# brian

Popular questions and responses by brian
1. ## math Question

Find an equation that models a hyperbolic lens with a=12 inches and foci that are 30 inches apart. assume that the center of the hyperbola is the origin and the transverse axis is vertical.

2. ## calculus

At a sand and gravel plant, sand is falling off a conveyor and onto a conical pile at the rate of 10 cubic feet per minute. The diameter of the base of the cone is approx­ imately three times the altitude. At what rate is the height of the pile changing

3. ## math/statistics

In the Numbers Game, a state lottery, four numbers are drawn with replacement from an urn containing balls numbered 0-9, inclusive. Find the probability that a ticket holder has the indicated winning ticket. The first three digits in exact order.

4. ## Chemistry

Which element listed should have chemical properties similar to fluorine (F) A.Li B.Si C.Br D.Ne Br, along with F, a halogen (column 7 of the periodic table) Look at the periodic table. The columns are called groups. Elements in the same group have similar

5. ## Chem

what kind of intermolec forces are in NH4Cl i thought it was london dispersion, dipole dipole, and hydrogen bonding and nottttt ionic. what am i doing wrong?

6. ## Math

Postal regulations specify that a parcel sent by priority mail may have a combined length and girth of no more than 96 in. Find the dimensions of a rectangular package that has a square cross section and the largest volume that may be sent via priority

7. ## Bus. Math 123

Problem: Invoice-Nov. 27. Date goods recvd. ? Terms- 2/10 EOM. Last day of discount- ? Final day bill is due ? Complete above.

8. ## algebra

translate into algebraic expression 24 more than twice Greg's age

Charges of −4q are fixed to diagonally opposite corners of a square. A charge of + 5q is fixed to one of the remaining corners, and a charge of + 3q is fixed to the last corner. Assuming that ten electric field lines emerge from the + 5q charge, sketch

10. ## Calculus I, differentiation

The number, N, of people who have heard a rumor spread by mass media by time, t, is given by N(t)=a(1−e−kt). There are 6 million people in the population, who hear the rumor eventually. If 5% of them heard it on the first day, find the percentage of

11. ## Drug Abuse and Addiction

I need research sources for drug abuse and addiction. Thank you. Check these sources -- http://www.nida.nih.gov/ http://teens.drugabuse.gov/ (Broken Link Removed) http://www.drugabusestatistics.samhsa.gov/

12. ## MATH

A photograph has been enlarged to three times its previous size. By what percentage has the size of the photograph increased?

13. ## Calc I

if f(t)=sqrt(4t+1) find f''(2) I got the first derivative to be: 1/2(4t-1)^-1/2 * 4t^3 and i'm trying to figure out if i need the product rule again to find the second derivative -1t^3(4t-1)^-3/2 * 4t^3 The answer if -4/27 and I'm not sure how to get that

14. ## Math

One model of Earth's population growth is , where t is measured in years since 1990, and P is measured in billions of people. Which of the following statements are true?

15. ## Statistics

A random sample of forty-eight 200 meter swims has a mean of 3:12 minutes and a standard deviation of .09 minute. Construct a 95% confidence interval for the population mean time. I know u: 3.12, sx: .09, n:48, c:.95 What is the formula I use to find the

16. ## AP CHEM

Complete and balance the reaction Al(s) + Pb2+(aq) ! using the smallest possible integers. I got: 2Al(s) + 3Pb2 ==> Al2Pb3 Calculate the standard free energy. Faraday’s constant is 96485 J V · mol Answer in units of kJ/mol. I know the formula is -nFE

17. ## Calculus II

A cable that weighs 1.5 lb/ft is used to lift 700 lb of coal up a mineshaft that is 400 ft deep. Find the work done.

18. ## Physics

How much work must be done to increase the speed of an electron (a) from 0.18c to 0.19c and (b) from 0.98c to 0.99c? Note that the speed increase is 0.01c in both cases.

19. ## English

Dragonwings by Laurence yep What conflict is left unresolved at the end?

