# Questions Asked onFebruary 7, 2011

1. ## Physics

what is the required resistance of an immersion heater that will increase the temperature of 1.50 kg of water from 10 degrees C to 50 degrees C in 10 minutes while operating 120 V?

2. ## algebra

ax/b + cx/d =e solve for variable x

3. ## physics!

A 1.60-kg bottle of vintage wine is lying horizontally in a rack. The two surfaces on which the bottle rests are 90.0° apart, and the right surface makes an angle of 45.0° with respect to the horizontal. Each surface exerts a force on the bottle that is

4. ## Calculus

Let f be a twice-differentiable function such that f(2)=5 and f(5)=2. Let g be the function given by g(x)= f(f(x)). (a) Explain why there must be a value c for 2 < c < 5 such that f'(c) = -1. (b) Show that g' (2) = g' (5). Use this result to explain why

11. ## statistics

Suppose that the heights of adult men in the United States are normally distributed with a mean of inches and a standard deviation of inches. What proportion of the adult men in United States are more than feet tall? (Hint: feet inches.) Round your answer

12. ## Real number system

2,874 to base five

13. ## Physics

In a certain stereo system, each speaker has a resistance of 4 Ω. The system is rated at 60 W in each channel. Each speaker circuit includes a fuse rated at a maximum current of 4 A. Is this system adequately protected against overload?

14. ## Science

Why are there so many villi and air sacs?

15. ## algebra 2

suppose a house that costs $270,000 appreciates by 5% each year. in about how many years will the house be worth$350,000? use the equation 350 = (270) (1.05)^x and round the value of x to the nearest year.

16. ## spanish

¿Cuál es la forma correcta del imperativo para tú? ¡_____ aquí! (venir) ¿Cuál es la forma correcta del verbo para el imperativo tú? ¡______ a las siete! (salir) ¿Cuál es el imperativo para la forma tú? ¡No ______ ahora! (salir)

17. ## Algebra

A Camp leader figures she needs one tent for every three campers plus one for herself...write an expression that reprents this.

18. ## Physics

An electron moves at a speed of 6.0 x 10^-6 perpendicular to a constant magnetic field. The path is a circle of radius 1.3 x 10^-3m. What is the magnitude of the field. Find the magnitude of the electron acceleration.

19. ## Physics (76)

the weight of the block on the table is 422 N and that of the hanging block is 185 N. Ignoring all frictional effects and assuming the pulley to be massless, find (a) the acceleration of the two blocks and (b) the tension in the cord.

20. ## Physics

Astronauts use a centrifuge to simulate the acceleration of a rocket launch. The centrifuge takes 40.0s to speed up from rest to its top speed of 1 rotation every 1.40s . The astronaut is strapped into a seat 4.50m from the axis. What is the astronaut's

21. ## physics

what is the velocity of a 53.7 kg jogger with a kinetic energy of 1054 J?

22. ## physics

A spelunker (cave explorer) drops a stone from rest into a hole. The speed of sound is 343 m/s in air, and the sound of the stone striking the bottom is heard 3.24 s after the stone is dropped. How deep is the hole?

23. ## kassie

What is the major product of the reaction between methanol and (2R,3S)-2-bromo-3-methylpentane at room temperature?

24. ## physics

The tops of the towers of the golden gate bridge in san Francisco, are 227m above the water. suppose a worker drops a 655g wrench from the top of a tower. if the average force of air resistance is 2.20 percent of the force of free fall what will the

25. ## algebra

A simple economy consists of two industries: agriculture and manifacturing. The production of 1 unit of agricultural products requires the consumption of 0.2 units of agricultural products and 0.15 units of manufactured goods. The production of 1 unit of

26. ## AP European History

What is the relationship between the study of geography and the study of history? What are the advantages and disadvantages of Europe’s geography? Explain the impact of Europe’s geography on European History. This is what I have so far: How are

27. ## Algebra

A wire is run between two tips of two poles. One pole is 23 ft. taller than the other pole. The poles are 37 ft. apart. How long does the wire need to be to reach between the two poles?

28. ## theory of dressmaking

what is disposal of fullness

29. ## physics homework! #92

A small sphere is hung by a string from the ceiling of a van. When the van is stationary, the sphere hangs vertically. However, when the van accelerates, the sphere swings backward so that the string makes an angle of è with respect to the vertical. Find

30. ## Chemistry

A fish tank holds 40 gallons of water (density 1.00g/mL) when full. What is the mass of the water in kilograms (kg)?

