rick

Most popular questions and responses by rick
1. Statistics

According to the Pew Internet &American Life Project. 75% of American adults use the internet. The Pew project authors also peported on the percentage of Americans who use the internet by age group. The data in the in the agefile group was consistent with

2. Algebra

The Oliver Company plans to market a new product. Based on its market studies, Oliver estimates that it can sell up to 4,500 units in 2005. The selling price will be \$2 per unit. Variable costs are estimated to be 20% of total revenue. Fixed costs are

3. Phyiscs

A man claims he can safely hold on to a 9.7-kg child in a head-on collision with a relative speed of 112-mi/h lasting for 0.12 s as long as he has his seat belt on. (a) Find the magnitude of the average force needed to hold onto the child. HELP

4. Math

Find the length of the curve r(t)=sqrt(2)ti + e^tj + e^-tk, 0

5. Maths

An aeroplane is flying horizontally directly towards the city at an altitude of 400 metres. At a given time the pilot views the city lights of Melbourne at an angle of depression of 1.5 degrees. Two minutes later the angle of depression of the city lights

6. Physics

A force vector F of magnitude 12N is applied to a FedEx box of mass m2=1kg. The force is directed up a plane tilted by theta=37 degrees. The box is connected by a cord to a UPS box of mass m1=3kg on the floor. The floor, plane, and pulley are frictionless,

7. Chem II

2.5 mol NOCl(g) was placed in a 2.50 L reaction vessel at 400 degrees C. After equilibrium was established, it was found that 28% of the NOCl had dissociated according to the equation: 2NOCl(g)2NO(g)+Cl2(g) Calculate the equilibrium constant, Kc, for the

8. Chemistry

What volume of 0.716M KBr solution is needed to provide 10.5g of kBr?

9. math

The average middle-distance runner at a local high school runs the mile in 4.5 minutes, with a standard deviation of 0.3 minute. The percentage of a runners that will run the mile in less than 4 minutes is %.

10. english 1

What is one way that “The Maori: Genealogies and Origins in New Zealand” contrasts with “The Raven and the First Men: The Beginnings of the Haida”?

11. math

a model rocket is projected straight upward from the ground level. It is fired with an initial velocity of 192 ft/s. How high is the rocket after 10 seconds? When is the rocket at a height of 432 feet? What is the maximum height of the rocket? When will

12. Chemistry

A 5.00 mL aliquot of vinegar (acetic acid, FW = 63 g/mol) was diluted and titrated with 0.1104 M NaOH requiring 32.88 mL. If the vinegar has a density of 1.055 g/mL, calculate its acidity as % acetic acid

13. Pre-Cal

This exercise is based on the following table, which lists interest rates on long-term investments (based on 10-year government bonds) in several countries in 2008. Assuming that you invest \$12,000 in the Japan(1.5%), how long (to the nearest year) must

14. physics

A ball is thrown 107 m upward and then falls back to earth. Neglecting air resistance, how long will it be in the air? The acceleration of gravity is 9.8 m/s2 . Answer in units of s

15. physics

A piece of copper wire has a resistance per unit length of 6.45*10-3 /m. The wire is wound into a thin, flat coil of many turns that has a radius of 0.140 m. The ends of the wire are connected to a 12.0 V battery. Find the magnetic field strength at the

16. physics

A law enforcement officer in an intergalactic "police car" turns on a red flashing light and sees it generate a flash every 1.5 s. A person on earth measures that the time between flashes is 2.9 s. How fast is the "police car" moving relative to the earth?

17. Physics

A 1kg pigeon sits on the middle of a clothesline whose supports are 10m apart. The clothesline sags by 1 meter. If the weight of the clothesline is negligible, find the tension in it.

