Posts by Scott

Total # Posts: 3,876

  1. geometry

    the cable is the hypotenuse of the right triangle formed by the cable, pole and ground. (height of attachment) / (cable length) = sin(60º) h / 20 m = ?3 / 2
  2. math

    the max height is on the axis of symmetry of the parabola tmax = -b / 2a = -56 / (2 * -1.9) solve for the time at max ... plug the time into the height equation to find max height
  3. Math

    the ratio of the areas is the square of the ratio of the sides ... 3^2 : 5^2 ... 9 : 25 25 a / 9 = a + 576
  4. maths

    a. 3 , -1/3 , 3 , 4 , -1/4 , 3/4 , -4/3 , -1/3 , 3 b. R , T , T c. R , T , R , T , T , R , T , T d. R , T , R , T , T , R , T , T , R , T , T , R , T , T , R , T , T , R , T , T
  5. Math

    looks good
  6. Chemistry

    Np thanks scott for the help
  7. Chemistry

    okay ... I didn't make the stp correction for the O2
  8. Chemistry

    First i did (1 atm x 2 L) / (K(constant) x 298.15K) = 0.081745mol Then i did (0.081748 mol O2) x (8 mol SO3 / 12 mol O2) x (80.0632 g SO3/mol) = 4.36 g SO3
  9. Chemistry

    your number seems low 4.76 g ?
  10. Chemistry

    Just want to double check, I ended up getting 4.363g SO3
  11. Chemistry

    moles of S ... 8 * 25 / 256.56 moles of O ... 2 * 2.0 / 22.4 O will be the limiting reactant be aware of significant figures
  12. Chemistry

    If 25.0 g S8 (molar mass = 256.56 g/mol) is made to react with 2.0 L O2 at 25 oC and 1.0 atm, what is the maximum amount (in grams) of SO3 produced?
  13. math

    the 20 pieces allow you to select all of one kind, or any combination 20C5
  14. math 7 grd

    if you google "cylinder minimum surface area" , you will find that a can whose height is equal to its diameter is the minimum surface area a "most compact" sphere fits inside, touching the cylindrical wall and the two ends
  15. algebra

    the height forms a right triangle with the slant height as the hypotenuse and half of the base diagonal as the other leg (height)^2 = (slant height)^2 - (half of base diagonal)^2 h^2 = 83.3^2 - (10.8 ?2)^2
  16. Chemistry

    heat ice to 0ºC ... 10.0 g *10.0 ºC * 2.09 J/gºC melt ice ... 10.0 g * 334 J/g heat water to 100ºC ... 10.0 g * 4.184 J/gºC * 100.0 ºC boil water ... 10.0 g * 2.23 kJ/g heat steam to 115ºC ... 10.0 g * 1.84 J/gºC * 15.0 ºC add the ...
  17. algebra

    4 = a b^4 8 = a b^16 dividing ... 2 = b^12 ... b = 2^(1/12) substituting ... 2^2 = a 2^(1/3) ... a = 2^(5/3)
  18. algebra 2

    v = 20000 (1 - .10)^y
  19. physics

    the refractive index (n) for water is ... 4/3 ... it is 1 for air (n air) * sin(?i) = (n water) * sin(?r) ... this is Snell's law
  20. Physics 2

    crest to trough (half wavelength) time is 3.0 s , so 6.0 s for a full wavelength the wavelength is 8.0 m wave speed is ... 8.0 m / 6.0 s
  21. Math

    Yeah I'm sure 5 is there because it's power cube of 5sqrt
  22. Math

    Solve? 5 sqrt 2^3x * 64^2x+2 =32768^x
  23. Math

    1. a) value = (23000 * .85) (1 - .07)^(2023 - 2018) b) 5000 = (23000 * .85) (1 - .07)^(year - 2018) 2. a) 500 = 800 (1 - .035)^(year - 2017) b) 800 = 1200 (1 - .035)^(2017 - year)
  24. Math

