Popular questions and responses by S
  1. Physics

    A boy on a swing is pulled to a position 2.34 m off the ground and released. At the fastest and lowest point of the swing the boy is 0.50 m off the ground and travelling 3 m/s. The percent efficiency of this swing system is: A) 70 % B) 25% C) 50% D) 10%

    asked on July 28, 2020
  2. math

    If the line 3x-4y = 0 is tangent in the first quadrant to the curve y = x^3 + k, then k is

    asked on December 28, 2011
  3. physics

    a glass lens has a convex surface with a radius 25.0 cm and a concave surface with radius 50.0 cm with the glass refraction = 1.51 calculate the focal length

    asked on March 30, 2014
  4. Physics

    Consider a piece of metal that is at 5 deg C. If it is heated until it has twice the internal energy, its temperature will be. a)556 deg C b)283 deg C c)273 deg C d)278 deg C e)10 deg C

    asked on November 19, 2012
  5. Chemistry

    An aqueous solution is 8.50% ammonium chloride, NH4Cl, by mass. The density of the solution is 1.024g/mL. Calculate the molality, mole fraction, and molarity of NH4Cl in the solution. I know the formulas needed but I'm not sure where to start. M = moles

    asked on January 24, 2012
  6. physics

    Two forces 4N and 5N are inclined to each other at 30°, find the resultant force by parallelogram method

    asked on September 12, 2019
  7. Physical Chemistry

    15.The Rydberg constant for the Be3+ ion is 109731 cm–1. Calculate the ionization energy of a ground-state Be3+ ion. 22.How many electrons can occupy the following subshells: (a) 2s, (b) 4d, (c) 6f, (d) 6g, (e) 6h?

    asked on August 8, 2017
  8. Physics

    A horizontal forces of magnitude 500N pulls two blocks of masses m1=10 kg and m2=20 kg which are connected by the light inextensible string and lying on the horizontal frictionless surface. Find the tension in the strings and acceleration of each mass when

    asked on November 5, 2016
  9. statistics

    A manufacturer claims that the mean lifetime of its lithium batteries is 1400 hours. A homeowner selects 25 of these batteries and finds the mean lifetime to be 1380 hours with a standard deviation of 80 hours. Test the manufacturers claim. Use alpha =

    asked on December 5, 2015
  10. physics

    A tennis ball is shot vertically upward in an evacuated chamber inside a tower with an initial speed of 20.0 m/s at time t = 0 s. Approximately how long does it take the tennis ball to reach its maximum height?

    asked on September 13, 2014
  11. chemistry

    A gas absorbs 25kj of heat and does 12kj of work calculate (triangle) E

    asked on April 16, 2013
  12. Algebra

    A wire is stretched from the ground to the top of an antenna tower. The wire is 15 feet long. The height of the tower is 3 feet greater than the distance d from the tower's base to the end of the wire. Find the distance d and the height of the tower.

    asked on September 15, 2019
  13. physics

    A man holds a 185-N ball in his hand, with the forearm horizontal (see the figure). He can support the ball in this position because of the flexor muscle force , which is applied perpendicular to the forearm. The forearm weighs 24.3 N and has a center of

    asked on October 28, 2014
  14. Physics

    Lead has a density of 11300 kg/m^3 at 0 degrees celcius. What is the density of lead at 90 degrees celcius?

    asked on November 14, 2012
  15. physics

    In Problems 1-5, we will work through an example of QFTM for M=6 What is ω? You can use e, pi, and M in your response. Please do not subtitute 6 for M. What is QFT6 of 12√(|0⟩+|3⟩)? Specify the probability amplitudes. You should use w to denote ω,

    asked on March 22, 2013
  16. algebra

    solve for x: 2x+3y=8

    asked on September 26, 2010
  17. chemistry

    An automobile maker has an order for 7,500 new cars to be delivered in one week. Each car must be fitted with a new hood ornament that requires 1 hour and 15 minutes to install. Assuming the factory operates on a standard workweek shift (8 hours per day

    asked on August 20, 2013
  18. chemistry

    are these right? How many atoms are there in 1.3x10^22 molecules NO2? atoms=(1.3x10^22 molecules NO2) x (2atoms/1molecule) = 2.6x10^22 atoms NO2 A 5.0g sample of O2 is in a container at STP. How many atoms of oxygen are in the container? atoms = (5.0g O2)

    asked on December 14, 2008
  19. stat

    Construct a 90% confidence interval for the population mean. Assume the population has a normal distribution. A same of 15 randomly selected math majors has a grade point average of 2.86 with a standard deviation of 0.78. Round to the nearest hundredth.

