# Questions Asked onMarch 25, 2012

1. ## Math-

A ball is thrown vertically upward with an initial velocity of 96 feet per second. The distance s (in feet) of the ball from the ground after t seconds is s(t)=96t-16t^2 a.) at what time will the ball strike the ground b.) for what time t is the ball more

secx/secx-tanx=sec^2x+ secx+tanx

3. ## Chemistry

The reaction: H2PO4- + HAsO42 ---> HPO4- + H2AsO4- Which one of the sets above lists both of the base species involved in the equilibrium? I'm confused and couldn't identify the conjugate acids and bases properly. Could Dr.Bob explain abt this problem ?

4. ## Chemistry

Write the acid-dissociation reaction of nitrous acid (HNO2) and its acidity constant expression.

5. ## chemistry- electrochemical cell

What makes this an oxidation-reaction? 3Ag2S+2Al(s) -> Al2S3+6 Ag(s)? Write the half-reactions showing the oxidation and reduction reactions. Identify which is the oxidation reaction and which is the reduction reason. What is oxidized in the reaction? What

6. ## Physics

A 60kg front seat passenger in a car moving initially with a speed of 18m/s (40 MPH) is brought to rest by an air bag in a time of 0.4s a. What is the impulse acting on the passenger? b.What is the average force acting on the passenger in this process?

7. ## statistics

The number of pizzas consumed per month by university students is normally distributed with a mean of 9 and a standard deviation of 5. What is the probability that in a random sample of size 10, a total of more than 80 pizzas are consumed? (Hint: What is

8. ## statistics

A person can order a new car with a choice of 9 possible colors, with or without ac, with or without heated seats, with it without anti lock breaks, with or without power windows and with or without a CD player. How many different ways can a new car be

9. ## physics

A train is moving parallel to a highway with a constant speed of 16.0 m/s. A car is traveling in the same direction as the train with a speed of 36.0 m/s. The car horn sounds at a frequency of 504 Hz, and the train whistle sounds at a frequency of 314 Hz.

10. ## spanish

Yo ______ lavo ______ manos y ______ cara. ______ cepillo ______ dientes y ______ cepillo ______ pelo. Yo ______ pongo ______ ropa.

11. ## college physics

A 0.50-kg block slides along a small track with elevated ends and a flat central part. The flat part has a length L = 1.85 m. The curved portions of the track are frictionless, but for the flat part the coefficient of kinetic friction is 0.103. The block

12. ## Chemistry

How do you prepare a 0.4 M soultion of copper sulfate in water starting with solid copper sulfate and water?

13. ## physics

A 3.00x10^-3 kg lead bullet enters a target with a speed of 2.00x10^2 m/s and comes to rest within the target. Calculate the rise in temperature of the bullet assuming that 80.0% of the heat produced is absorbed by the bullet. The Specific heat of lead is

14. ## personal finance

Alison's car is valued at $14,000, and she owes$12,000 on it. What is her current equity?

15. ## Statistics

Computer Depot is a large store that sells and repairs computers. A random sample of 110 computer repair jobs took technicians an average of 93.2 minutes per computer. Assume that o is known to be 16.9 minutes. Find a 99% confidence interval for the

16. ## Physics

A rifle with a mass of 1.2 kg fires a bullet with a mass of 6.0 (0.006kg). The bullet moves with a muzzle velocity of 600 m/s after the rifle is fired. a. What is the momentum of the bullet after the rifle is fired? b. If external forces acting on the

17. ## Biology

When you measure your heart rate for less than 20 seconds , why is it less possible for the results to be reliable? When you measure your heart rate for more than 20 seconds, why is it still less possible for the results to be reliable?

