# Questions Asked onMarch 12, 2011

1. ## physics

What are the first three harmonics of a note produced on a 31.0 cm long violin string if waves on this string have a speed of 277.0 m/s? Hz Hz Hz

2. ## health safety nutrition

A child who drinks a lot of milk but rejects most solid foods may develop the symptoms of ____ because the child is deficient in the mineral ____. A) anemia, iron B) indigestion, phosphorus C) kidney stones, iron D) rickets, calcium

3. ## Calculus

a) Find a Cartesian equation relating and corresponding to the parametric equations: x=2sin(3t), y=9cos(3t). Write your answer in the form P(x,y)=0, where P(x,y) is a polynomial in x and y, such that the coefficient of y^2 is 4. b)Find the equation of the

4. ## Calculus

a 16 foot ladder is leaning against a building. the bottom of the ladder os sliding along the pavement at 3 ft/s How fast is the top of the ladder moving down when the foot of the ladder is 2 ft from the wall

5. ## calculus

A plane flies horizontally with a speed Of 600km/h at an altitude of 10km and pasess directly over th town of quinton .find the rate at which the distance from the plane to quinton is increasing when its 20km away from quinton ?

6. ## Chemistry

The blank solution used to calibrate the spectrophotometer is 10.0mL of 0.2M Fe(NO3)3 diluted to 25.0mL with 0.1M HNO3. Why is this solution preferred to simply using de-ionized water for the calibration?

7. ## health safety and nutrition

The mineral ____ and vitamins ____ and ____ regulate bone and tooth formation. A) calcium, K, E B) iron, A, D C) magnesium, C, B12 D) calcium, A, D

8. ## physical

three displacement vectors of a croquet ball are shown in figure p3.49, where |a| = 20.0 units, |b| = 40.0 units, and |c| = 30.0 units. find (a) the resultant in unit–vector notation and (b) the magnitude and direction of the resultant displacement

9. ## Calculus PLEASE check my work ,

1.) which of the following represents dy/dx when y=e^-2x Sec(3x)? A.3e^-2x sec(3x) tan (3x)-2e^-2x Sec(3x)

10. ## Chemistry

At 1473K the equilibrium constant for the reaction H2(g) + Cl2(g) 2HCl(g) Kc = 2.5*10^4. What would be the equilibrium concentration of HCL if the initial concentrations of H2 and Cl2 were 0.1840M and 0.1918M. I got 29.7 but was told it was wrong

11. ## physics

A stereo speaker represented by P in Figure 13-22 emits sound waves with a power output of 130.0 W. What is the intensity of the sound waves at point x when r = 7.8 m? W/m2

12. ## Math 157

assume that a reseacher randomly selected 14 new born babies and counts the number of girls selected x. the probability corresponding to the 14 possible values of x. find the probability of selecting exactly 8 girls.

13. ## health safety

All of the following foods are common allergens EXCEPT: A) eggs B) orange juice C) rice D) whole wheat bread

14. ## Chemistry

For preparing a set of standard solutions of FeNCS2+, the equilibrium molar concentration of FeNCS2+ is assumed to equal the initial molar concentration of the (SCN-) in the reaction mixture. why is this assumption valid?

15. ## Chemistry

55g of CF2Cl2, how many grams of Cl do I have? How do I solve this kind of problem?

16. ## Physics

a dense plastic toy mass of 1.2kg is floating just beneath the surface of a pond. What is the bouyant force?

17. ## Science

Calculate the amount of heat required to completely sublime 63.0 g of solid dry ice CO2 at its sublimation temperature. The heat of sublimation for carbon dioxide is 32.3 C.

18. ## Chemistry

You are asked to go into the lab and prepare an acetic acid-sodium acetate buffer solution with a pH of 5.43 ± 0.02. What molar ratio of CH3COOH to CH3COONa should be used?