    asked on December 5, 2015
  20. physics

    A car is travelling around a banked curve at a constant speed of 84.0 km/h. If the radius of curvature of the path is 67.0 m, and there is no friction between the car and the surface, at what angle (in degrees) should the bank be set at, relative to the

    asked on October 15, 2018
  21. AP Chemistry

    For the system 2SO2(g) + O2(g) 2SO3 (g), change in enthalpy is negative for the production of SO3. At a particular temperature, 8.00 moles of sulfur dioxide and 10.00 moles of sulfur trioxide are introduced into a 2.00 L container. The system is allowed to

    asked on January 12, 2008
  22. statistics

    A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial

    asked on December 5, 2015
  23. MATH


    asked on January 27, 2011
  24. math

    determine the product 800.5*(2*10^6)

    asked on April 5, 2018
  25. physics

    Suppose we have |ϕ⟩=∑y∈{0,1}nβy|y⟩ such that βy=0 if s⋅y=1mod2 and βy=12(n−1)/2 if s⋅y=0mod2, where s is some hidden n-bit string. (a) If we run Fourier sampling on |ϕ⟩, what is the probability that we see s?

    asked on March 4, 2013
  26. History

    What is the point of no return in the Civil War? I was deciding between the Compromise of 1850, Bleeding Kansas, or Brown and Harpers Ferry. I just need some opinions on which one I should choose, I can back up all of them with evidence. Thanks!

    asked on May 7, 2020
  27. Math

    on a map 1/2 inch represents 50 miles. How long would a line need to be to represent 750 miles. so I thought I should divide 750 by 50 than multiply 15 { the answer I got } by 1/2 but I have a feeling its wrong

    asked on April 26, 2017
  28. chemistry

    The Henry's law constant for CO2 is 3.1 x 10-2 mol/L-atm at 25°C. What pressure would be necessary in order to have a .25 M solution?

    asked on February 5, 2015
  29. Physics

    Suppose the surface (radius = r) of a cylindrical space station is rotating at 29.1 m/s to provide artificial gravity. What must be the value of r for the astronauts to weigh 1/3 of their earth weight? Don't know how to start please help.

    asked on October 20, 2014
  30. Physics

    If a supersaturated sugar solution is allowed to evaporate slowly, sugar crystals form in the container. Hence, sugar molecules go from a disordered form (in solution) to a highly ordered, crystalline form. Does this process violate the second law of

    asked on November 25, 2012
  31. Chemistry

    Is (NH4)2 CO3 ionic or covalent?

    asked on January 31, 2012
  32. algebra

    percent means hundredth true or false?

    asked on October 30, 2010
  33. Math

    In ΔABC, m∠C = 118 and m∠B = 44. Which is the shortest side of the triangle A. AB B. BC C. AC

    asked on January 3, 2010
  34. English

    Which sentence below contains a correctly used modifier? a) He spoke "sharply" to his sister. b) I feel "goodly" now that I'm over the flu. c) The sauce tasted "bitterly", and I couldn't swallow it. d) Joe looked "sad" at his broken bike. Appreciate the

    asked on November 28, 2007
  35. English

    Which one of the following is a correct example of the singular possessive case? 1) women's club 2) audiences' reaction 3) who's job 4) king's rights

    asked on November 28, 2007
  36. Calculus

    Which equation is the polar equivalent to the equation y=−(√3/3)x? θ=π/6 θ=π/3 θ=2π/3 θ=5π/6

    asked on May 19, 2020
  37. MATH

    john poured 2 1 / 2 liters of water into a tank. then he poured out 3 2 / 5 liters of water from the tank , leaving 4 1 over 5 liters of water in the tank how much water was in the tank at first?