31. ## chemistry

what mass of K2SO4 would you measure out to prepare 550 mL of a 0.76 M solution?

Mrs. Reid brought 32 orange and apple slices to her daughter's soccer practice. There were three times as many orange slices as there were apple slices. How many of each kind did she bring?

33. ## Physics

the heating element of a coffee maker operates at 120 V and carries a current of 2 A. Assuming that the water absorbs all of the energy converted by the resistor, calculate how long it takes to heat .500 kg of water from room temperature 23 degrees C to

34. ## Science

How was their small size helpful to the mammals of the Mesozoic?

35. ## chemisty

115 grams of KCl is dissolved in 750 ml of water. what are the molality, molarity, mole percent, % mass, ppm by mass. what would the freezing point and boiling point of that solution assuming Kf of water is 1.86 degree celsius/m and Kb is .0512 degree

36. ## physics

A Boeing 747 "Jumbo Jet" has a length of 59.7 m. The runway on which the plane lands intersects another runway. The width of the intersection is 21.3 m. The plane decelerates through the intersection at a rate of 5.33 m/s2 and clears it with a final speed

37. ## physics

When you try to walk too fast on a slippery floor, you slip because walking fast requires you to exert a greater frictional force against the floor than the surface allows. What is the maximum frictional force you can exert against the floor with one foot

38. ## Physics

A block of mass 2.10 kg is pushed 2.33 m along a frictionless horizontal table by a constant 19.4 N force directed 27.5o below the horizontal. Determine the magnitude of the normal force exerted by the table.

39. ## math

Find the periodic payment R required to amortize a loan of P dollars over t yr with interest charged at the rate of r%/year compounded m times a year. P = 16,000, r = 8, t = 6, m = 6

40. ## physics

A dynamite blast at a quarry launches a rock straight upward, and 2.0 s later it is rising at a rate of 15 m/s. Assuming air resistance has no effect on the rock, calculate its speed (a) at launch and (b)4.2 s after launch.

41. ## Physics

Skater N, 58.9 kg, is moving north at a speed of 7.8 m/s when she collides with Skater E, 72.6 kg, moving east at 3.5 m/s. The two skaters are stuck together. In what direction and with what speed do they move after the collision?

42. ## physics

2.5 kg rifle fires a 20 g bullet at 400 m/s. Find magnitude of the recoil velocity of the rifle.

43. ## physics! (69)

A damp washcloth is hung over the edge of a table to dry. Thus, part (mass = mon) of the washcloth rests on the table and part (mass = moff) does not. The coefficient of static friction between the table and the washcloth is 0.395. Determine the maximum

44. ## AED205

I need help with week 9 capstone discussion question. What are the five most valuable classroom management concepts that build a positive learning environment? Why did you select those concepts out of all of the concepts learned? How will you apply those

45. ## English

More than a thousand people are killed in a road accident during the december holiday.How can this carnage on our road be stopped?

46. ## physics

A cheetah is hunting. Its prey runs for 4.3 s at a constant velocity of +8.4 m/s. Starting from rest, what constant acceleration must the cheetah maintain in order to run the same distance as its prey runs in the same time?

47. ## English 3

In the Adventures of Huckleberry Finn, Huck mentions that he wishes the Widow Douglas could know about his efforts to save the men on the wreck of the Walter Scott. Pretend that you are Huck and write a letter to the Widow, explaining the situation and

48. ## Chemistry

Gold can be recovered from sea water by reacting the water with zinc, which is refined from zinc oxide. The zinc displaces the gold in the water. What mass of gold can be recovered if 2.00g of ZnO and an excess of sea water are available? 2ZnO + C -> 2Zn +

49. ## physics

a uranium-238 nucleus may stay in one piece for billions of years, but later it decays into an a particle of mass 6.64 x 10^-27 and a thorium-234 nucleus of mass 3.88 x 10^-25. The decay process itself is extremely fast (about 10^-20 s). Suppose the

50. ## Discrete Math

Consider the following relations on R, the set of real numbers a. R1: x, y ∈ R if and only if x = y. b. R2: x, y ∈ R if and only if x ≥ y. c. R3 : x, y ∈ R if and only if xy < 0. Determine whether or not each relation is flexible, symmetric,

51. ## Physics

Read each statement below. For each situation, calculate vi, vf, pi, pf, the impulse vector F􏰁t, and the amount of force needed for the change to occur. All situations refer to a truck with a mass of 2840 kg. 1. The truck has a velocity of 8.30 m/s and

52. ## Physics

A block of mass 2.10 kg is pushed 2.33 m along a frictionless horizontal table by a constant 19.4 N force directed 27.5o below the horizontal. Determine the magnitude of the normal force exerted by the table.