20. ## physics

An object falls a distance h from rest. If it travels 0.45h in the last 1.00 s, find the time and the height of its fall.

21. ## Chemistry

A compound containing only carbon, hydrogen and oxygen is subjected to elemental analysis. Upon complete combustion, a .1804g sample of the compound produced .3051g of CO2 and .1249g of H2O. What is the empirical formula of the compound?

22. ## physics

a horizontal force of 290N is applied to a stationary wooden box in one direction, and a 800N horizontal force is applied in the opposite direction. What additional force is needed for the box to remain stationary?

23. ## statistics

A college professor decides to run for Congress in a district with 450,000 registered voters. In a survey she commissioned, 58% of the 4000 registered voters interviewed indicated that they plan to vote for her. The population of interest is the: A.

24. ## probability

For each exam, Ariadne studies with probability 1/2 and does not study with probability 1/2, independently of any other exams. On any exam for which she has not studied, she still has a 0.20 probability of passing, independently of whatever happens on

25. ## Algerbra 1

The Quotient of 6 times a number and 16 ? "Quotient" is what we call the result of a division, the result of multiplication is called a product. You used the word "times" which shows multiplication. BTW, I refuse to tell you what 6 times 16 is.

26. ## Math

A man left of his estate in Kerugoya to his wife and his two sons. The remainder was to be shared equally among his six brothers. If the estate was worth Sh 3456000, how much did each of those people get?

27. ## english

15. Identify the sentence in which the underlined pronoun is used incorrectly. There are only six days left in the school year. It will be fun to visit their house in the summer. Their just going to have to wait to see the movie. Greg refused to go there

28. ## Chemistry

What is the C-C-H bond angle in the molecule H2CCO?

29. ## Physics

We want to rotate the direction of polarization of a beam of polarized light through 90 degrees by sending the beam through one or more polarizing sheets.(a) What is the mini-mum number of sheets required? (b) What is the minimum number of sheets required

30. ## science

a person weighs 815 N on the earth, what is the persons weight on the moon?

31. ## Accounting

It is stand accounting procedures, or GAAP, to make an adjusting entry to remove the current year’s principle from the long-term liabilities. This entry reduces the long-term liabilities and increases the current liabilities. You are the bookkeeper for

32. ## programming

create the logic for a program that calculates and displays the amount of money you would have if you invested \$5000 at 2 percent simple interest for one year. create a separate method to do the calculation and return the result to be displayed.

33. ## Algebra

A rectangular Persian carpet has a perimeter of 212 inches. The length of the carpet is 24 inches more than the width. What are the dimensions of the carpet?

34. ## health

Identify at least five indicators of project failure that manifest themselves in this case study. Are these right ? these are a few i have came up with: organized inertia lack of clarity of pupose lack of landor project status report insufficient

35. ## Math

In a game, 5 points are awarded for each game and 2 points are deducted for each game lost,Kyler attempted 15 games,if he got 68 points,how many gamesvdid he lose?

36. ## math

The difference between two numbers is 3. Eight times the larger number is 10 times the smaller number. Write a system of equations describing the given conditions. Then solve the system by the substitution method and find the two numbers.

37. ## Precalculus

Every point in the plane has exactly two polar coordinates. A)The statement is true because every point in the plane has a unique polar representation. B)The statement is false because left parenthesis r comma theta right parenthesis equals left

38. ## Calculus

A spherical balloon is inflated with gas at the rate of 20 cubic feet per minute. How fast is the radius of the balloon increasing at the instant the radius is (a) 1 foot and (b) 2 feet?

39. ## statistics

A simple random sample of students is selected, and the students are asked how much time they spent preparing for a test. The times (in hours) are as follows: 1.3 7.2 4.2 12.5 6.6 2.5 5.5 Based on these results, a confidence interval for the population

40. ## Pre-Calculus

How do I solve the equation: 3 = 2.1 sin[(pi/6)t - 5pi/6] + 3.2

41. ## Chemistry

Explain how a person bailing out a row boat with a leak could represent a state of physical equilibrium.