19. ## Health, safety, and nutrition

An important vitamin-mineral combination that promotes bone growth and maintenance is

20. ## AP Biology

A biologist measured the amount of DNA in several single diploid cells taken from a culture. He knew that these cells could divide mitotically, but not meiotically. His data is shown below: Cell Number and DNA content in micrograms: Cell 1 (11.1

21. ## Chemistry

the pka of acetone is CH3COCH3 is 19.3 which of these bases is strong enough to deprotonate acetone? a)KOH (pka of H20 = 15.7) b)Na+ -C(triplebond)CH (pka of C2H2 = 25) c)NaHCO3 (pka of H2CO3 = 6.4) d)NaOCH3 pka of CH3OH = 15.6) i know the answer is b but

22. ## Science

Calculate the amount of heat required to completely sublime 63.0 g of solid dry ice CO2 at its sublimation temperature. The heat of sublimation for carbon dioxide is 32.3 C.

23. ## chemistry

Heterogenous equilibrium of ammonium bisulfide. Ammonium bisulfide NH4HS forms ammonia NH3 and hydrogen sulfide H2S through the reaction NH4HS(s) arrows + H2S(g). This reaction has a kp value of 0.120 at 25 C. A 5.0-L flask is charged with .400g of pure

24. ## Math

In a mobile phone network, how many times as strong would a signal be expected to be at 200 m from a base station, compared with at 600 m? My answer is 81, is it right?

25. ## math

A particle is traveling along a one-dimensional path (such as a number line). The position of the particle is governed by the time function x(t) ƒ­ 3t 4 ƒ{16t3 ƒy18t 2 ƒy 2 , where t is in minutes and 0 „T t „T 5 . Answer the following questions.

26. ## math

Suppose the 435 members of the house of representatives are placed on committees consisting of more than 2 members but fewer than 30 member of members and each member is to be on one committees. Each committee is to have an equal number of members and each

27. ## chem

What is the pH of a 1.00 molar solution of NaNO3(aq)?The Ka for nitric is 0.0007.show all calculations

28. ## CHM 101

The food dyes contain propylene glycol in addition to the dyes and water. The candy shells contain sucrose, corn syrup, corn starch and gum acacia. Do you think this affects the movement of the dyes on the chromatography paper?

29. ## Calculus

a pond that lies in a crater is being drained at the rate of 1000m3/min.If the crater has the shape of an inverted cone of radius 200(at he original water level) and original depth is 50 m (at the center) find that rate at which the water level begins to

30. ## english

In comparing an oak tree with a maple tree, you can correctly say that A. oak is often used to make ships, while maple is often used for furniture. B. both maple and oak trees lose their leaves in the fall. C. acorns are good to eat, while maple seeds

31. ## CHEM

WHAT IS THE pH of 1.00 molar solution of NaNO3(aq)? The Ka for nitric acid is 0.0007.show all calculations

32. ## Chemistry

A buffer is prepared by adding 0.97 L of 1.1 M HCl to 805 mL of 1.7 M NaHCOO. What is the pH of this buffer? [Ka(HCOOH) = 1.7 × 10-4]

33. ## History

Can someone please explain what this statment means when it worded like this? (I tried to figure out what it means, put I keep getting confuse). That the 1912 election registered, and inspired, fundamental changes in American politics suggests the

34. ## Calculus

1.evaluate (integral sign)x cos 3x dx A.1/6 x^2 sin 3x + C B.1/3 x sin 3x -1/2 sin 3x +C C.1/3 x sin 3x +1/9 cos 3x +C

35. ## chemistry

I tried using the answer you provided but the online system I am using is not taking this as a correct answer. This is the answer you provided: AgCl(s) + H2O(l) ==> Ag^+(aq) + Cl^-(aq). PLEASE HELP!! Thanks My original question: Write the equation for the

36. ## Computer Science

The digits 0, 1, and 8 look much the same if rotated 180 degrees on the page (turned upside down). Also, the digit 6 looks much like a 9, and vice versa, when rotated 180 degrees on the page. A multi-digit number may also look like itself when rotated on

37. ## Chemistry

A solution is made by dissolving 3.550g of Na2SO4 in water using a 100.0 mL volumetric flask. What is the molarity of the solution?