18. physics question

A spacecraft in the shape of a long cylinder has a length of 100 m, and its mass with occupants is 1660 kg. It has strayed too close to a black hole having a mass 103 times that of the Sun (Msun = 1.99 x 1030 kg). The nose of the spacecraft points toward

19. chemistry

propanoic acid ch3ch2cooh is a weak acid which has a value for dissociation content of ka = 6.3 x 10^-6 calculate the pH of an aqueous solution of propanoic acid containing 37 g of propanoic acid per litre. i'm stumbled on this one.. i calculated that the

20. Maths

A movie theatre seats 200 people. For any particular show, the amount of money, m, the theatre makes is a function of the number of people, n, in attendance. If a ticket costs \$12 and the cost to the theatre to run one show is \$120, state the domain and

21. physics

In astronomy, distances are often expressed in light-years. One light-year is the distance traveled by light in one year. The distance to Alpha Centauri, the closest star other than our own sun that can be seen by the naked eye, is 4.7 light-years. Express

22. English

A question from Sir Knight and the Green Knight After the Green Knight addresses King Arthur and his Knights, King Arthur says, "By Heaven, Sir, your request is strange". What is the Green Knight's request?

23. Physics

A 1kg pigeon sits on the middle of a clothesline whose supports are 10m apart. The clothesline sags by 1 meter. If the weight of the clothesline is negligible, find the tension in it.

24. physics

A projectile is shot straight up from the earth's surface at a speed of 1.50×104 .

25. Chemistry(URGENT!)

determine whether the following salts will form acidic, neutral or basic solutions in water. Na2HPO4 CaNO2 NH4CH3COO Al2SO4 NaF Please, i need the answer to this question within 2 hours of when i post this!

26. trig

Use half-angle formulas to find the exact value for the following cot 75 degrees

27. physics

An electric power line carries a current of 1600 A in a location where the earth's magnetic field is 4.0*10-5 T. The line makes an angle of 75° with respect to the field. Determine the magnitude of the magnetic force on a 130 m length of line.

28. physics

The human eye is most sensitive to light having a frequency of about 5.3*10^14 Hz, which is in the yellow-green region of the electromagnetic spectrum. How many wavelengths of this light can fit across the width of your thumb, a distance of about 2.0 cm?

29. Chemistry

I'm having trouble with the following question, any help would be greatly appreciated. A voltaic cell consists of a Zn/Zn^2+ half-cell and a Ni/Ni^2+ half-cell at 25 C . The initial concentrations of Ni^2+ and Zn^2+ are 1.30 M and 0.100 M , respectively.

30. physics

A person stands 4.4 m in front of a wall that is covered floor-to-ceiling with a plane mirror. His eyes are 1.9 m above the floor. He holds a flashlight between his feet and manages to point it at the mirror. At what angle of incidence must the light

31. physics

A box slides down a frictionless 35 degree incline. Determine its acceleration. If the incline is 10.0 m long and the box starts from rest, how much time does it take to get to the bottom?

32. physics

an electron is accelerated from rest through a potential difference V. If the electron reaches a speed of 9.11*x10^6 m/s, what is the potential difference?

33. Physics

A man lies on a plank of negligible mass supported by two scales 2.50 m apart. His head rests on the left scale which is also the axis of rotation. If the left scale reads 290 N and the right scale reads 122 N calculate his mass.

34. physics

The average power dissipated in a stereo speaker is 54 W. Assuming that the speaker can be treated as a 4.0- resistance, find the peak value of the ac voltage applied to the speaker.

35. physics

A car at the Indianapolis-500 accelerates uniformly from the pit area, going from rest to 320 km/h in a semicircular arc with a radius of 190 m. 1.) Determine the tangential acceleration of the car when it is halfway through the turn, assuming constant

36. Chemistry

1)Which thermochemical equation and data does not agree with the other two written? a) 2NO (g)+ O2 (g) ->2 NO2 (g) deltaH=-169.8 b) NO (g) + 1/2 O2 (g) -> NO2 (g) delta H = -56.6 c) 4 NO2 (g) -> 4 NO (g) + 2 O2 (g) delta H = +226.4 d)all three equations

37. math

Is 499.79 million = 499,790,000? Is 15,099 million = 15,099,000,000?