42. ## social studies

Which of the following statements about the natural resources of the United States is most accurate? A. The many agricultural resources of the United States have made up for its lack of other resources. B. U.S. industry and agriculture have prospered

43. ## math

Use the formula t = (0.25) s1/2 to find the time t in seconds it will take a stone to drop a distance s of 200 feet. Round your answer to the nearest tenth of a second.

44. ## Physics

Betty weighs 427 N and she is sitting on a playground swing seat that hangs 0.22 m above the ground. Tom pulls the swing back and releases it when the seat is 0.88 m above the ground. The acceleration of gravity is 9.8 m/s2. How fast is Betty moving when

45. ## physics

is the force exerted by the wall on the person’s hand passive or active?

46. ## Math

Where do the parentheses go in this equation? 8+3x6-4-1=13?

47. ## math

when might you think you're built upside down?

48. ## toxicology- can someone re work this question?

Hi, I have to answer this question "why do we say that metabolism is the factor that most accounts for differences among species in the toxicity of some xenobiotics? I don't understand what the question means- I understand all the words in the question,

49. ## sociology

What is the best way to characterize the health care that the poor receive? inferior superior because of government insurance the same as care for wealthy people inferior only for the elderly poor about the same as for the average American

50. ## probability

When you enter your bank, you find that there are only two tellers, both busy serving other customers, and that there are no other customers in line. Assume that the service times for you and for each of the customers being served are independent

51. ## calculus

A patrol car is parked 50 feet from a long warehouse The light on the car turns at a rate of 30 revolutions per minute. How fast is the light beam moving along the wall when the beam makes the fol­ lowing angles with the line perpendicular from the light

52. ## Calculus

All edges of a cube are expanding at the rate of 3 centimeters per second. How fast is the volume chang­ ing when each edge is (a) 1 centimeter and (b) 10 centimeters?

53. ## Math

The length of a rectangular board is 10 cm longer than its width. The width of the board is 26 cm. the board is cut into 9 equal pieces. What is the area of each piece? What are the possible dimensions of each piece?

54. ## Chemistry (Electrochemistry)

The standard potential for the following galvanic cell is 1.72V : Be(s)|Be2+(aq)||Pb2+(aq)|Pb(s) The standard reduction potential for the Pb2+/Pb half-cell: E = -.13V Calculate the standard reduction potential for the Be2+/Be half-cell. What I know: Be is

55. ## Chemistry, HELP!!

a) If the volume of a flask is 165 mL and the mass of the vapor in the flask is 0.2136 grams, what is the density of vapor in the flask? b)If the temperature of the vapor is 25 degrees Celsius, what is the molecular weight of the vapor? (Assume the gas

56. ## Physics

A 0.075 kg ball in a kinetic sculpture moves at a constant speed along a motorized conveyor belt. The ball rises 1.32 m above the ground. A constant frictional force of 0.350 N acts in the direction opposite the conveyor belt's motion. What is the net work

57. ## calculus

Find dy/dx by implicit differentiation. sin x = x (1 + tan y)

58. ## physics

A 24- kg monkey climbs up a massless rope that runs over a frictionless tree limb and back down to a 35- kg package on the ground. What is the magnitude of the least acceleration the monkey must have if it is to lift the package off the ground?

59. ## physics

During a rockslide, a 520kg rock slides from rest down a hillside that is 500m long and 300m high. The coefficient of kinetic energy between the rock and the hill surface is .25. a) If the GPE energy U of the rock –Earth system is zero at the bottom of

60. ## science

why do dry sodium chloride, the solutions of sodium nitrate and solution chloride all impart the same color to the flame?