    asked on October 3, 2018
  38. chemistry

    Air consists of 21 % oxygen, 78 % nitrogen and 1 % argon by volume. Calculate: * (a) the partial pressures in Pa, if total pressure is 1 atm, * (b) the concentration in mol m–3, of each gas at 273 K, * (c) the average molar mass of air, * (d) the number

    asked on November 21, 2017
  39. Chemistry

    High quality coal (anthracite) is almost pure carbon. The combustion of carbon to carbon dioxide releases 393 kJ per mol of carbon burnt. If 1.000 kg of anthracite is burnt: (i) How much heat is released? (ii) How much ice (in kg) at 273 K could be melted

    asked on November 21, 2017
  40. MATH

    During halftime of a football​game, a sling shot launches​ T-shirts at the crowd. A​ T-shirt is launched from a height of 33 feet with an initial upward velocity of 64 feet per second. The​ T-shirt is caught 48 feet above the field. How long will

    asked on January 8, 2017
  41. Physics

    a 35 kg child slides down a 26 degree incline. the coefficient of kinetic friction is 0.33. what is her speed after sliding for 2.5 seconds starting from rest?

    asked on February 13, 2016
  42. Physics

    a stone is thrown at an angle of 30 degrees above the horizontal from the top edge of a cliff with an initial speed of 12m/s. a stop watch measures the stone's trajectory time from top of cliff to bottom to be 8s. how far out from the cliff's edge does the

    asked on January 28, 2016
  43. Math

    solve: cot(2theta/3)= -sqrt3 Please help, I don't know how to start and how to set it up.

    asked on September 29, 2014
  44. physics

    An Olympic long jumper leaves the ground at an angle of 18.7 ° and travels through the air for a horizontal distance of 7.04 m before landing. What is the takeoff speed of the jumper?

    asked on September 19, 2014
  45. physics

    The depth of the ocean is sometimes measured in fathoms (1 fathom = 6 feet). Distance on the surface of the ocean is sometimes measured in nautical miles (1 nautical mile = 6076 feet). The water beneath a surface rectangle 3.70 nautical miles by 2.80

    asked on September 13, 2014
  46. Physics

    A spherical shell of radius R carries a uniform surface charge density (charge per unit area) σ. The center of the sphere is at the origin and the shell rotates with angular velocity ω (in rad/sec) around the z-axis (z=0 at the origin). Seen from below,

    asked on April 26, 2013
  47. physics

    Given circuits for f and f−1, we can create classical reversible circuits Rf, R−1f, Rf−1, R−1f−1 which are shown in the following figure. (Assume that f is a bijection.)In what sequence shall we apply the above circuits in order to implement a

    asked on March 6, 2013
  48. physics

    A baseball player puts a baseball on a batting tee. The baseball bat is able to deliver 400,000 W of power and is in contact with the ball for 0.70 ms and a distance of 1.4 cm. the mass of the ball is 145g. What is the average acceleration?

    asked on November 7, 2012
  49. Stats

    Cans of regular Coke are labeled as containing 12. Statistics students weighted the content of 10 randomly chosen cans, and found the mean weight to be 12.1. Assume that cans of Coke are filled so that the actual amounts are normally distributed with a

    asked on October 20, 2012
  50. chemistry

    These are short and simple. :) I've included my answers, tell me if I am wrong please. CH3 is attached to a carbon on a pentane ring. Is the hybridization of the carbon sp3? NH connects a benzene ring to two benzene rings. Is the hybridization of the

    asked on March 16, 2011
  51. chemistry

    aluminum reacts with sulfric acid to produce aluminum sulfate and hydrogen gas. how many grams of aluminum sulfate would be form if 250 g H2SO4 completely reacted with aluminum?

    asked on November 30, 2009
  52. English/Word Usage

    Which of of the following is a correct example of the plural possessive case? 1) stone's throw 2) men's plan 3) it's place 4) woman's plan

    asked on November 28, 2007
  53. chemistry

    can someone explain to me how to answer this: Polycarbonate plastic has a density of 1.2 g/c3. A photo frame is constructed from two 3.0 mm sheets of polycarbonate. Each sheet measures 28 cm by 22cm.What is the mass of the photo frame?

