# charles

Popular questions and responses by charles
1. ## physics

consider a vertical piston system. the piston has a 50g mass and a given radius of 3mm. what amount of pressure does the piston exert? ( use g==9.8 m/s^2 )

2. ## chemistry

Calculate the mass of oxygen (in mg) dissolved in a 5.00 L bucket of water exposed to a pressure of 1.13 atm of air. Assume the mole fraction of oxygen in air to be 0.21 and the Henry's law constant for oxygen in water at this temperature to be 1.3 x 10-3

3. ## Physics

You are given vectors A = 5.0i - 6.5j and B = -2.5i + 7.0j. A third vector C lies in the xy-plane. Vector C is perpendicular to vector A and the scalar product of C with B is 15.0. Find the x and y components to vector C. Answer key shows x component is

4. ## Physics

A baseball player leads off the game and hits a long home run. The ball leaves the bat at an angle of 30.0o from the horizontal with a velocity of 40.0 m/s. How far will it travel in the air? Working out please

5. ## Math

How many times does a palindromic number appear on a 12 hour digital clock between 12 midnight and 12 noon?

6. ## Math

Solve the equation sin2x=2cos2x, for 0 degrees

7. ## Chemistry

A piece of wood sinks in ethanol but floats in gasoline. Give a range of possible densities for the wood?

8. ## Math

3. The population of Columbus, Ohio, in 2014 was about 823,000. The population of the United States was about 319 million in 2014. (a) Write each population in scientific notation. (b) About how many times larger was the population of the United States

9. ## probability theory

3 students; A, B and C, are in a swimming race. A and B have the same probability of winning and each is twice as likely to win as C. Find the probability that B or C wins the swimming race. 3) Given three boxes as follows: Box A contains 3 red, 2 white

10. ## math

For some constants $a$ and $b,$ let $f(x) = \left\{ \begin{array}{cl} 9 - 2x & \text{if } x \le 3, \\ ax + b & \text{if } x > 3. \end{array} \right.$The function $f$ has the property that $f(f(x)) = x$ for all $x.$ What is $a + b?$

11. ## english

Choose the correct sentence pattern for the sentence below. I hereby declare Tuesday Shakespeare Day.

12. ## math

The given box plots show the number of text messages Paul and Sally received each day on their cell phones. Select the true statement. A. The interquartile range of Paul's data is less than the interquartile range of Sally's data. B. The median of Paul's

23. ## math

Thirty identical toothpicks were used to create the figure below. There are over 25 triangles in the figure. What is the fewest number of toothpicks that could be removed so that no triangles remain? The image is an equilateral triangle with base four.

24. ## math

a student claims that if a fair coin is tossed and comes up heads 5 times in a row, then according to the law of averages the probability of tails on the next toss is greater than the probability of heads. What is your reply?

25. ## math

two strips of fabric measure 14 2/3 inches and 20 7/8 inches in length. to form one length, the strips are sew together using 3/8 inch from each strip to make the seam. what is the final length of the fabric after the two strips are sewn together.

26. ## chemistry

An increase in the average kinetic energy of a sample of copper atoms occurs with an increase in a. concentration b. pressure c. volume d. temperautre

27. ## mathematics

solve :log (12x-10)=1+log2(4x+3)

28. ## math

Melina walked her dog 2 1/5 miles. Cathy walked her dog 1 3/4 times as far as Melania did. How many more miles did Cathy walk her dog?

29. ## Calculus-Derivatives

How is 6#sin(#x-1)/cos^3(#x-1) the derivative of f(x)= 3sec^2(#x-1)? #= Pi (I coulnd't find the symbol...sorry.)

30. ## math

Suppose that $n$ is a positive integer such that in base $7$, then $n$ can be expressed as $\overline{ABC}_7$, and in base $11$, then $n$ can be expressed as $\overline{CBA}_{11}$. Find the largest possible value of $n$ in base $10$.

31. ## math

A man walks due west for 4km. He then changes direction and walks on a bearing of 179 until he is south-west of his starting point.How far is he then from his starting point?

