# R_scott

Newest questions and responses by R_scott
1. ## Science

posted on March 22, 2019
2. ## math/pre-calc

tmax lies on the axis of symmetry of the parabola ... -b / 2a ... -100 / (2 * -4.9)

posted on March 22, 2019
3. ## Science

a few need rework ... gravity seems to be a theme here Tides are caused by A) gravity. B) heat. C) waves.

posted on March 22, 2019
4. ## Physics

final energy = initial energy + energy from gravity 1/2 m Vf^2 = 1/2 m 16.0^2 + (m * 9.8 * 27.5) Vf^2 = 256 + (2 * 9.8 * 27.5)

posted on March 21, 2019
5. ## Math

yd^3 = 27 ft^3 3 ft^3 / (4 * 27 ft^3) = ?

posted on March 20, 2019
6. ## Precalculus

9/365 * 2 * π * 93 million

posted on March 20, 2019
7. ## math

1 foot by 1 1/2 foot

posted on March 20, 2019
8. ## Math

find the rate of fall ... (change in altitude) / (change in time) ... this is the slope of the line ... y = m x + b plug in one of the time/altitude points to find the y-intercept (b)

posted on March 20, 2019

you have three equations and three unknowns ... the unknowns are ... a, Vo, and So 144 = 1/2 a (.5^2) + Vo .5 + So 152 = 1/2 a (1^2) + Vo 1 + So 128 = 1/2 a (2.5^2) + Vo 2.5 + So solve the system for a, Vo, and So ... use the resulting equation to find max

posted on March 20, 2019
10. ## Math- Algebra

revenue = (500 - 20 x)(45000 + 5000 x) ... = 22500000 +1600000 x - 100000 x^2 xmax = -1600000 / (2 * -100000)

posted on March 20, 2019
11. ## Math

L + 2 W = 120 ... L = 120 - 2W area = L * W = (120 - 2W) * W = 120 W - 2 W^2 the maximum is on the axis of symmetry ... -b / 2a Wmax = -120 / (2 * -2) substitute back to find Lmax

posted on March 20, 2019
12. ## Physics

final speed = acceleration * time

posted on March 20, 2019
13. ## math

the radius is 10 cm (think about it) volume = π * radius^2 * height

posted on March 20, 2019
14. ## Algebra 2

from a z-score table the lower 20% is below ≈.842 σ

posted on March 20, 2019
15. ## Science (Physics)

reaction distance = speed * reaction time

posted on March 20, 2019
16. ## Math

v = 1/3 * area of base * height = 1/3 * π * r^2 * h the diameter is twice the radius

posted on March 20, 2019
17. ## Science

due to the Earth's axial tilt , constellations appear to move higher or lower in the sky, depending on the season

posted on March 20, 2019
18. ## Physics

heat = mass * specific heat * temperature change do the Al and Fe separately

posted on March 20, 2019
19. ## Science

average speed = 62.4 m / 4.20 s = (initial + final) / 2 change in speed = -5.60 m/s^2 * 4.20 s = initial - final solve the system for final

posted on March 20, 2019
20. ## maths

percent growth = [(change in height) / (starting height)] * 100%

posted on March 20, 2019
21. ## Math

a 4th order equation usually has 4 solutions b^4 + 2b^2 - 24 = 0 ... (b^2 + 6)(b^2 - 4) = 0 b^2 + 6 = 0 ... b = ± i √6 b^2 - 4 = 0 ... b = ± 2

posted on March 20, 2019
22. ## Chemistry

you're on the right track ... n is the total number of moles use the percentages to find the moles of each gas ... they have different heat contents

posted on March 19, 2019
23. ## math

2 * [(5 * 7) + (7 * 3) + (3 * 5)]

posted on March 19, 2019
24. ## Chemistry

the partial pressures are proportional to the mole fractions ... twice the moles, twice the partial pressure ... etc.

posted on March 19, 2019
25. ## Algebra 2

the maximum of the parabola lies on the axis of symmetry ... t = -b / 2a = -40 / -32 = 1.25 plug that into the height equation to find the max height

posted on March 18, 2019
26. ## math

umm ... you only got half of the surface area

posted on March 18, 2019
27. ## Trig

15% grade means that the tangent of the elevation angle is .15

posted on March 18, 2019
28. ## physics

work done by person ... 95.6 N * cos(35º) * .750 m work done by friction ... 75.5 N * .750 m the difference in the two work amounts is the kinetic energy of the box K.E. = 1/2 * mass * speed^2