    asked on October 7, 2007
  54. chemistry

    1.how do you calculate the specific heat of a metallic element if 314 joules of energy are needed to raise the temperature of a 50.0 g sample from 25.0 degrees c to 50.0 degrees c. 2. how do you propose a method for determining the specific heat for a

    asked on October 2, 2007
  55. History

    Which statement BEST describes a principle that is shared in the preambles of the constitutions of the United States and Georgia? A. Government originates from the people B. Government offers peace and prosperity* C. Government helps all of its people D.

    asked on February 7, 2020
  56. math

    Find the periodic payment R required to amortize a loan of P dollars over t years with interest charged at the rate of r%/year compounded m times a year. (Round your answer to the nearest cent.) P = 11,000, r = 4, t = 4, m = 2

    asked on November 18, 2019
  57. Statistics

    1) Let z be a normal random variable with mean 0 and standard deviation 1. The 4th decile of z is ___. a) 0.67 b) –1.25 c) -0.25 d) 1.28 e) 0.50 2) According to the central limit theorem, if a sample of size 50 is drawn from a population with a standard

    asked on October 29, 2019
  58. math

    s the following relation a function? two ovals, one labeled x and the other labeled y. The negative 2 in the x oval is pointing to the 3 in the y oval, the 0 in x i

    asked on October 29, 2019
  59. math

    Two friends are playing a variation of MasterMind where one friend tries to guess the three digit number that the other friend is thinking of. The rules of the game are as follows: -Digits can be repeated -Zero cannot be the first number, but zero can be

    asked on February 14, 2019
  60. health/science

    what does the muscular system allow our bones to do

    asked on February 4, 2019
  61. math

    I am thinking of a four digit number. The sum of the four digits is 6, but none of the digits is zero. If you have only one opportunity to guess the number, what is the probability that your guess is correct?

    asked on January 21, 2019
  62. math

    Guests at a winter-themed party were served snowball cookies, snowman cookies, and snowflake cookies. All of the guests who ate snowball cookies also ate snowman cookies. Three-fourths of the snowball eaters did not also eat snowflake cookies. There were

    asked on December 20, 2018
  63. math

    Guests at a winter-themed party were served snowball cookies, snowman cookies, and snowflake cookies. All of the guests who ate snowball cookies also ate snowman cookies. Three-fourths of the snowball eaters did not also eat snowflake cookies. There were

    asked on December 19, 2018
  64. Finaance

    E.I. du Pont de Nemours & Co. has an issue of $4.50 preferred stock outstanding. It is currently selling for $108. What rate of return are investors requiring?

    asked on December 7, 2018
  65. chemistry

    If not all the alum dissolves in the water before adding the Ba(NO3)2 solution, what effect will this have on the sulfate percent error determination?

    asked on November 4, 2018
  66. Chemistry

    A calorimeter, with calorimeter constant 7.31 J K–1, was used to measure the heat of reaction for mixing 100.0 mL of 0.100 M Ag+ with 100.0 mL of 0.100 M Cl–. The temperature change was +0.770 K for the 200.0 g of solution (specific heat capacity =

    asked on November 21, 2017
  67. Chemistry

    At 20.0°C the vapour pressure of pure methanol is 11.8 kPa and that of pure ethanol is 5.93 kPa. A gaseous mixture of methanol and ethanol is cooled and compressed until the first drops of liquid form at 20.0°C and a total pressure of 10.0 kPa. Assuming

    asked on November 21, 2017
  68. Maths

    A sum of rs400 amounts to rs480 in 4years. What will it amount to if the rate of interest is increased by 2% p.a

    asked on October 23, 2017
  69. Physics

    Excellent human jumpers can leap straight up to a height of 100 cm off the ground. To reach this height, with what speed would a person need to leave the ground?

    asked on October 15, 2017
  70. chemistry

    Write the oxidation and reduction half-reactions for a silver-chromium voltaic cell. Identify the anode, cathode, and the direction of electron flow. Ag+ + e-  Ag Cr  Cr2+ + 2e- or Cr  Cr3+ + 3e- ????? Which is the correct equation for the

    asked on June 16, 2016
  71. Physics

    determine the point of zero gravitation force, as measured from the centre of earth (mass 5.97 x 10^24 kg) to the sun ( mass 1.99 x 10^30 kg) if the earth-sun distance is 150 x 10^6 km.