61. ## probability

1. Busy people arrive at the park according to a Poisson process with rate λ1=3/hour and stay in the park for exactly 1/6 of an hour. Relaxed people arrive at the park according to a Poisson process with rate λ2=2/hour and stay in the park for exactly

62. ## math

A financier plans to invest up to \$500,000 in two projects. Project A yields a return of 8% on the investment of x dollars, whereas Project B yields a return of 13% on the investment of y dollars. Because the investment in Project B is riskier than the

63. ## History

Which adjective best describes Ming China’s position toward European trade? a.diplomatic b.equivalent c.inviting d.restrictive

64. ## calculus

Cars on a certain roadway travel on a circular arc of radius r. In order not to rely on friction alone to over­ come the centrifugal force, the road is banked at an angle of magnitude 0 from the horizontal. The banking angle must satisfy the equation rg

65. ## calclus

A fish is reeled in at a rate of 1 foot per second from a bridge 15 feet above the water. At what rate is the angle between the line and the water changing when 25 feet of line is out? (Assume the fish stays near the surface of the water.)

66. ## Math

Prove that an exterior angle of a triangle is equal to the sum of the non adjacent interior angles of that triangle. Use the following variables in your proof. Exterior angle=w Interior adjacent angle= x Interior non adjacent angle1= y Interior non

67. ## statistics

Use the given sorted values below which are the numbers of points scored in the Super Bowl for a recent period of 24 years. 36 37 37 39 39 41 43 44 44 47 50 53 54 55 56 56 57 59 61 61 65 69 69 75

68. ## macroeconomics

b. Now suppose that the gross national debt initially is equal to \$2.5 trillion and the federal government then runs a deficit of \$100 billion: i. What is the new level of gross national debt? ii. If 100 percent of the deficit is financed by the sale of

69. ## Physics

We want to rotate the direction of polarization of a beam of polarized light through 90 degrees by sending the beam through one or more polarizing sheets. (a) What is the mini-mum number of sheets required? (b) What is the minimum number of sheets required

70. ## Physics

A 5.00-grain aspirin tablet has a mass of 320 mg. For how many kilometers would the energy equivalent of this mass power an automobile? Assume 12.75 km/L and a heat of combustion of 3.65x10^7 J/L for the gasoline used in the automobile.

71. ## Physics

A 34-g bullet traveling at 120m/s embeds itself in a wooden block on a smooth surface. The block then slides toward a spring and collides with it. The block compresses the spring (k=100 N/m) a maximum of 1.25 cm. Calculate the mass of the block of wood.

72. ## Physics

A guy playing basket-ball needs to make the penalty shot for his team to win. Given that the ball is thrown from a height of 2 meters at an angle of 60 degrees, that the post is situated at a distance of 7 m and standing at 3.5 m: a) What does the initial

73. ## physics

A large box whose mass is 20 kg rests on a frinctionless floor. A mover pushes on the box with a force of 250 N at an angle of 35 degrees below the horizontal. What is the acceleration of the box across the floor?

74. ## Math

How can the faces of two cubes be numbered so that when they are rolled, the resulting sum is a number 1 to 12 inclusive and each sum has the same probability?

75. ## Chemistry

How many molecules of Cl2 would be formed from the reaction mixture that produces the greatest amount of products? Consider the following reaction: 4HCl(g)+ O2(g)to 2H2O +2Cl2(g)

76. ## Finance

You have just won the lottery and will receive \$1,000,000 in one year. You will receive payments for 30 years, which will increase 5 percent per year. The appropriate discount rate is 8 percent. What is the present value of your winnings?