38. Algebra

Find a linear equation whose graph is the straight line with the given property. HINT [See Example 2.] Through (2, −3) and (1, 1) Which formula do I use? y2-y1/x2-x1 or y-y1=m(x-x1)[

39. physics

An owl has good night vision because its eyes can detect a light intensity as small as 5.0*10^-13 W/m2. What is the minimum number of photons per second that an owl eye can detect if its pupil has a diameter of 7.0 mm and the light has a wavelength of 545

40. Physics

A wire with cross sectional area 1.00 cm2 stretches 0.500% of its length when it is stretched with a tension of 20.0 N. What is the Young's modulus of this wire?

41. math

4. A tree stands vertically on top of a hill whose angle of inclination is 30°. The top and base of the tree are 4√3 and 4 meters, respectively, from a point P at the foot of the hill. What is the angle of subtended by the tree at point P?

42. trig

If cos A =1/3 with A in QIV find cscA/2

43. Physics

How many electrons must be removed from an electrically neutral silver dollar to give it a charge of +2.8 µC?

44. Pseudocode programming

I need a currency conversion application. It does not have to be written in an actual programming language, just the pseudocode as well as the elements listed below. Complete requirements analysis Design Verification Validation and test documentation The

45. physics

A 3Kg projectile is fired straight upward from earth's surface with a speed that is one-fourth the escape speed. Neglecting air resistance. a) What is the Kinetic energy of this projectile when it is launched? b) what is the gravitational potential energy

47. Pre-Cal

This exercise is based on the following table, which lists interest rates on long-term investments (based on 10-year government bonds) in several countries in 2008. How long, to the nearest year, will it take an investment in Germany(4.3%) to triple its

48. chemistry

a sample of a radioisotope had a mass of 100.0 grams. After exactly 24 days, 6.25 grams remained. The half life of the isotope is _________

49. Calculus

400 feet of fencing is to be used to enclose four adjacent pieces of land. What dimensions will produce the largest area?

50. Physics

Vector A has a magnitude 12m and is angled at 60 degrees counterclockwise from the positive direction of the x axis of an xy coord. system. Also. Vector B = (12m)i + (8m)j on that same coord system. Rotate the system counterclockwise about the origin by 20

51. history

What did George Washington and Thomas Jefferson contribute in establishing a stable government after the adoption of the Constitution? For Washington I have: 1) He became first president for 8 years 2) Proclamation of Neutrality protected Americans from

52. Math

A basket of goods and services representative of the CPI cost \$2750 when the CPI stood at 118.3. What did the basket of goods cost 10 years earlier, when the CPI was at 93.1? What was the overall percent inflation experienced by consumers for the entire

53. Physics

A space probe has two engines. Each generates the same amount of force when fired, and the directions of these forces can be independently adjusted. When the engines are fired simultaneously and each applies its force in the same direction, the probe,

54. Busniness Finance

I am having some difficulties with week four lab. The explanation for problem skips a step and I do not know how to get the answer. (Weighted average cost of capital). As a member of the Finance Department of Ranch Manufacturing, your supervisor has asked

55. college algebra

Kepler’s third law. According to Kepler’s third law of planetary motion, the ratio t^2/r^3 has the same value for every planet in our solar system. R is the average radius of the orbit of the planet measured in astronomical units (AU), and T is the

56. trig

If sin = -3/5 with A in QIV, find cos A/2

57. physics

The coil of a generator has a radius of 0.12 m. When this coil is unwound, the wire from which it is made has a length of 5.5 m. The magnetic field of the generator is 0.10 T, and the coil rotates at an angular speed of 25 rad/s. What is the peak emf of

58. physics

In a lightning bolt, 13 C of charge flows in a time of 1.5*10-3 s. Assuming that the lightning bolt can be represented as a long, straight line of current, what is the magnitude of the magnetic field at a distance of 29 m from the bolt?