18. ## physics

A 4.5 cm tall object is placed 20 cm in front of a spherical mirror. It is desired to produce a virtual image that is upright and 3.5 cm tall. (a) What type of mirror should be used? concave mirror convex mirror (b) Where is the image located? (Your answer

19. ## chemistry

If all the energy obtained from burning 1.23 pounds of propane (fuel value is 11.09 kcal/g) is used to heat 125.0 kg of water at an initial temperature of 21.8 °C, what is the final temperature? Hint: The heat, q, released by burning propane is absorbed

20. ## Calculus

A function f is defined on the interval [0,4], and its derivative is e^sinx-2cos3x a. on what interval is f increasing? b. at what value(s) of x does f have a local maxima? c. how many points of inflection does f have? *calculator is allowed for this

21. ## Math

A function f is defined on the interval [0,4], and its derivative is e^sinx-2cos3x a. on what interval is f increasing? b. at what value(s) of x does f have a local maxima? c. how many points of inflection does f have? *calculator is allowed for this

22. ## calculus

A searchlight rotates at a rate of 4 revolutions per minute. The beam hits a wall located 9 miles away and produces a dot of light that moves horizontally along the wall. How fast (in miles per hour) is this dot moving when the angle between the beam and

23. ## chemistry

Suppose that you place exactly 100 bacteria into a flask containing nutrients for the bacteria and that you find the following data at 37 °C: TIme (s) number of bacteria 0 100 19 200 38 400 57 800 76 1600 what is the rate order? What is rate constant? how

58. ## Chemistry

use the Ksp of SnS2= 1.0X10^-70 and calculate the pH of a hydrogen sulfide solution needed to precipitate 99.99% of the tin(IV) ion assuming [Sn^4+]=0.05M and that [H2S]=0.10M.

59. ## Physics

A convex mirror forms an image of height of 2.4 cm, If the radius of curvature of thr mirror is 40 cm, find the heihgt and distance of the object from the mirror.

60. ## Physics

A playground merry-go-round made in the shape of a solid disk, has a diameter of 2.63 m and a mass of 353.9 kg. Two children, each of mass 30.5 kg, sit on opposite sides at the edge of the platform. Approximate the children as point masses. (a) What torque

61. ## Chemistry

help...If exactly 5.0 mL of HNO3 will neutralize 15 mL of 2.0 M NaOH, what is the molarity of the HNO3 solution? Have no idea what to do. thank you.

62. ## English

. In which one of the following sentences ia an abbreviation used correctly? A. I had to go to the Dr. on Monday B. Martin is a member of Parents for Responsible Teens (PRT) C. His birthday is Sept 28. D. Keep the bandage on for at least 3 hrs. Answer (b)

63. ## physics

A 1200 kg boat accelerates steadily at 0.05 m/s^2 in a straight line . Are the forces on this boat balanced or unbalanced?

64. ## child psychology

which young adult is at risk of long-term identity foreclosure or diffusion A.An aspiring chef who has no ooportunity for culinary training. B. A peace corps volunteer.

65. ## chemistry

2- A 0.310 M solution of a weak acid, HX, has a pH of 2.53 a. Find the [H+] and the percent ionization of nitrous acid in this solution. b. Write the equilibrium expression and calculate the value of Ka for the weak acid. c. Calculate the pH of the

66. ## physics

How much applied force is needed to accelerate a 2.0 kg block of wood at 4.0m/s^2 along a rough table, against a 10 N force of friction?

67. ## Physics

In the dangerous "sport" of bungee-jumping, a daring student jumps from a balloon with a specially designed elastic cord attached to his waist, as shown in Figure P5.77. The unstretched length of the cord is 25.0 m, the student weighs 675 N, and the

68. ## calculus

4. A particle starts at the point (5, 0) at t = 0 and moves along the x-axis in such a way that at time t > 0 the velocity is given by v(t)=t/(1+t^2) a. Determine the maximum velocity attained by the particle. Justify your answer. b. Determine the position

69. ## chemistry

The activation energy for the decomposition reaction, 2 HI---> H2 + Hi Is 186 kj/mol. The rate at 555 k is 3.2 x 10 -7L/mol. Sec. What is the rate at 645 k

70. ## chem

Butadiene can undergo the following reaction To form a dimer(two butadiene molecules hooked together). 2c4h8---->c8h12. The half life for the reaction at a given temperature is 5.92x10-2 sec. The reaction kinetics are second order. 1. If the initial

71. ## physics

Find the number of atoms in a gold ring of mass 6.43 g.

72. ## Algebra

Alice travels 6 times faster than Bill. Traveling in opposite directions, they are 714 miles apart after 6 hours. Find their rates of travel.