posted on March 18, 2019
29. ## Physics

work = force * distance

posted on March 18, 2019
30. ## Newtonian Mechanics

1st part ... forces are m*g , distances are given 2nd part ... same forces ... distances are reduced by geometry ... distances equal to 1st part multiplied by sin(45º)

posted on March 18, 2019
31. ## Newtonian Mechanics

alternately use support 1 and support 2 as a fulcrum calculate the moments the mass of the beam acts in the center

posted on March 18, 2019
32. ## math

looks good

posted on March 18, 2019
33. ## Math

Volume = π r^2 h = 3.14 * 10^2 * 12 weight = V * 62.43

posted on March 17, 2019
34. ## Algebra

general circle equation ... (x - h)^2 + (y - k)^2 = r^2 circle centered at (h,k), with radius r

posted on March 17, 2019
35. ## Calculus

a trig substitution is used when calculating the integral as oobleck says, it's a standard trick

posted on March 17, 2019
36. ## math

yes

posted on March 17, 2019
37. ## math

the 2nd answer is correct ... use it to fix the 1st answer

posted on March 17, 2019
38. ## Math

s = smaller pump fill time ; b = bigger pump fill time s = b + 120 (144 / s) + (144 / b) = 1 [144 / (b + 120)] + (144 / b) = 1 144 b + 144 b + (144 * 120) = b (b + 120) 0 = b^2 - 168 b - 17280 convert answer to hours

posted on March 17, 2019
39. ## geometry

if the sum of the two smaller sides is ≤ the largest side ... a triangle cannot be made (won't close up)

posted on March 16, 2019
40. ## science

acceleration is changing speed, which falls under kinetic energy

posted on March 16, 2019
41. ## math

looks good

posted on March 15, 2019
42. ## math

the two lines mean "absolute value" ... just the number , no sign

posted on March 15, 2019
43. ## math

you plug the point into the equation and see if the equation is true x = 7 , y = 1

posted on March 15, 2019
44. ## Math

for each revolution of the tire , the bicycle travels ... 2.5 π ft revs = 5280 / (2 π)

posted on March 15, 2019
45. ## Algebra

it's arithmetic , so the missing term is the average of the ones on either side

posted on March 14, 2019
46. ## Algebra

9 ft * .8^3

posted on March 14, 2019
47. ## physics

by throwing the wrench away from the spaceship , she will give herself momentum towards the ship to me , this seems more like the 3rd law ... action/reaction

posted on March 14, 2019
48. ## math

0.275 x = 55 solve for x

posted on March 14, 2019
49. ## Math

parallel means the lines have the same slope ... their m's are equal y = 4 x + b ... through (1,6) plug in the point , and solve for b ... y = 6 , and x = 1

posted on March 14, 2019
50. ## science

try googling "rabbits in Australia"

posted on March 14, 2019
51. ## Physics

π/4 is the launch angle for maximum range on a level surface the vertical component of the launch velocity would be ... U √2 / 2 kinetic energy at launch is potential energy at peak ... U^2 / 4 = g h solve for h

posted on March 14, 2019
52. ## chemistry

1. moles = mass / atomic mass = 6.3 / 27 2. atoms = moles * Avogadro's number = moles * 6.02E23

posted on March 13, 2019
53. ## Math

what happened to the y that was already in the 1st equation?

posted on March 13, 2019
54. ## Science

acceleration = (change in speed) / (change in time) 2nd one looks good

posted on March 12, 2019
55. ## Algebra

x * .18 + (10 - x) * .40 = 10 * .20

posted on March 12, 2019
56. ## Math

1. yes ... it is the result of multiplying the equation by -1 2. no ... the left side can come from multiplication by -1 BUT ... changing a single sign in the right side polynomial is not a legitimate operation

posted on March 12, 2019
57. ## Science

_o_m_l_ VERY generous hint

posted on March 11, 2019
58. ## math

you are correct (90 - 75) / 75 = 20%

posted on March 11, 2019
59. ## Science

most meteors are chunks of comets that enter the Earth's atmosphere

posted on March 11, 2019
60. ## science

power = energy / time watt = joule / second

posted on March 11, 2019
61. ## science

speed = frequency * wavelength keep your units consistent ... m / km

posted on March 11, 2019
62. ## math

step 2 is incorrect subtracting 10 ... 2m^2 - 7m - 23 = 0

posted on March 10, 2019
63. ## chem

energy = specific heat * temperature change make sure all your units are compatible ... joules , grams , ºC , specific heat

posted on March 10, 2019
64. ## Stats

the z-score is the distance from the mean, measured in standard deviations points distance = z-score * σ