32. ## algebra

{distinct letters in the word food}

33. ## math

Let $A$ and $B$ be real numbers such that $\frac{A}{x-5}+B(x+1)=\frac{-3x^2+12x+22}{x-5}$. What is $A+B$?

34. ## Physics

Find the sum of vectors A=5m

5x/9-11=-51

36. ## Science

Identify two segments parallel to HG

37. ## math

Navin from Mauritius, Luka from Croatia, and Ian from Botswana are chatting in the lobby of a youth hostel discussing their part-time jobs. They learn that Navin makes 160 rupee per hour, Luka makes 25 kuna per hour, and Ian makes 34 pula per hour. If one

38. ## chemistry

A 0.109g sample of a pure gaseous compound occupies 112ml at 100degrees and 750torr: what is the molecular weight of the compound. ANS=(30.2g,mol). Please I need the solution

39. ## Math

A toy company manufactures miniature cars. They sell miniature sports cars in a box. They sell 12 miniature trucks in a box. Mrs. Murphy wants to buy an equal number of sports cars and trucks for the Boys and Girls Club. What is the least number of

40. ## math

A woman wants to take her fox, chicken, and bag of corn across the river in her canoe. The canoe can hold only one thing in addition to the woman. If left alone, the fox would eat the chicken, or the chicken would eat the corn. How can the woman take

41. ## Chemistry

A shiny gold colored car of metal weighting 57.3g has a volumes of 4.7cm^3. Is the bar of metal pure gold?

42. ## Physics

It takes a runner 2 h, 43 min, 57 s to run a marathon. If the distance of a marathon is 42.2 km, what is the average speed of the runner?

43. ## Chemistry

If 84.1 g of sodium hydroxide are reacted with 51.0 g of aluminum in the following equation: 2NaOH + 2Al + 2H2O --> 2NaAlO2 + 3H2 a) what mass of excess reactant remains? b) what mass of water would react?

44. ## math

In order to pass a physical education class at a university, a student must run 1.0 mi in 12.5 min. After running for 10.0 min (assume constant speed), she still has 510 yd to go. What constant acceleration does she need over the final 510 yd in order to

45. ## Logic

Choose the pair of words/phrases among the choices that exhibits the same logical relationship as the words/phrases in the following pair. heavy : weight dry : wet feather : scale #hot : temperature color : size I placed a # next tom my answer.

46. ## Chemistry

The density of water is 1.0 g/mL. How many deciliters of water will fill a 0.5-L bottle?

47. ## physics

a sphere of radius r moving with velocity v through a fluid experiences a retarding force f given by F=6r^yv^zn^x where n is the viscosity of the liquid. use the method of dimensions to find the values of x,y,and z.

48. ## math

4/5 * 3/4 = =16/20 * 15/20 =240/20 =12 is this right?

49. ## Math

Elbert wants to plant grass seed in his backyard. His yard is shaped like a rectangle that is 6 meters by 7 meters. He plans to use a cup of seed for every square meter in his yard. How many cups of grass seed will he need?

50. ## Math

Serena has a square-shaped garden. She wants to put a fence around the outside of the garden. One side of the garden is 8 feet long. How many feet of fence will she need?

51. ## Math/Trig

Which logarithmic equation is equivalent to L^m = E 1) LogL E = m 2) logE L = m 3) logm E= L 4) logE m= L

52. ## Trigonometry

This is a logs question If u=x/y^2, which expression is equivalent to log u? 1) log x + 2 log y 2) 2(log x- log y) 3) 2(log x + log y) 4) log x- 2 log y

53. ## Electronics

With a carrier voltage of 80Vp-p and %m at 100 what is Vm,Vmax,Vmin,Vusb,Vlsb

54. ## Mathematics

The 12th term of an AP is -41, given that first term is 3. Find the 20th term

55. ## math

solve 7x = 42 show your work help plz

56. ## math

There are numbers A and B for which A/(x-1)+ B/(x+1)=(x+2)/(x^2-1)for every number x≠±1. Find B.