77. ## MATH

The triangular numbers are the numbers 1, 3, 6, 10, 15, . . .; the square numbers are the numbers 1, 4, 9, 16, 25, . . . The pentagonal numbers 1, 5, 12, 22, 35, . . .. The geometrical language is justified by the following diagrams: a. What are the first

78. ## AP Physics

Assume that at sea-level the air pressure is 1.0 atm and the air density is 1.3 kg/m3. (a) What would be the height of the atmosphere if the air density were constant? 7.919 km (b) What would be the height of the atmosphere if the air density decreased

79. ## Physics

Two masses of 4.25 kg each, connected by a string, slide down a ramp making an angle of 44° with the horizontal. The coefficient of kinetic friction between m1 and the ramp is 0.31. The coefficient of kinetic friction between m2 and the ramp is 0.12. Find

80. ## Trigonometry

How would you find the solutions to this problem? (cosx)(cscx)=2cosx

81. ## Physics

A 0.165kg cue ball with an inital speed of 2 m/s bounces off the rail in a game of pool. For x and y axses located the counce reverses the y component of the ball's velocity but does not alter the x component(the angle is 30 in the negative x axis and it

82. ## physics

Approximately 5.5 X10^6 kg of water fall 50m over Niagara Falls each second. a) What is the decrease in the gravitational potential energy of the water-Earth system each second? b) If all this energy could be converted to electrical energy (can’t happen)

83. ## Mathematics

In a shool,7/10 of the pupils like mathematics.Half of those pupils who like mathematics are girls.If there areither 240 pupIlsley altogether in the school,how many girls like mathematics.

84. ## Physics

if a 250 g mass is placed at the 20 cm mark (30 cm from the fulcrum), at what mark should a 500 g mass be placed so that the system balances?

85. ## math

If BM bisects angle ABc, and Angle ABM = 2x + 10, angle MBC = x+22, angle MBD = 1/3(DBC), find the measure of angle ABD

86. ## health

Which one of the following groups has the highest incidence of diabetes in the U. S.? Hispanic Americans Native Americans Asian Americans White Americans I think it's white americans, but i'm not sure

87. ## MATH

Find and simplify the diﬀerence quotient for the given function. f(x)= -x^2+2x-1 I need to know how to set up the equations and simplify everything when dividing by h at the end.

88. ## Math

a rectangular prism 3cm x 5cm x 6cm is painted and is then cut into 1cm^3 cubes. What is the total unpainted surface area of these cubes? - Please help! I do not understand this question.

89. ## Science - chemistry

Write the complete ionic equation for the reaction of magnesium phosphate with lead (II) nitrate. Include which ions will be aqueous and which compound will precipitate. (Valences: Mg=+2, PO4=-3, Pb=+2, NO3=-1)

90. ## math

A financier plans to invest up to \$500,000 in two projects. Project A yields a return of 8% on the investment of x dollars, whereas Project B yields a return of 13% on the investment of y dollars. Because the investment in Project B is riskier than the

91. ## math

A company manufactures x units of Product A and y units of Product B, on two machines, I and II. It has been determined that the company will realize a profit of \$2/unit of Product A and a profit of \$7/unit of Product B. To manufacture a unit of Product A

92. ## Physics

A ball with mass m=1kg and speed vo=5m/sec elastically collides with a stationary, identical ball (all resting on a frictionless surface so gravity is irrelevant). A student measures the top ball emerging from the collision at at speed vt=4m/sec at an

93. ## Calclus

A point is moving along the graph of y = 1/(1 + x^2) so that dxldt = 2 centimeters per minute. Find dy/dt for the following values of x. (a) X = -2

94. ## Math

A 2-digit number is twice the difference of its digits. What is the number?

95. ## Calculus

Evaluate as limit approaches 0. (Without using l'hopital's rule. ( Sqrt(4+sin(x))-2 ) / (3x)

96. ## science

A bullet of 29g is shot from a gun of mass 20kg with a muzzle velocity of 200ms if the bullet is 30cm long.determine. a)acceleration of the bullet b)the recoil velocity of the gun

97. ## physics

4. A gun’s bullet was launched horizontally with a speed 600m/s. It fell to the ground 300m away from the gun. a. How long was the bullets flight? b. At what height was the gun’s barrel at the moment of the shot? 5.

98. ## physical science

A golfer on a level fairway hits a ball at an angle of 38° to the horizontal that travels 85 yd before striking the ground. He then hits another ball from the same spot with the same speed, but at a different angle. This ball also travels 85 yd. At what