53. ## physics

A Boeing 747 "Jumbo Jet" has a length of 59.7 m. The runway on which the plane lands intersects another runway. The width of the intersection is 21.3 m. The plane decelerates through the intersection at a rate of 5.33 m/s2 and clears it with a final speed

If a woman lifts a 19.3 kg bucket from a well and does 6.10 kJ of work, how deep is the well? Assume that the speed of the bucket remains constant as it is lifted

55. ## geometry

Figure ABCD is a square. Angle B measures (15x-13)Find the value of x.

56. ## physics

a 2.5 kg rifle fires a 20 g bullet at 400 m/s. What is the magnitude of the recoil velocity of the rifle? I still don't understand. Could you please help with a formula? Thank you. physics - drwls, Monday, February 7, 2011 at 6:38pm Try using conservation

57. ## English 3

In The Adventures of Huckleberry Finn, Huck struggles to decide what he should do when his heart and his conscience pull him in different directions. He eventually decides to go with his heart. Write a short essay explaining why you agree or disagree that

58. ## Physics

A block of mass 2.10 kg is pushed 2.33 m along a frictionless horizontal table by a constant 19.4 N force directed 27.5o below the horizontal. Determine the magnitude of the normal force exerted by the table.

59. ## physics

Approximate the gravitational force of attraction between a 49.0 kg girl and a 52.0 kg boy if they are sitting 2.5 m apart

60. ## physics

a worker drives a .551 kg spike into a rail tie with a 2.55 kg sledgehammer. The hammer hits the spke with a speed of 62.1 m/s. if one fourth of the hammers kinetic energy is converted to the internal energy of the hammer and soike, how much does the total

61. ## Physics

Skater N, 58.9 kg, is moving north at a speed of 7.8 m/s when she collides with Skater E, 72.6 kg, moving east at 3.5 m/s. The two skaters are stuck together. In what direction and with what speed do they move after the collision?

62. ## math

Suppose that 28 crayons, of which four are red, are divided random among Jack, Marty, Sharon, and Martha (seven each). If Sharon has exactly one red crayon, what is the probability that Marty has the remaining 3?

63. ## Physics GO! (82)

To hoist himself into a tree, a 72.0-kg man ties one end of a nylon rope around his waist and throws the other end over a branch of the tree. He then pulls downward on the free end of the rope with a force of 365 N. Neglect any friction between the rope

72. ## Math7

Yuki made cookies on Monday. Some friends came over and ate half the cookies on Tuesday. On wednesday,Yuki ate three cookies, and on Thursday, she took two cookies to school. By Friday, Yuki had seven cookies left. How many did she bake on Monday? Please i

73. ## Physical Science

Suppose you dissolve 40g of potassium nitrate in 100 cm3 of water at 100 C. If half the solution os poured out, how many grams of potassium nitrate will the remaining solution contain?

74. ## math

A fireman stood in the middle of a step ladder. He climbed down 4 steps and continued his work. He went down 8 more then back up 9 to the top. How many steps were on the ladder?

75. ## math

If it takes a person to walk 30 minutes in 3 miles..how many minutes would it take a person who walks 3.5 miles be?

76. ## chem

Fish-liver oil is a good source of Vitamin A. When 0.1232 g of fish liver oil is dissolved in 500. mL of solvent, an absorbance of 0.724 is recorded. When 0.00167 g of Vitamin A is dissolved in 250. mL of solvent, an absorbance of 1.018 is recorded.

77. ## geometry

given: chord AB is parallel to chord CD prove if two chords of a circle are parallel, the two arcs between the chords are congruent. Prove: arc AC is congruent to arc BD

78. ## physics

a 2.5 kg rifle fires a 20 g bullet at 400 m/s. What is the magnitude of the recoil velocity of the rifle?