    asked on February 13, 2016
  72. Physics

    a 1.2 kg magnet is capable of holding up a 0.5 kg mass. the magnet is placed on a vertical refrigerator door and given an initial push so that it slides up the door with an initial velocity of 0.11 m/s. if the coefficient of kinetic friction between the

    asked on February 13, 2016
  73. Physics

    A tennis player strikes a ball when it is 2.20m above the ground, with a velocity 18.7 m/s at 20 degrees above the horizontal. The net is 5m away horizontally and it is 0.90m high. after 0.37 seconds, what is the direction of the ball with respect to the

    asked on January 28, 2016
  74. statistics help

    Tests on a Chevy Cobalt incdicate a population mean of 32 mpg and a population standard deviation of 3.5 mpg. You take an SRS (sample random sample) of 10 cars to get a sample mean. What is the probability that your sample mean is greater than 34 mpg? I am

    asked on December 8, 2015
  75. Chemistry

    3. Choose the hybridization schemes for the following species. (a) AsBr6− sp sp2 sp3 sp3d sp3d2 (b) CSe2 sp sp2 sp3 sp3d sp3d2 (c) PbCl4 sp sp2 sp3 sp3d sp3d2 (d) SeO32− sp sp3 sp2 sp3d sp3d2 (e) BiF5 sp sp2 sp3 sp3d sp3d2

    asked on December 7, 2015
  76. Chemistry

    1. [ PF4 ]+ (a) What is the electron-group geometry, according to VSEPR theory? (b) What is the molecular geometry? (c) Is this species polar or nonpolar?

    asked on December 7, 2015
  77. math

    verify sin0/sin0+cos0=tan0/1+tan0

    asked on December 3, 2015

    A dock worker is loading a 25 kg solid cylindrical barrel to a ship by rolling it up a 9 meter long and 1.5 meter high ramp. At the top of the ramp the dock worker stop to go around the barrel but he loses the grip and the barrel starts to roll down the

    asked on April 8, 2015
  79. chemisty

    The initial concentration of NO2 in a closed container is 0.750M. At equilibrium the concentration of O2 is 0.125M. What are the concentrations of NO2 and NO at equilibrium? 2NO2 (aq) ==== 2NO (aq) + O2 (aq)

    asked on March 1, 2015
  80. chemistry

    The Henry’s Law constant for N2 in water at 30 oC is 6.0 x 10-4 M/atm, calculate the solubility of nitrogen gas in water at a partial pressure of 2.5 atm

    asked on February 5, 2015
  81. physics

    Two geological field teams are working in a remote area. A global positioning system (GPS) tracker at their base camp shows the location of the first team as 43 km away, 23° north of west, and the second team as 29 km away, 33° east of north. When the

    asked on January 15, 2015
  82. physics

    A 70.3-kg person puts on a life jacket, jumps into the water, and floats. The jacket has a volume of 3.07 x 10-2 m3 and is completely submerged under the water. The volume of the person's body that is underwater is 6.49 x 10-2 m3. What is the density of

    asked on November 16, 2014
  83. physics

    Car A uses tires for which the coefficient of static friction is 0.333 on a particular unbanked curve. The maximum speed at which the car can negotiate this curve is 13.8 m/s. Car B uses tires for which the coefficient of static friction is 0.843 on the

    asked on October 20, 2014
  84. physics

    A 2.20-kg ball, moving to the right at a velocity of +1.27 m/s on a frictionless table, collides head-on with a stationary 7.20-kg ball. Find the final velocities of (a) the 2.20-kg ball and of (b) the 7.20-kg ball if the collision is elastic. (c) Find the

    asked on October 12, 2014
  85. physics

    A rocket blasts off from rest and attains a speed of 59.4 m/s in 14.1 s. An astronaut has a mass of 66.7 kg. What is the astronaut's apparent weight during takeoff?