73. ## COLLEGE ALGEBRA

An investment of $63,000 was made by a business club. The investment was split into three parts and lasted one year. The first part of the investment earned 8% interest, the second 6% and the third 9%. Total interest from the investments was$4950. The

74. ## physics

A jet plane is traveling at a constant speed in a straight line in level speed. What does this tell you about the forces acting on it, what forces are acting on it .

75. ## Physics

A 15 kg child stands on the edge of a small merry-go-round of radius 2.0 m. If the merry-go- round turns at a steady rate of 11 rpm, calculate the magnitude and direction of the net force on the child.

76. ## Chemistry

I don't get this at all. A beaker with 105mL of an acetic acid buffer with a pH of 5.00 is sitting on a bench top. The total molarity of acid and conjugate base in this buffer is 0.100 M. A student adds 8.40 mL of a 0.470 M HCl solution to the beaker. How

77. ## Physics

(a) A 2.20 cm high insect is 1.24 m from a 135 mm focal-length lens. What is the image distance? mm How high is the image? cm What type is it? (Select all that apply.) The image is upright. The image is inverted. The image is behind the lens. The image is

78. ## chemistry

Calculate the pH range required to separate 99.99% of Cr3+ from Zn2+ by precipitation of Cr(OH)3(s) in a solution that is initially 0.034 M in both Cr3+ and Zn2+. Use the Ksp values from Table 16.2 of Chang and calculate the pH to the nearest 0.01 pH unit.

79. ## Statistics

A study is being planned to estimate the mean number of semester hours taken by students at a college. The population standard deviation is assumed to be o=4.7 hours. How many students should be included in the sample to be 99% confident that the sample

80. ## precal

(1/tanx-secx))+(1/(tanx+secx))=-2tanx

81. ## Chemistry

Consider the HF solution with the concentration 5%(w/v). Calculate its concentration in the molarity. Use four significant figures in the answer.

82. ## physics

a person attaches a 25kg hay bale to one end of a rope passing over a frictionless pulley connected to a beam in the hay barn. another person then pulls down on the opposite end of the rope with a force of 277-N Ignoring the mass of the rope what will be

83. ## Algebra

A ball is thrown up with an initial velocity of 32 feet per second. How many seconds will it take for the ball to return to the ground using the formula h=vt-16t^2?

84. ## Chemistry

The following system is at equilibrium,at 699K in a 5L container. H2(g)+I2(g)--->2HI(g) Kc = 54.9 Initially,the system had 2.50 moles of HI.What is the moles of H2 at equilibrium? Can Dr.Bob check if my steps are correct? My solution: Initially,the

85. ## statistics

Assume that a population is normally distributed with a mean of 100 and a standard deviation of 15. Would it be unusual for the mean of a sample of 3 to be 115 or more? Why or why not?

86. ## algebra

you can paint a room in 8 hours. your friend and you can paint a room in 5 hours together. how long does it take your friend alone?

87. ## physics

A bug that has a mass mb = 1 g walks from the center to the edge of a disk that is freely turning at 38 rpm. The disk has a mass of md = 11 g. If the radius of the disk is R = 30 cm, what is the new rate of spinning in rpm?

88. ## Physics

A wheel's uniform angular acceleration is constant. Initially its angular velocity is zero. During the first 1.0 s time interval, it rotates through an angle of 90.0°. (a) Through what angle does it rotate during the next 1.0 s time interval? (b) Through

89. ## Algebra

Mark made a business trip of 290 miles. He averaged 56 mph for the first part of the trip and 60 mph for the second part. If the trip took 5 hours, how long did he travel at each rate?

