# 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

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

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

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

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

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

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 / ?)

tetrahedron

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

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

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

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)

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
1. Pages:
2. 1
3. 2
4. 3
5. 4
6. 5
7. 6
8. 7
9. 8
10. 9
11. 10
12. 11
13. 12
14. 13
15. 14
16. 15
17. Next>>