    asked on September 30, 2014
  86. physics

    The depth of the ocean is sometimes measured in fathoms (1 fathom = 6 feet). Distance on the surface of the ocean is sometimes measured in nautical miles (1 nautical mile = 6076 feet). The water beneath a surface rectangle 3.70 nautical miles by 2.80

    asked on September 13, 2014
  87. physics

    The depth of the ocean is sometimes measured in fathoms (1 fathom = 6 feet). Distance on the surface of the ocean is sometimes measured in nautical miles (1 nautical mile = 6076 feet). The water beneath a surface rectangle 3.70 nautical miles by 2.80

    asked on September 13, 2014
  88. Maths

    1. What is the Right Riemann Sum for f(x)=x−3 over the interval [8,11], with n=3 rectangles of equal width? 2. What is the right Riemann sum of f(x)=x+3 when using 3 rectangles in the range [−3,−1]? 3. What is the left Riemann sum of f(x)=−2x+1

    asked on June 1, 2014
  89. Language Arts

    *Trying to laugh as quietly as possible*, Lucas snuck out of the kitchen. A. Prepositional phrase B. Gerund phrase C. Participial phrase D. Appositive phrase Hello I was wondering if my answer is correct for this question, the answer I choose was C.

    asked on January 14, 2014
  90. Chemistry

    Convert the concentration of CoCl2 from 22.0 mg/mL into molarity.

    asked on October 6, 2013
  91. Geometry

    Use the given plan to write a two-column proof of the Symmetric Property of Congruence. Given: segment AB ≅ segment EF Prove: segment EF ≅ segment AB Plan: Use the definition of congruent segments to write segment AB ≅ segment EF as a statement of

    asked on September 17, 2013
  92. physics

    Suppose we ran m steps of Grover's algorithm on some function f (which has one marked element y) and the resulting superposition was exactly |y⟩. If we run for m+1 additional steps (i.e. total of 2m+1 steps from the initial state), what is the resulting

    asked on April 19, 2013
  93. chemistry

    Which of the following statements describes why ion exchange of 99% SiO2 - 1% B2O3 in a salt bath of molten postassium chloride (KCl) is not an effective way to increase the surface strength of the glass sample? The ion exchange works correctly, however

    asked on April 13, 2013
  94. Biology

    The body of multicellular animals (salamanders, frogs and so on) is made of more than hundred different kinds of somatic cells. Even though they’re so different, they all have the same genome (the same DNA, the same set of genes). This is called genomic

    asked on April 12, 2013
  95. physics

    Alice has a very important piece of information, which is encoded as an integer k. She is storing this number in a quantum state |ψ⟩=∑xαx|x⟩ of n qubits in such a way that if you apply QFT2n to |ψ⟩ and then measure in the standard basis, you get

    asked on March 22, 2013
  96. physics

    n this problem, we will carry out some steps of the quantum factoring algorithm for N=15. (a) What is the period k of the periodic superposition set up by the quantum factoring algorithm if it chooses x=2? (b) Assume that we found this k using period

    asked on March 22, 2013
  97. physics

    Let |α⟩=1M√∑M−1j=0αj|j⟩ and let |β⟩=1M√∑M−1j=0βj|j⟩ be its QFTM. Suppose we shift the superposition |α⟩ to produce |α′⟩=1M√∑M−1j=0αj|j+1(modM)⟩, and let |β′⟩=1M√∑M−1j=0βj′|j⟩ be the QFTM of

    asked on March 20, 2013
  98. physics

    A capacitor consists of two concentric spherical shells. The outer radius of the inner shell is a=0.76 mm and the inner radius of the outer shell is b=3.31 mm . (a) What is the capacitance C of this capacitor? Express your answer in Farads. unanswered (b)

    asked on March 6, 2013
  99. physics

    Suppose H⊗3|ϕ⟩=12√(|000⟩+|111⟩). What is |ϕ⟩? Specify the probability amplitude for each component:

    asked on March 6, 2013
  100. physics

    Suppose we have two qubits in the state (a|0⟩+b|1⟩)|0⟩, to which we apply the following circuit. (a) Is the resulting state entangled? Yes No (b) Specify the state of each qubit after we applied the circuit.

    asked on March 1, 2013


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