57. ## math

What is the minimum value of $y$ if $y=3x^2+6x+9?$

58. ## Physics

A man walks 3km E and then 4km N. What is his resultant displacement?

59. ## Physics

Find the magnitude of the dot product of the two vectors B=6i+j+2k, D=-1+3j. What is the angle between B and D

60. ## math

A jar contains 133 pennies. A bigger jar contains 1 2/7 times as many pennies. What is the value of the pennies in the bigger jar

61. ## General Physics

A force Fx acts on a particle. The force is related to the position of the particle by the formula Fx = (5.9 N/m3) x3. Find the work done by this force on the particle as the particle moves from x = 0.9 m to x = 22 m. Answer in units of J

62. ## Math

A mother of triplets wants to buy gum balls the machine has two colors how much will it cost to get three gum apps the same color ?

63. ## arithmetic

first term and larst term of a geometric progression is 42.if the forth term is greater than the second term by 168, find the first term.the forth term.

64. ## Physics

On a part-time job, you are asked to bring a cylindrical iron rod of length 91.9 cm and diameter 2.70 cm from a storage room to a machinist. Calculate the weight of the rod, w.

65. ## stat

the time between unplanned shutdowns of a power plant has an exponential distribution with a mean of 20 days. Find the probability that the time between two unplanned shutdow is a) less than 14 days B) more than 21 days c) less than 7 days

66. ## physics

a drop of oil of volume 000000000•1m spreads out on water to make a circular film of radius 0•1m what is the thickness of the film?

67. ## History

I have an important essay about the three g's on god gold and glory. I need a hook, background, thesis statement. Thank You

68. ## math

Thirty identical toothpicks were used to create the figure below. There are over 25 triangles in the figure. What is the fewest number of toothpicks that could be removed so that no triangles remain? Triangle has base 4 and height 4

69. ## Geometry

Two pyramids are similar. The surface area of the first is 250 and the surface area of the second is 22.5. The heights of the pyramids are in a ratio of _ : _ The volumes of the pyramids are in a ratio of _ : _ Two pyramids are similar.

70. ## Math

A table tennis ball is dropped from a height of 5ft. The ball rebounds to 60% of its previous height after each bounce. Write an infinite geometric series to represent the distance that the ball travels after it initially hits the ground. (hint, the ball

71. ## Algebra 2

Water towers are tall to provide enough water pressure to supply all of the houses and businesses in the area of the tower. Each foot of height provides 0.43 psi (pounds per square inch) of pressure. a. Write a sequence for the pressure in psi for each

72. ## English 12

One goal of America Recycles Day is to raise awareness of the growing landfill problem. Which of these phrases is the complete infinitive phrase in the sentence?

73. ## math

How many terms of the arithmetic sequence 88, 85, 82, . . . appear before the number -17 appears?

74. ## math

The length by the width of Roxie's photo is 24 cm long and 14 cm wide. In order to make a photo that will fit into a wallet, the photo needs to be reduced to a length of 7 cm. Determine the width of the wallet size photo.

75. ## Science

A 0.5kg mass connected to a light spring of constant 20N/M occilates on a frictionless track. Calculate the total energy of the system

76. ## math

I need help making this question into a equation? A cable television company charges $15 plus$5 each for extra services and now write an equation to show how much a person would pay for television if they had x number of extra services?

77. ## Physics

If D=7i-3j+2k. Find the magnitude of D

78. ## Physics

If D=7i-3j+2k and E=4i+5j-3k. Find the scalar product of D.E

79. ## Physics

What is the total time of flight of an object projected vertically upwards with a speed of 30m/s? (g=10m/s^2

80. ## physics

The vertical and horizontal component of the initial velocity of a projectile are 36m/s and 64m/s. Find the initial velocity and angle inclination

81. ## maths

A rectangle of length y m and breadth 4 m less than the length. What is the perimeter??

82. ## physcis

a girl throws a ball vertically upward with a speed of 20 ft/sec from the roof of a building 60 ft high.(a)how long will it take the ball to reach the ground? (b)what will its speed be when it strikes the ground?