79. ## physics

A moving electron passes near the nucleus of a gold atom, which contains 79 protons and 118 neutrons. At a particular moment the electron is a distance of 7.5 × 10−9 m from the gold nucleus. What is the magnitude of the force exerted by the gold nucleus

80. ## Math

Is (0,2) a orderd pair a solution of 4x - 3y = 6? Explain.

81. ## physics

a 2.5 kg rifle fires a 20 g bullet at 400 m/s. What is the magnitude of the recoil velocity of the rifle?

82. ## Physics (49)

An ice skater is gliding horizontally across the ice with an initial velocity of +5.33 m/s. The coefficient of kinetic friction between the ice and the skate blades is 0.0988, and air resistance is negligible. How much time elapses before her velocity is

83. ## Physics

the heating element of a coffee maker operates at 120 V and carries a current of 2 A. Assuming that the water absorbs all of the energy converted by the resistor, calculate how long it takes to heat .500 kg of water from room temperature 23 degrees C to

84. ## math

if a scale on a map is 1 in. = 250 miles, what would be the map distance if the actual distance between two cities is 1,000 miles?

85. ## Chemistry

for each of the following balanced chemical equations write all possible mole ratios. Mg+ 2HF---> MgF^2+ H^2

86. ## Finance

Corporate bonds issued by Johnson Corporation currently yield 8.5%. Municipal bonds of equal risk currently yield 6%. At what tax rate would an investor be indifferent between these two bonds? Round your answer to two decimal places. The answer I keep

87. ## Economics

Below is the production possibility information of small nations Arboc and Arbez, which can produce two goods, wheat, and coffee. The maximum quantity of each good is shown in the table below. Assume the two nations trade in a world containing many small

88. ## physics

What is the kinetic energy in J of a 66 g tennis ball approaching a tennis racket at 11.9 m/s?

89. ## physics

The picture shows a uniform ramp between two buildings that allows for motion between the buildings due to strong winds. At its left end it is hinged to the building wall , at its right end it has a roller that can roll along the building wall. There is no

90. ## Micro economics

Below is the production possibility information of small nations Arboc and Arbez, which can produce two goods, wheat, and coffee. The maximum quantity of each good is shown in the table below. Assume the two nations trade in a world containing many small

91. ## Chemistry

Calculate the amount of Citric acid monohydrate needed to make 100 mL of 0.1 M solution

92. ## physics

By what factor is the resistance of a copper wire changed when its temperature is increased from 20¢ªC to 120¢ªC? (the temperature coefficient of resistivity for copper = 3.9 ¢¥ 10‑3/C¢ª)

93. ## Chemistry

how to figure The grams of protein in 1 cup of soup that has 98 {\rm Cal} with 6 {\rm g} of fat and 8 {\rm g} of carbohydrate

94. ## algebra

Evaluate 5(11 + 22 - 10) – 19

95. ## physics

A wrecking ball is hanging at rest from a crane when suddenly the cable breaks. The time it takes for the ball to fall halfway to the ground is 4.36 s. Find the time it takes for the ball to fall from rest all the way to the ground.

96. ## Statistics

One of my classmates ask this question and it wasn't answered so now I am asking it and of course we are all struggling with no strong Math background Case 6.4 Maternal Serum Screening Test for Down syndrome Please keep in mind that I do not have a Math

97. ## chemistry

how to convert 4.8x10^5 hL to ml?

98. ## Economics

Below is the production possibility information of small nations Arboc and Arbez, which can produce two goods, wheat, and coffee. The maximum quantity of each good is shown in the table below. Assume the two nations trade in a world containing many small

99. ## Physics

If 200g of water at 20˚ C is combined with 100g of water at 80˚ C, what is the final temperature of the 200g of water? How do you do this??? steps by steps??

136. ## Math

Coould someone please let me know if I did this equation correctly. This question relates the topic of "Are you Sure It's Fat Free". To analyze the protein content I used 4 calories per gram of protein, rather than the 9 calories for gram fat. (Chunk Light

137. ## Stats- NEED HELP

According to the Census Bureau publication Current Population Reports, the probability distribution for household size (number of people per household, say X) in the United States is as follows. For the purpose of the next two questions, the experiment

138. ## Physics

A wire 3.00 m long and .450 mm2 in cross-sectional area has a resistance of 41.0Ω at 20 degrees C. If its resistance increases to 41.4Ω at 29.0 C, what is the temperature coefficient of resistivity?

