = 2.00 g plastic ball is suspended by a L = 24.0 cm long string in a uniform electric field, as shown in Figure P15.50. If the ball is in equilibrium when the string makes a 18.0° angle with the vertical as indicated, what is the net charge on

    asked on February 1, 2011
  85. chemistry

    write a net ionic equation for the following: Copper (II) sulfate reacts with Ammonium hydroxide to produce Copper (II) oxide, Ammonium sulfate, and water.

    asked on October 26, 2010
  86. Phsyics

    A bullet of mass 1.8 X 10-3 kg is moving at +500. m/s when it impacts a tree stump. It penetrates into the stump 6.00 centimeters before coming to rest. 1. Assuming the acceleration to be constant, calculate the force (including direction) exerted by the

    asked on October 26, 2010
  87. Persuasive Topic help

    For my speech class we need to make a speech on a persuasive topic that will be interesting and fun to hear. It needs to be a topic that no one ever really talks about, or something that no one really knows about. For example pregnancy is something we

    asked on October 14, 2010
  88. calculus

    Find the volume of the solid formed by rotating the region enclosed by y=e^(3x)+2, y=0, x=0, and x=.2 about the y-axis

    asked on February 17, 2010
  89. Physical Science

    In your room are things such as tables, chairs and other people. Which of these things has a temperature lower than air? Greater than air? And equal to the temperature of air?

    asked on March 1, 2008
  90. Economics

    Graph the supply and demand curves of Qd=500 - 2P and Qs = -100 + 3P

    asked on September 15, 2007
  91. chem

    If 6.64 moles of C5H12 reacts with excess O2, how many moles of CO2 will be produced in the following combustion reaction? Can plz explain how to do it Thank You

    asked on February 12, 2018
  92. science

    How would you separate a mixture of small beads, sand, iron filings, salt, and water, using a magnet, filter funnel, filter paper, bunsen burner and a tripod with a bunsen burner? I thought of Filtration, Evaporation, Distillation, Magnetism, and even

    asked on May 13, 2017
  93. Math, Quadratic equaitons

    A toy rocket is launched form a 3m platform, at 8.2m/s. The height of the rocket is modelled by the equation h=-4.0t^2+8.1t+3 where h is the height, in metres, above the ground and t is the time, in seconds. After how many seconds will the rocket rise to a

    asked on November 20, 2016
  94. Chemistry

    For the reaction, calculate how many grams of the product form when 3.2 g of CaO completely reacts. Assume that there is more than enough of the other reactant. CaO(s)+CO2(g)→CaCO3(s)

    asked on July 17, 2016
  95. Algebra

    Geppetto is a puppet maker. He starts the month with 3 puppets ready to sell, and makes 9 puppets per day. Write an equation to model this situation (use d for days and p for puppets).

    asked on June 25, 2016
  96. Science(physics)

    A spring 20cm long is stretched to 25cm by a load of 50N. What will be its length when stretched by 100N assuming that the elastic limit is not reached? I want the answer abd solving to this question and also the formula for young modulus of elasticity

    asked on January 19, 2016
  97. phyics

    A car takes 11 s to go from v=0m/s to v = 22 m/s at constant acceleration. If you wish to find the distance traveled using the equation d=1/2at2, what value should you use for a? Please help on this i don't know what i should put i think m/s squared but i

    asked on September 19, 2015
  98. science

    1. Tommy performed an experiment to test the solubility of sodium chloride in water. After he completed his experiment, he discovered that he had a few unused grams of NaCl leftover in a beaker. What should he do with the excess NaCl? A. Pour the excess

    asked on October 27, 2014
  99. AP Calc. AB

    1.If an arrow is shot upward on the moon with a velocity of 50 m/s its height (in meters) after t seconds is given by H = 50t - 0.66t2. With what velocity will the arrow hit the moon? a. -49.5 b. -47 c. -50.1 d. -50 e. -51 2.If an arrow is shot upward on

    asked on September 28, 2014
  100. Math

    3 similar shirts and 4 similar jackets cost $360. 1 such shirt and 3 such jackets cost $220. Find the cost of each shirt.

    asked on February 16, 2014


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