90. ## Chemistry

Calculate the concentration of the hydronium ion([H3Ol+]) for a solution with the pH = 4.5

91. ## Physics

trap door of length and width 1.65 m is held open at an angle of 65.0 degree with respect to the floor. A rope is attached to the raised edge of the door and fastened to the wall behind the door in such a position that the rope pulls perpendicularly to the

92. ## Geometry

Which of the following can be used to describe the triangle with the vertices listed below? F(-1, 1), G(-8, 1), H(-9, -10) I. acute II. obtuse III. right IV. scalene V. isosceles VI. equilateral -----Please show me how you got the answer

93. ## chemistry

Both Fe2+ and Cd2+ are precipitated by sulfide. However, they can be quantitatively separated through pH adjustment. You are given a solution containing 0.086 M Fe2+ and 0.062 M Cd2+. Calculate the [H+] range for a saturated H2S solution (ie, [H2S]=0.10 M)

94. ## chemistry

A 600ml sample of a saturated solution of MgCO3 is reduced to 125 ml by evaporation. What mass of MgCo3 is formed? Ksp=4*10^-5

95. ## Algebra

Solve the system of equations by substitution. Your answer should be given as an ordered pair like this (x, y). Round your answers to the nearest tenth. y=-2+7x 10x-7y=209

96. ## Algebra

If 3 is subtracted from the numerator of a certain fraction, the value becomes 2/3. If 10 is added to the denominator of the original fraction, the value becomes 1/2. Find the original fraction. Solve the problems by using 2 variables HOW DO I START THIS

106. ## Calculus

If a(0,-1,3)+b(1,1,1)-c(1,2,5)=(-2,3,-8), determine a,b,c Is this the correct answer: a= -4, b= -3, c= -1?

107. ## algebra

If a gardener can mow a lawn in 25 min, what portion of the lawn can the gardener mow in 1 min?

108. ## Chem 111

A solution is prepared by mixing 499 mL of 0.19 M Tris·Base and 592 mL of 0.37 M Tris·Acid. What is the pH of this solution? [Ka(Tris·Acid) = 8.5 × 10-9] Round your answer to two places past the decimal. I can do basic pH questions but I am at a loss

109. ## geometry

During the half-time show of a football game, a trumpet player and a tuba player start at the same position on the field. The trumpet player then marches 74.8 ft directly toward the goal line, and the tuba player marches directly toward the sideline. At

110. ## calculus

1. Consider the function f(x) = X^(4/3) +4x^(1/3) on the interval -8 ≤ x ≤ 8. a. Find the coordinate of all points at which the tangent to the curve is a horizontal line. b. Find the coordinate s of all points at which the tangent to the curve is a

111. ## Math

What positive value of b makes 9^2-bx+4 a perfect square trinomial? How would you solve this problem? Thanks

112. ## TEC/401

HOW the internet policies of some countries may effect a company's ability to expand globally? Current and potential uses of technology for the global success of business objectives?

113. ## LANGUAGE

a) the singing of one's name _ _ _ _ ture b) the time to leave _ _ _ _ _ ture c) silly, not acting of one's age _ _ _ _ture I swear I found all of them except these three

114. ## Chemistry

At equilibrium, it was found that [CH3COOH] = 0.8537 M, [CH3COO-] = 0.0040 M, and [H3O+] = 0.0040 M. Calculate the acidity constant of CH3COOH and the pH value of the solution. - Please show how you solve the problem.

115. ## Math

JJ's boat will go 15 mph in still water. If he can go 12 mph downstream in the same amount of time it takes to go 9 mph upstream, what is the speed of the current?

116. ## physics

An 73-kg bungee jumper is enjoying an afternoon of jumps. The jumper's first oscillation has an amplitude of 14 m and a period of 6 s. the spring constant of the bungee cord is 80.1 and max speed during oscillation is 14.7 m/s Treating the bungee cord as a

117. ## ALGEBRA

In triangle ABC, the measure of angle B is 27 degrees more than three times the measure of angle A. The measure of angle C is 48 degrees more than the measure of angle A. Find the measure of each angle.

118. ## physics

A 1-kg mass (the blue mass) is connected to a 8-kg mass (the green mass) by a massless rod 67 cm long, as shown in the figure. A hole is then drilled in the rod 40.2 cm away from the 1-kg mass, and the rod and masses are free to rotate about this pivot

119. ## English

When preparing a formal business presentation the phase that can make or break your report is the ----phase. A. writing B. outline C. revision D. organization Answer (c )

120. ## AP Calc

If y=2x-2 , what is the minimum value of the product xy? A. -16 B. -8 C. -4 D. 0 E. 2

121. ## physics

The difference between energy radiated from the sun and energy radiated from the Earth has to do with ____________________. A) Neither of these.B) Both of these.C) radiation frequencies.D) the amounts of radiant energy.