38. ## Math 157

when a coin is tossed 4 times, 16 equally likely outcomes are possible, what are they

39. ## physics

The mass of a certain neutron star is 2.0 x 1030 kg and its radius is 6,000 m (6 km). What is the acceleration of gravity at the surface of this condensed, burned out star?

40. ## Diff eqn- IVP

A simple pendulum of length is oscillating through a small angle θ in a medium for which the resistance is proportional to the velocity. Obtain the differential equation of its motion and discuss the motion.

41. ## math

1) If the number 1,1/3,1/9, are terms of Geometric progression. Find its common ratio 2) If the second term of Geometric progression is equal to 3, and the 5th term is equal to 81/8. Find the 7th term. 3)If x,y,3 is a Geometric progression. Find the value

42. ## Fin 324

Income and retained earnings relationships: Assume that retained earnings increased by \$375,000 from December 31, 2008 to December 31, 2009, for jarvie Distribution Corporation. During the year, a cash dividend of \$135,000 was paid. 1. Compute the net

43. ## chemistry

What is the molar concentration of calcium hydroxide that has 0.185g solute in 100ml solution?

44. ## Marketing

1. Recently American Express, Visa and MasterCard have been pushing hard into the small-ticket end of the credit card market. The purchase of items such as fast food meals, and movie popcorn and candy have been targeted as growth areas for credit card

45. ## physics

An electric kettle operates at 230V and draws a current of 13A. What would the equivalent current be at the following voltages used in the UK National Grid? Show all your working. a) 33kV (33000V) (4 marks) b) 400kV (4 marks)

46. ## Computer Science

The digits 0, 1, and 8 look much the same if rotated 180 degrees on the page (turned upside down). Also, the digit 6 looks much like a 9, and vice versa, when rotated 180 degrees on the page. A multi-digit number may also look like itself when rotated on

47. ## Calculus

a pond that lies in a crater is being drained att he rate of 1000m3/min.If the crater has the shape of an inverted cone of radius 200(at he original water level) and original depth is 50 m (at the center) find that rate at which the water level begins to

48. ## Calculus

A plane flies horizontally with a speed Of 600km/h at an altitude of 10km and pasess directly over th town of quinton .find the rate at which the distance from the plane to quinton is increasing when its 20km away from quinton ?

49. ## Electrical

Given the following system equations: -Put them into Standard Form, and -Simplify using Cramer’s rule IS + G1 (VA + VB) – G2VB = 0 G2VB + G1 (VA – VB) = 0

\$3\4LB

51. ## physics

Green light has a wavelength of 4.96 10-7 m and travels through the air at a speed of 3.00 108 m/s. Calculate the period of green light waves with this wavelength. s What is the frequency? Hz

52. ## Computer Science

In 256PSK, how many bits will each symbol be able to represent? My answer is 8. is it correct?

53. ## comm 156

Read pp. 290–291 in Ch. 18. Those pages provide an overview of writing that persuades. Ch. 4 provides ideas for choosing a topic. Based on those ideas and knowing that your final paper will be a persuasive essay, what topic from Appendix B will you

54. ## astronomy

Calculate the average speed of a water molecule (with a mass of 3.0e-26 kg) on the hot side of Mercury (710 Kelvin).

55. ## Statistics

A random sample is obtained from a normal population with a mean that equals 80 and a standard deviation that equals 8

56. ## Chemistry Help!