    1. A car is worth $23000 in Jan 2017 in the first year the car depreciates by 15 percent per annum and then 7 percent every year after that. a) what will the car be worth in Jan 2023? b) when will the car be worth $5000? 2. In 2017 the population of a certain animal in your ...
  25. Math

    1. 2.34 = x (1/2)^(36 / 8.14) ... log(2.34) - [(36 / 8.14) log(1/2)] = log(x) 2. .23 = (1/2)^(t / 64.9) ... log(.23) = (t / 64.9) log(1/2) 3. x = 4000 * 5^(48 / 6)
  26. Math

    1. Iodine-131 is used to find leaks in water pipes it has a half life of 8.14 days. If 36 days have passed and there is now 2.34g left. What is the initial amount? 2. Sr-85 is used in bone scans and has a half life of 64.9 days. If there is 23 percent of the sample remaining ...
  27. science (physics)

    it starts from rest (vertically), and is accelerated by gravity 180 m = 1/2 g t^2 ... g = 9.8 m/s^2
  28. Chemistry

    Thank you
  29. Chemistry

    If a gas effuses 1.618 times faster than Kr (molar mass = 83.8 g/mol) what is the molar mass of the gas?
  30. Algebra

    J - 6 = 5 (D - 6) + 2 ... J - 6 = 5 D - 28 J + 6 = 2(D + 6) + 11 ... J + 6 = 2 D + 23 5 D - 22 = 2 D + 17 solve for D , substitute back to find J
  31. Algebra

    S + L = 7 .2 S + .3 L = 1.8 ... S + 1.5 L = 9
  32. Science (Chem)

    find moles of KCl ... 10.00 g / molar mass volume = moles KCl / 0.150 ... multiply by 1000 for mL
  33. Algebra

    R = 2 P R + 4 = 3 (P - 3) substituting ... 2 P + 4 = 3 P - 9
  34. math

    3x^2 + 12x = -14 x^2 + 4x = -14/3 x^2 + 4x + 4 = -2/3 (x + 2)^2 = -2/3
  35. math

    2y^2 + 12y = -3 y^2 + 6y = -3/2 y^2 + 6y + 9 = 15/2 (y + 3)^2 = 15/2
  36. math(aka) algebra

    C looks good
  37. math(aka) algebra

    the domain means all possible values of x the range means all possible values of y the answers don't match the question
  38. Math

    f = (2/5) (i - 3i/10 - 3i/8 - i/6) ... find f in terms of i 469 = 3i/8 + f ... substitute for f , then solve for i s = 3i/10
  39. math

    [20 / (j - 3)] + [20 / (j + 3)] = 7 20 j + 60 + 20 j - 60 = 7(j - 3)(j + 3) = 7 j^2 - 63 0 = 7 j^2 - 40 j - 63 use quadratic formula to find j
  40. Math

    arrange in order ... 4 , 6 , 8 , 10 , 11 , 12 , 18 , 20 8 values , so two per quartile the quartile "boundries" are the average of the numbers on either side ... 6 is the last value in the 1st quartile , 8 is the 1st value in the 2nd quartile ... so the 1st quartile ...
  41. Physics

    weight = 700N + 500N measuring distance (d) from the 500N end ... d(700 + 500) = 2 * 700
  42. math

    26 letters in the alphabet , 10 numbers 26 * 9 * 10^7
  43. Physics

    130 dB is equivalent to 10 w/m^2 the area of the eardrum is ... ? r^2 = ? (8.5E-3)^2 m^2 = 2.27E-4 m^2 10 w/m^2 * 2.27E-4 m^2 = 2.27E-3 W = 2.27 mW (milliwatts)
  44. Physics

    have you learned about significant figures did you notice the FYI
  45. Physics

    what is incorrect?
  46. Physics

    the power is evenly distributed over the surface of a sphere with a radius of 19.3 m 46673.5 W / (4 ? 19.3^2) m^2 calculate watts/m^2 calculate the area of the eardrum FYI ... be aware of significant figures
  47. geometry

    as the number of sides on a regular polygon increases, it becomes more like a circle
  48. Algebra