139. ## Molecular and Electron geometry

Can anyone help me out with the differences between electron geometry and molecular geometry for SCl6? I think the molecular geometry is octahedral, but I'm not so sure for the electron geometry. Thanks :)

140. ## math-logic

Help with this please. I have to form the contrapositive of each and simplify negation using DeMorgan's rules. a) a->(b or c) my answer: contra(~b or~c)->~a simplified: ~b and ~c->~a b) (A and B)->(~q) my answer: contra (~A or~b)->q simplified:~a or ~b->q

141. ## chemistry lab

calculate the necessary amounts of solutes and solvent to make a 4 liter bottle of antifreeze that will have a 35 degree change in freezing point of water. solutes are Al2(SO4)3, KBr, Mg(NO3)2

142. ## chemistry lab

why would it not be useful to just use pure ethanil or pure ethylene glycol as aN ANTIFREEZE SINCE THEIR NORMAL FREEZING POINTS are -114.1 degrees celsius and -12 degrees celsius respectively

143. ## Earth and Physical Science

A 901 kg car is traveling north down a country road when a deer crosses in front of the car. By slamming on the breaks, the care is able to decelerate at 4.0 meters per second squared. What is the frictional force between the street and the car?

144. ## calculus

Let f(x) = [(2x2+4 x −70)/(x−5)] Show that f(x) has a removable discontinuity at x=5 and determine what value for f(5) would make f(x) continuous at x=5 Must define f(5)= I've been stuck on this problem for some time how would i do this one? Ty!

145. ## algebra

You have recently found a location for your bakery and have begun implementing the first phases of your business plan. Your budget consists of an $80,000 loan from your family and a$38,250 small business loan. These loans must be repaid in full within 10

146. ## critical thinking

help finding fallacies Water extinguishes fire. Oxygen is a part of water. Therefore oxygen extinguishes fire.

147. ## Chemistry

consider the following reaction mechanism 2A+B->B+C B+D->E+C What is the rate law for step 2 of this reaction?

148. ## math

on a map with a scale of 2 cm = 25 km, what would be the dimension of a 145 km by 80 km rectangle?

273. ## calculus

h(x)= tan(x)-x/x^3 given values 1 and 0.5

274. ## math

x^3-14x+8 / x-4

275. ## problem solving

A freight train travel 53.7 miles per hour. About how many miles did the freight train travel in 2.1 hours?

276. ## calculus

find the derivative of e^8e^x *8e^x

277. ## pharma

i m studying pharm.d(p.b).i m confuse about my project.give any idea

278. ## taxes

how long does it usually take to get your income takes back if you filed electronically and direct deposited?

279. ## English

Never belong, never guess, never confess is an example of: a. repetition b. parallelism c. rhyme scheme d. assonance I think it's B but I'm not sure.

280. ## chemistry

A person uses 1800 {\rm kcal} to run for 2.4 {\rm h}. Convert the energy for running to the following energy units: how many calories

281. ## criminal justice

Sorry about that. I will look at those right now. I have chosen the three prisons that I would like to provide the statistics for but it's just getting individual prison instead of an annual report. thank you,

282. ## math

how do i solve the following problems? a^5+6a^4+5a^3=0 t^5-256t=0 y^3-512=0 z=8(root)z+240

Hi! Just need confirmation. 3(sqrtroot)-27; My answer is -3 because 3 x 3 x 3 is 27. Thank you so much!!

284. ## Braingstorming

I am writting a contrast poem and I need a topic that has two veiwpoints

Is predator-prey the most important ecological relationship? Thanks everyone!

286. ## math

how many permutations are there for 4 numbers (0,2,3 and 5) adding up to 25 in 8 turns?

287. ## Writing

which would be correct: nowhere no where no wear

288. ## spelling

what is the easiest definition for menace?

290. ## Mathematics

For all real and positve numbers p and q, the following identity holds: (p^1/3 - q^1/3)(p^2/3 +(p^1/3)(q^1/3) + q^2/3) = (p - q) Does this identity still hold for negative p and/or q?

291. ## english

use injustice in a sentence

292. ## math

u/5=1.9 what is u

293. ## math

what is 3*10^6=

294. ## CRIMINOLOGY

what is one physical factor that may cause one a life of criminal behavior

295. ## math

x^3-14x+8 / x-4

296. ## MATH

5x-2y=4 x+2y=7

297. ## math

how do i simplify this; 8^-7/3