4 NH3 + 5 O2 ¨ 4 NO + 6 H2O If the rate of disappearance of O2 is 0.772, what is the rate of appearance of NO?

I have the first part done with either Marriott Intl or southwest airlines it is the second and third parts i am stuck on here is the entire assignment Assignment Type: Individual Project Deliverable Length: 4-5 body pages, 1 PERT chart, 1 Gantt chart

58. ## health safety

Nutrition activities that would also promote children’s motor skill development include: A) looking at a display of ethnic foods B) measuring ingredients for a recipe C) peeling and slicing bananas for a fruit salad D) reading a rhyming story about foods

59. ## chemistry

Why sodium oxide is a solid at room temperature whereas sulfur trioxide is a low boiling point liquid?

60. ## statistics

Use the central limit theorem to find the approximate probability that the mean number of flaws exceeds 1.6 per square yard. (Round your answer to four decimal places.)

61. ## Calculus (fixed the typo )

A line rotates in a horizontal plane according to the equation theta=2t^3 -6t,where theta is the angular position of the rotating line, in radians ,and t is the time,in seconds. Determine the angular acceleration when t=2sec. A.) 6 radians per sec^2 B.) 12

62. ## Chemistry

The boiling ponit of phophine is -85 oC, whilst of ammonia in the same group is -33.5 oC, how can we account for this difference in BP?

63. ## science

CAN SOMEONE ANSWER THIS QUESTION The question still remains, where did life come from?

64. ## chemistry

What volume of a 0.34M MgCL2 solution is required to make 250ml of a 0.10M solution by dilution?

65. ## chemistry

i posted this already but i got the answer for someone elses question. the pka of acetone is CH3COCH3 is 19.3 which of these bases is strong enough to deprotonate acetone? a)KOH (pka of H20 = 15.7) b)Na+ -C(triplebond)CH (pka of C2H2 = 25) c)NaHCO3 (pka of

66. ## Computer Science

The digits 0, 1, and 8 look much the same if rotated 180 degrees on the page (turned upside down). Also, the digit 6 looks much like a 9, and vice versa, when rotated 180 degrees on the page. A multi-digit number may also look like itself when rotated on

67. ## chemistry

If a solid is produced, after Silver Nitrate is added, what eventually might happen?

68. ## physics

An electric kettle operates at 230V and draws a current of 13A. What would the equivalent current be at the following voltages used in the UK National Grid? Show all your working. a) 33kV (33000V) (4 marks) b) 400kV (4 marks)

69. ## physics

A circuit breaker uses an electromagnet. Explain why the current is cut off by a circuit breaker if it is larger than a certain value.

70. ## c programming

every week from monday to friday you go to class. when it is raining, you take an umbrella. but on the weekend,what you do depends on the weather. if it is raining, you stay indoors. otherwise, you have fun outdoors. write a c program to present your

71. ## chemistry

You are given a bottle of household vinegar of volume 500 cubic centimeters. Design an experiment to determine its concentration. Add illustrations

72. ## physics

give one advantage of the type of circuit in a circuit breaker compared with a cartridge fuse

73. ## maths

perimeter of a equilateral triangle is given as 42 cm. Find the perimeter of a shaded part of triangle if the 3 sectors of a circle marked are identical

74. ## math

If there are 6 blue marbles and 2 red marbles in a bag, what is the probability of picking a blue marble then another blue marble if you do not replace the first marble P(B,B)? 3/4 x 5/7 or is it 3/4 x 6/7?

75. ## Algebra 2

You have 10 coins..3 quarters,5 dimes, and 2 nickels. a. A coin is selected and then replaced. A second coin is selected and then replaced. A third coin is selected and then replaced. Find the probability that all 3 coins were dimes.

76. ## calculus

Which of the following is a step in evaluating ç(integer sign) cos^2 5x dx A.ç(integer sign) 1 + cos 10x / 2 dx B.ç(integer sign) 1 - cos 10x / 2 dx C.ç(integer sign) 1 + cos 10x / 20 dx D.ç(integer sign) 1 - cos 10x / 20 dx A

77. ## Finance

what would be your monthly car payment on a \$15000 4 year loan @ 10%. Payments are made at the end of each month

78. ## statistics

In a show the rate of an adult pass is Rs. 20 more then the children pass. when a company sold 50 adult passes and 200 children passes,the amount collected is rs.2250. find the price of an adult pass?