122. ## Socials

I have no idea how to answer this. Write a paragraph from Macdonald's point of view defending the decision you have made. Keep in mind your desire to look good politically and personally in your quest to get re-elected. What decision did Macdonald make??

123. ## Physics

A helicopter winches up an injured person from a boat. The person plus equipment has a mass of 104 kg. If the height of the lift is 84 m and it is carried out at a uniform rate over 70 s, what is the power expended by the helicopter's winch motor? Assume

124. ## Physics

If you are wearing contact lenses with a dioptric power of 3.4 and your eye has a diameter of 2.6 cm, what is the effective focal length of your eye-contact lens combination, in centimeters?

125. ## child psychology

Dean associates certain activites,roles, and traits as being typical for either males or females.His associations conform to cultural stereotypes and encompass many gender-linked responses.This is an example of gender: A.atypicality B.roles C.typing

126. ## Math

scientific notation 12,150,000,000 1.215 x 10(7)

127. ## math problem

please help me solve if I open a book to two facing pages, the product of the page number is 342 what will the two page numbers be

128. ## math

last week Ann ran 27 miles less than Jen. Ann ran 19 miles. How many miles did Jen run?

129. ## fun facts

what are some fun facts on multitasking? if not that what are some websites to find good fun facts

130. ## physics

The ocean level rises when global temperature rises, due to ____________________. A) Both of these.B) Neither of these.C) melting of ice caps at the poles.D) thermal expansion of water

131. ## physics

The temperature at the bottom of Lake Tahoe in the Sierra Nevada Mountains of California is 4°C year round. In which country is water at the bottom of lakes normally higher than this? A) Russia.B) Great Britain.C) New Zealand.D) Tibet.E) Singapore.

132. ## math

Bob finds that the cost of driving his truck is 92 cents per mile. Give a symbolic and graphical representation for a function f(x) that computes the cost in dollars of driving x miles. Assume 0

133. ## Living Environment

Tell whether each of the following substances that is filtered from the blood in the glomerulus is reabsorbed, excreted as part of the urine, or both

220. ## ps 189

if a aluminum can has a radius of 10cm and a height of 20 cm. how many square cm of aluminum does it take to make such a can.

221. ## Criminal Justice

If judicial review were eliminated, what alternative means could be used to interpret the meaning of the Constitution?

222. ## precal

1-cosx/1+cosx=(cotx-cscx)^2

223. ## social studies

How were religion and the Roman government related?

224. ## English

Writeacher, I'm still working on my paragraph on the presentation of the Irish school. I really hope you'll be there in three hours' time to check if everything is OK. By the way, can you suggest a website, on which (?) phrasal verbs are grouped according

225. ## Math 8

6 1/2 joules. particles looses 0.08 joule of energy every 15 seconds what will energy after 4 minutes. Would this be 6 1/2 - 1.28 divide by 4

226. ## science

a 2000 kg sedan is traveling west at 25m/s. How would the sedan's momentum change if it slowed down to 10 m/s?

227. ## Pre Cal

cos^2+tan^2=1

228. ## Pre-Calculus

Sketch the graph f(x)=-2x^2(x-5)^3(x+2)^4. What would be my coordinates. I solved it and my graph looks nothing like the one on wolframalpha. Can someone show me how you would solve this?

229. ## Math

What are the values of x for 2x-1=0

230. ## math

find x when f(x)=1 f(x)= x^2+x-12/x^2-4

231. ## Math

Finding the base or number : 9 is 15% of what number? example please.

232. ## Geometry

two perpendicular lines with the equations y=1/3x+9 and y=mx-3 contain the consecutive sides of a rectangle. What is the value of mx in the 2nd linear question.

233. ## healthcare

how can you review and develop your work performance at aged care

234. ## Criminal Justice

Should judicial review be eliminated? Provide a detailed explanation for your answer.

235. ## Calculus AP need help!

antiderivative. find f. f'(x)= 3x^(-2), f(1)=f(-1)=0

237. ## Derivatives

differentiate and simplify y= (e^x - 1) / x^2

238. ## science

2 mole jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj

239. ## Science

What does a thermohygrometer do?