59. science

tell me about science apparatus They are used in science. You need a much more specific question to get a useful answer. For instance: What is the Hoffman apparatus, and how is it used?

60. Maths

A square is transformed into a recatangle of perimeter 30 cm, by increasing one side by 3 cm and reducing the adjacent side by 2 cm. Find the length of the square's side.

61. Physics

A man (mass 120.5 kg) is canoeing with his friend (mass 81.6 kg). He had the only paddle but dropped it in the lake. It has drifted just out of his reach along the long axis of the canoe. His friend suggests that if they trade places he might be able to

62. marketing

The marketing manager at Massimino & McCarthy, a chain of retail stores that sells men's clothing, is reviewing marketing research data to try to determine if changes in marketing strategy are needed. Which of the following sources of data would be a

63. math

An architect is designing the floors for a hotel. Each floor is to be rectangular and is allotted 720 ft of security piping around walls outside the rooms. What dimensions of the atrium will allow an atrium at the bottom to have maximum area?

64. chemistry

A 114g sample of sucrose undergoes incomplete combustion according to the reaction C12H22011 + 5O2 ---> 4C + 6CO + 2CO2 + 11H2O using the chart of enthalpies of formation determine the enthalpy released by the sample i think that it is a simple enthalpy

65. trig

Prove the identity sin(3 pi /2 + x) + sin(3pi/2 -x) = -2cosx

66. physics

A toaster uses a Nichrome heating wire. When the toaster is turned on at 20°C, the initial current is 1.50 A. A few seconds later, the toaster warms up and the current has a value of 1.22 A. The average temperature coefficient of resistivity for Nichrome

67. physics

An electron and a proton are initially very far apart (effectively an infinite distance apart). They are then brought together to form a hydrogen atom, in which the electron orbits the proton at an average distance of 5.11 10-11m. What is EPEfinal -

68. math

a model rocket is projected straight upward from the ground level. It is fired with an initial velocity of 192 ft/s. How high is the rocket after 10 seconds?

69. chemistry

which metal react most vigorously? metals aluminum, copper, magnesium, lead, tin, zinc 1. which metal will react most quickly? 2. which will take the longest time to react? 3. which will react most vigorously and least vigorously? 4. list metals from order

70. geometry

I was assiged to a 20question assigment and Im having troubles with the following question: "Find the coordinates of the midpoint of a segment having the endpoints C(4,1) and D(-3,7). Then find the distance between the endpoints PLEASE HELP!!! Its due on

71. geometry

I"m stuck on this question "Rays PQ and QR ae perpendicular.Point S lies in the interior of angle PQR.If angle PQS!=4+7a and angle SQR=9+4a,find angle PQS and angle SQR. PLEASE HELP!!!!

72. Economics

I have a few questions, for my test coming up. Which of the following is most necessary for specialization among producers to take place? Free trade Monetary policy Competition Scarcity Which of the following best states the purpose of an import quota? To

73. math

how much money would have to be invested in an account at 3.98% annual interset to achieve a balance of 25,000 in 17 years if a. The account pays simple interest b. the account compound interest qrtly c. the account compounds interest continuously

74. psychology

Much research is being conducted on repairing faulty sensory organs through devices such as personal guidance systems and eyeglasses, among others. Do you think that researchers should attempt to improve normal sensory capabilities beyond their

75. Physics Help..

The cable of an elevator of mass M = 1900 kg snaps when the elevator is at rest at one of the floors of a skyscraper. At this point the elevator is a distance d = 10.6 m above a cushioning spring whose spring constant is k = 8500 N/m. A safety device

76. geometry

I'm stuck on this question please help. "Lines p and q intersect to form adjacent angles 1 and 2.If angle 1=3x+18 and angle 2=-8y-70,find the values of x and y so that p is perpendicular to q.

77. math

Circla all numbers in which the ones digit is twice the hundreds digit. 842 824 482 284 248 933 977 337 379

78. Physics

If a projectial is fired at such an angle that the vertical componet of its velocity is 49m/s. The horizonal componet of its velocity is 61m/s, then how long will the projectia stay in the air? What distance will it travel? And what is the inital speed?