79. ## chemistry

what mass of X can be dissolved in 35.0 grams of water at 20 degrees centigrate?

80. ## algebra

Perimeter of a rectangle. The width of a rectangle is three fourths of the length. The perimeter of the rectangle becomes 50 cm when the length and the width are each increased by 2 cm. Find the length and the width.

81. ## algebra

Calculate the average speed of a water molecule (with a mass of 3.0e-26 kg) on the hot side of Mercury (710 Kelvin).

82. ## algebra

3. You are going to plant trees in your hilly backyard. Tree A is located at coordinates (1,4) and Tree B is located at (5,12). What is the slope of the hill between the two trees?

83. ## statistics

In a show the rate of an adult pass is Rs. 20 more then the children pass. when a company sold 50 adult passes and 200 children passes,the amount collected is rs.2250. find the price of an adult pass?

84. ## calculus

Write an equation of the line tangent to y=(9-x^2)^2/3 at x=1

85. ## spanish

help me translate please!! i tried it myself but it was a mess! :( My name is Isabella and I am 14 years old. I live with my parents and two brothers in the outskirts of Newport. My school is a few miles away from where I live, I go to school by coach but

86. ## engineering

Design a packed tower for the absorption SO2 from air. The SO2 feed contain 0.0016 mol frac A into pure water in column that is 1.5 m2 cross sectional area and 3.5 m in height. The flow rates of entering gas and liquid are 111.5 kmol/h and 3860 kmol/h,

87. ## Electrical

(2) 1500 Ù resistors are connected in series. They are then connected in parallel to a single (1) 5 kÙ resistor. a) Draw the circuit before and after reduction: b) What is the equivalent resistance of the circuit?

88. ## physics

A circuit breaker uses an electromagnet. Explain why the current is cut off by a circuit breaker if it is larger than a certain value.

89. ## maths

Hi... i am sturgling with this Question it is ... calculatethe volume of the rectangelar box lenght 18 widht 6 height 9

90. ## statistics

What type of data must you collect to conduct a t-test, why?

91. ## calculus

Question: what is the derivative of f(x)=x^2*e^x Would the answer simply be 2x+e^x?

92. ## Calculus (check)

Evaluate ç dx/sqrt9-8x-x^2 A.sin^-1 (x + 4/5) + C B.sin^-1 (x - 4/5) + C C.Ln Sqrt9-8x-x^2 + C D.Ln (-8 - 2x) + C B or C ?

93. ## science

There are 150 grams of water in a beaker. If the water freezes,what is the massof the ice?

94. ## geography

why does the best place for a reservoir have to be a river valley in an upland area with steep sided slopes to act as natural walls. Why cant is be flat?

95. ## physics

Using the circuit for an electric bell, a) Explain why the bell won't work if the elctromagnet is replaced with a permanent magnet. (2 marks) b)Explain why the core of the electromagnet used in an electric bell must not be made from steel. (3 marks)

96. ## english

can you evaluate my essay ? tell me waht do you think about it, and what should i do to improve it. Satisfaction The grass is always greener on the other side of the fence. This saying made me think about life, people, and their attitude toward it. This

97. ## Chem

How to write compound in given atoms

98. ## Statistics- Help

I need help with this problem for school. For the first one i got .3758 and second 1.6, but i don't think they are right. My calculations are off It is known that about 20% of car insurance policies include emergency road service. Suppose we randomly

99. ## Chemistry

A solution whose molarity was found to be 0.5molar contain A, B, &S what is the mole friction of S given that is no S number moles is 0.07. Also determine his moles percentage?