    G = R + 20 G - 5 = 5 (R - 5) substituting ... R + 15 = 5 R - 25
  49. Algebra

    10 t + u = 7t + 7u t = u + 3 substituting ... 11 u + 30 = 14 u + 21
  50. Math

    K = 5 M K + M = 300 substitution is probably the best solution method
  51. Chemistry

    30 moles H from NH3 ... 10 moles H from H2SO4 40 moles H yields ? moles H2
  52. physics

    A 3 kg block is attached to an ideal spring with a force constant k=200 N/m. The block is given an initial velocity in the positive direction of magnitude u= 12 m/s and no initial displacement (xi=0). Find a) the amplitude, b) the phase angle, and c) write an equation for the ...
  53. Physics

    Two people carry a heavy electric motor by placing it on a light board 2 meters in length. One person lifts at one end with a force of 700 N, and the other lifts the opposite end with a force of 500 N. What is the weight of the motor, where along the board is its center of ...
  54. science

    destruction, fragmentation, and poaching all sound pretty negative ... don't you think?
  55. Physics

    sphere volume ... 4/3 ? r^3 surface area ... 4 ? r^2 s.a. = k v^(2/3) Area209 / Area1 = k[209^(2/3)] / k[1^(2/3)] = 209^(2/3)
  56. Physics

    angular velocity = 2 ? / 35 rad/min
  57. Algebra 1--quick question

    28/35 or 80% are ? 7.5 i think that's the definition of percentile
  58. Algebra

    yes
  59. BC Calculus

    x = length , y = width x + 2y = 800 ... x = 800 - 2y area = x y = y (800 - 2y) = -2 y^2 + 800 y setting the 1st derivative equal to zero will show the max value -4 y + 800 = 0 ... y = 200
  60. Math (Please help ASAP!!)

    sure, let's all chime in correlation coefficient values are ... -1 ? cc ? 1 a greater absolute value means better correlation values close to zero (like -.015) indicate very little correlation
  61. Science

    im not sharing my knowledge but i would recommend a google search
  62. math

    B = 5 a - 1 H = 5 a + 1 V = 4 a + 5 there is not enough information to determine (a) , so there are an infinite number of solutions
  63. science

    MUCH better
  64. science

    #1 looks good #2 and #3 need some research
  65. math 11

    the graph is a line one side is the true region, the other side is the false region 5 water and 7 OJ lies in the false region
  66. Algebra

    sorry, my train of thought derailed ... the vertex is on the axis of symmetry ... the equation (for the axis) is ... x = -b / 2a ... in this case ... x = -(-2.6) / (2 * .2) = 6.5 min # of dulcimers is ... 650 solve C(650) to find the min ave cost of dulcimers
  67. Algebra

    the graph of a quadratic equation is a parabola when you are looking for a minimum, the parabola generally opens upward, with a minimum at the vertex ... this means a negative coefficient for the 2nd order (squared) term ... this is not the case with the equation you have ...
  68. Algebra

    the general equation is ... y = ax^2 + bx + c plug in the three points to generate three equations in a, b, and c solve the system of equations for the three coefficients 1st one ... -3 = a(0)^2 + b(0) + c
  69. Trig

    you could resolve the two legs into north-south and east-west components, and add them
  70. math

    by Pythagoras ... x^2 + (x + 3)^2 = (x + 6)^2 2x^2 + 6x + 9 = x^2 + 12x + 36 x^2 - 6x - 27 = 0 ... (x + 3)(x - 9) = 0
  71. Calculus

    141.96 may have too many significant figures try rounding to three digits
  72. Calculus