79. Physics

If a projectial is fired at such an angle that the vertical componet of its velocity is 49m/s. The horizonal componet of its velocity is 61m/s, then how long will the projectia stay in the air?

80. physics

An electron and a positron each have a mass of 9.11*10^-31 kg. They collide and both vanish, with only electromagnetic radiation appearing after the collision. If each particle is moving at a speed of 0.55c relative to the laboratory before the collision,

81. physics

There is a 0.225 T magnetic field directed along the +x axis and a field of unknown magnitude along the +y axis. A particle carrying a charge of 7.20 10-5 C experiences a maximum force of 0.455 N when traveling at a speed of 2 104 m/s through the region

82. health

Which of the following is NOT a type of muscle? A. Skeletal B. Long C. Smooth D. Cardiac

83. algebra

Draw a rectangle to show that 5 (x + 2 ) and 5x + 10 are equivalent ?

Need help to explain to my daughter: A horsepower is the power needed to lift 33,000 pounds 1 foot in 1 minute. It is equivalent to 746 watts. Express 525 watts as a portion of a horsepower both as a fraction and a decimal rounded to the nearest

85. College Algebra

Show all work When a person has a cavity filled, the dentist typically administers a local anesthetic. After leaving the dentist's office, one's mouth often feels numb for several hours. If a shot of anesthesia is injected into the bloodstream at the time

86. social studies

true or false. because resources are plentiful, people must make choices.

87. Physics

Force and Motion: A 12 kg armadillo runs onto a large pond of level, frictionless ice. The armadillo's initial velocity is 5m/s along the positive direction of the x-axis. Take its initial position on the ice as being the origin. It slips over the ice

88. trig

Prove the identity sin squared 0 with line/2 = csc zero with line -cot zero with a line /2csc zero with a line

89. math

Pat worked 43 hours and received \$7.25 per hour for regular pay and time-and-a-half for all hours over 40 hours. What were her weekly earnings?

90. Calculus

use the simpson's rule with n=10 to estimate arc length of y=x^(-1/3), for 1

91. Phoenix

Projectile motions problems are some of the most important problems you will encounter in this course. Through this discussion, we will solve a projectile motion problem step by step Assume a projectile is launched from ground height over a flat plane, at

92. ETSU

How much work is done when a force of 800.0 N is exerted while pushing a crate across a level floor for a distance of 1.5 m

93. algebra

One day a store sold 45 pens, the zippedy do's at \$8.50 & The Royal Blues at \$9.75. In all, \$398.75 was spent on the pens. How many Royal Blues were sold that day?

94. physics

A camera is supplied with two interchangeable lenses, whose focal lengths are 35.0 and 150.0 mm. A woman whose height is 1.80 m stands 7.00 m in front of the camera. What is the height (including sign) of her image on the film, as produced by (a) the

95. physics

The average emf induced in the secondary coil is 0.10 V when the current in the primary coil changes from 3.2 to 2.0 A in 0.10 s. What is the mutual inductance of the coils?

96. Maths

Two ships sail from port P. One sails 14km due south while the other sails 17km on a bearing of 120 degrees. Calculate to one decimal place the distance between the ships.

97. Physics

A boy with a mass of 40kg is seated a distance of 3.0m from the fulcrum of a seesaw. a. Calculate the load force exerted by the boy (Hint: What force is pulling him down?) b. Calculate the torque exerted by the boy. c. If his sister with a mass of 24 kg

98. Chemistry

10. For the titration of 20.00 mL 0.1000 M lactic acid with 0.1000 M NaOH, calculate the pH: a. before any titrant is added b. 10.00 mL prior to the equivalent point c. at the equivalent point d. 10.00 mL after the equivalence point. Plot the points

99. geometry

I need help with this question. "The measure of the supplement of an angle is 60 less than three times the measure of the complement of the angle.find the measure of the angle". Please help!!!!