100. ## calculus

what are the steps to solve for x 2x^2-1/x^2=0

101. ## calculus

What is the derivative of f(x)=e^-3x

102. ## calculus

Consider the function f(x)=In(x^2+1). Calculate the slope of the tangent line at the point (2,ln(5)). Round your answer to two decimal places.

103. ## unit circle

how does the direction ( clockwise or counterclockwise effect the values of the unit circle? what does it mean?

104. ## Social

Key difference/s between the 1929 Crash and previous stockmarket crashes was/were A) The impact of the investor's pools B) That many middle income people were stockholders C) All of the choices D) The government's intervention I think it's all of the

105. ## calculas

If sin theta equals two third and zero degrees less than theta less than 90 degrees find cosine theta

106. ## Diff eqn- IVP

A particle moves on the x-axis with an acceleration, a=(6t-4)ms⁻1. Find the position and velocity of the particle at t=3 , if the particle is at origin and has a velocity of when t=0

107. ## physics

Using the circuit for an electric bell, a) Explain why the bell won't work if the elctromagnet is replaced with a permanent magnet. (2 marks) b)Explain why the core of the electromagnet used in an electric bell must not be made from steel. (3 marks)

108. ## chemistry

How many grams of NaOH are there in 2.5L of a 0.343M solution?

109. ## chemistry

Determine the weight of Calcium Carbonate decomposed to produce 4 liters of Carbon Dioxide.

110. ## geography

what does it mean by the follwing: The graph shows that in 2005 and 2006 there were long periods where the rainfall was below average. This would lead to problems such as reservoir levels dropping and water restrictions, for example, hosepipe bans. By

111. ## geography

why does scotland, wales and WW england have the most rainfall compared to the most populated like SE England.

112. ## Electrical

A device is rated to operate at a voltage of 24V. It has a protection circuit consisting of (4) 25 A fuses. a) Discuss whether these fuses are connected in series or parallel? b) What is the maximum power of the device? c) If this device was redesigned to

113. ## Marketing

An economics student would like to buy a mini-scooter, but she cannot afford one. Which of the following reasons explain why marketing fails to occur here? (Points : 1) two or more parties with unsatisfied needs a desire on the part of each to satisfy the

114. ## Calculus

if x=e^t and y=(t-3)^2 , find an equation y=mx+b of the tangent to the curve at (1,9).

115. ## math

perform row operations x+2y=0 y-z=2 x+y+z=-2

116. ## COM/155

Can you take a look and tell me what you thing? Thanks Review the passage below, which contains 20 errors. Identify these errors by marking each of the errors in bold, and make your correction in parentheses after the error. Example: My cars interior is

117. ## physics

give one advantage of the type of circuit in a circuit breaker compared with a cartridge fuse?

118. ## GEOGRAPHY

how does an underground reservoir work?how can this be true because I thought a reservoir was a lake of water- how can this be underground?

119. ## trig

prove that (sin^4x-cos^4x)/(sinx-cosx) = sinx+cosx

120. ## Chemistry

A solution whose molarity was found to be 0.5molar contain A, B, &S what is the mole friction of S given that is no S number moles is 0.07. Also determine his moles percentage?

121. ## Math

How would you writ the set of all recipricols of the natural numbers? I think it's (1/1 (I don't know if 1/1 is considered part of it) 1/2,1/3, 1/4, 1/5...) Is this correct? thanks

122. ## English

why diversity is or is not an important element of our Canadian culture in your opinion?

123. ## math

matt used centimeter cubes to make a solid that had a volume of 5 cubic centimeters and a surface area of 22 square centimeters. what might his solid looked like?

How can knowledge of the direct and indirect approaches help writers write “efficiently and effectively

125. ## geography

what is resource exploitation?

126. ## College

Briefly describe two life experiences and illustrate how each will be useful as you pursue academic goals.

127. ## Chemistry

what is the mass percentage of Na in Nacl

128. ## geography

how can aquifers lead to cities sinking? simple explanation please so easy to understand