    D^2 = Pn^2 + Pe^2 + 2^2 use implicit differentiation ... 2 D dD/dt = 2 Pn dPn/dt + 2 Pe dPe/dt ?(15^2 + 10^2 + 2^2) dD/dt = 15 * 55 + 10 * 175
  73. Pre-Calculus

    the length of the ramp is the hypotenuse (a) sin(?) = 225/325
  74. Pre-Calculus

    the base of the triangle is the east-west line between the rangers the angle at the 1st ranger is ... 90º - 32º the angle at the 2nd ranger is ... 90º - 49º the 3rd angle is between the ranger stations (from the fire) ... this distance is 13 mi use the law ...
  75. Math

    square pyramid
  76. math

    dividing by ? ... r^2 = A / ? taking square root ... r = ?(A / ?)
  77. Math

    tetrahedron
  78. Science

    google potassium-argon dating
  79. math

    the dB sale is logarithmic the intensity of A is ... 10^[(54 - 32) / 10] times as intense as B
  80. Math

    so the log of the concentration is ... -11.0 logarithms are exponents ... for "common" logs (no base given), the base is 10 [H+] = 10^-11
  81. physics - please help me!

    thanks for catching that, Bob a = - 4.9 , b = v sin(50º) , c = -16 t = {-b ± ?[b^2 - (4 a c)]} / (2 a)
  82. physics - please help me!

    the vertical and horizontal times of flight must be the same for the windows position ... 27 m horizontal, and 16 m vertical horizontal time ... distance / velocity ... t = 27 m / v cos(50º) vertical time ... 16 m = 1/2 g t^2 + v sin(50º) t ... 0 = 4.9 t^2 + [v sin(...
  83. Math

    google will do units conversion ... enter "liters to gallons" the question says "about" ... a liter is about a quart ... there are four quarts in a gallon
  84. physics - help!

    find the initial vertical velocity ... 22 m/s * sin(35º) gravitational acceleration (g = 9.8 m/s^2) will slow the ball to a stop (vertically) ... the ball will then fall back down ... time up = time down time = velocity / acceleration flight time = 2 * [(initial vertical ...
  85. maths

    (a + 3) / 2 = 5 (b + 4) / 2 = -2
  86. Chemistry

    find the moles of KBr ... 5.00 g / molar mass KBr find energy change ... 25.0 g H2O * specific heat H2O * temperature change H2O
  87. physics

    momentum is conserved so the momentum of the train is "distributed" to the train/box car just because your calculator displays them, there are NOT 11 sig figs in the answer
  88. Math

    each of the 8 points is connected to the other 7 8 * 7 = 56 ... BUT ... a line from A to B is the same as a line from B to A ... so 56/2
  89. Math

    need more information
  90. Math

    w = t + b + h t = 9 h = t + b/2 ... h - 9 = b/2 ... 2 h - 18 = b b = t + h ... b = h + 9 2 h - 18 = h + 9 ...solve for h , then substitute back to find b
  91. MATHh

    let w equal the width of the frame the frame is made up of four pieces ... 20+w long, and w wide 4 * w * (20 + w) = 20 * 20 / 5 ... 80 w + 4 w^2 = 80 ... w^2 + 20 w - 20 = 0 use the quadratic formula to find w
  92. Algebra 1

    time = distance / rate (d / 14) + (d / 20) = 3 2/5 using LCD ... (10 d / 140) + (7 d / 140) = 3 2/5 17 d = 476
  93. physics

    momentum is conserved 2285 * 13 = (2285 + 2465) * v 13 - v = ?
  94. Algebra

    when x = -4, there is a zero in the denominator (vert) as x goes to ±?, the 1st term of the expression goes to zero, leaving -6 (horiz)
  95. Algebra

    f(x) = [(x + 3)(x - 3)] / (x - 3) when x = 3, there is a zero in both the numerator and denominator (hole) find f(3) to get the coordinates
  96. Physics

    one of the parameters affecting refraction is the angle of the incoming ray this "angle of incidence" is measured relative to a normal to the surface if the incident ray is perpendicular to the medium, then the angle of incidence is zero; and there is no refraction
  97. Physics

    c / (speed in medium)
  98. Physics

    google "critical angle"
  99. math

    K and A are their present ages K - 4 = 2 (A - 4) K = A + 6 substituting ... A + 6 - 4 = 2 A - 8 solve for A, then substitute back to find K
  100. Maths

    1 m per move up to 8 m ... 8 moves on the 9th move, it reaches the top and doesn't slip back
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