posted on March 10, 2019
65. ## Math

An becomes f(n) ... distributing the 6 ... 6n + 12 f(n) = 6 n + 12

posted on March 9, 2019
66. ## Math

n ≥ 2 looks like you're starting at 18, and adding 6 to each consecutive term An = 6 (n + 2)

posted on March 9, 2019
67. ## math

plug in the values 1, 2, 3, and 4 for n , and calculate the resulting terms

posted on March 9, 2019
68. ## Math

A = n B + k 15 = 2 n + k 45 = 8 n + k subtracting equations ... 30 = 6 n solve for n , then substitute back to find k

posted on March 9, 2019
69. ## Math

looks good

posted on March 9, 2019
70. ## mATH

draw a sketch and use the Pythagorean theorem BIG HINT ... it's a 3-4-5 triangle

posted on March 8, 2019
71. ## Math

how many fish did she catch? how many were trout? ... what fraction?

posted on March 8, 2019
72. ## Algebra

square the binomial and compare the results to find k (2x-3)^2 = 4x^2 - 12x + 9 (2x-3)^2 + k = 4x^2 - 12x + 13 check your calculations

posted on March 8, 2019
73. ## Science

read the "protist" article on wikipedia

posted on March 7, 2019
74. ## Algebra

there's only one rational number in the list ... you didn't pick it

posted on March 7, 2019
75. ## Physics

f = G * M1 * M2 / d^2 the masses are listed in Newtons, a force unit ... maybe a typo? the gravitational force equation uses mass ... is this happening on Earth? ... is g need for conversion?

posted on March 6, 2019
76. ## Physics

1st part ... d = 12 m/s * 30.0 s 2nd part ... ave speed = {12 m/s + [12 m/s + (1.5 m/s^2 * 8.00 s)]} / 2 ... d = ave speed * 8.00 s 3rd part ... top speed = 12 m/s + (1.5 m/s^2 * 8.00 s) ... d = top speed * 12.0 s add the displacements for the total

posted on March 6, 2019
77. ## math

start with easy and go to harder, if you have to assume a linear function ... y = m x + b when x is 0 , y is -1 ... so b is -1 when x is -2 , y is 9 ... 9 = -2 m - 1 ... 10 = -2 m ... m = -5 when x is 2 , y is -11 ... -11 = 2 m - 1 ... -10 = 2 m ... m = -5

posted on March 6, 2019
78. ## math

no input? arithmetic means add or subtract ... geometric is multiply or divide how do you get from one number to the next? what would be the next three numbers

posted on March 6, 2019
79. ## math

yes ... I do believe "clueless" substitute the values 1, 2, 3, and 4 for "n" in the given expression

posted on March 6, 2019
80. ## Science

from google ... abiotic ... "physical rather than biological; not derived from living organisms" if copper interferes with photosynthesis (a plant thing) , why B? maybe one person's rude , is another's tough love

posted on March 6, 2019
81. ## math

try plugging in one thru four for n

posted on March 6, 2019
82. ## Geometry

no givens...

posted on March 6, 2019

is there a relationship sign (like =, ≥, ≤, or something) missing?

posted on March 6, 2019
84. ## science

no diagram the 30º angle makes the most sense with the ceiling so the horizontal string force is ... m g sin(Θ) ... this is equal to the force of the electric field on the ball force = field strength * ball charge

posted on March 6, 2019
85. ## Science

where are they?

posted on March 5, 2019
86. ## math

no correction needed

posted on March 5, 2019
87. ## math

yes

posted on March 5, 2019
88. ## Math 6th grade

the + is between the number and two multiplication takes precedence (it happens first) over addition

posted on March 5, 2019
89. ## math

Damon ... look at the time stamps ... the answers are appearing almost simultaneously ... good group effort reality has to out shout stupidity

posted on March 5, 2019
90. ## math

the two spins are independent events P(vowel) = 1/3 P(K) = 1/6 multiply the probabilities

posted on March 5, 2019
91. ## math

P(red) = 8/43 P(blue) = 12/43 multiply the two probabilities (independent events)

posted on March 5, 2019
92. ## math

odds are different than probability ... favorable : unfavorable the probability of green is ... 6/11 the odds of green is ... 6:5

posted on March 5, 2019
93. ## Chemistry

looks good you might want to be aware of significant figures

posted on March 5, 2019
94. ## math

yes half of the numbers are even (divisible by 2)

posted on March 5, 2019
95. ## Algebra

there are eight cards in the hat , three of them with an I , five with another letter 3 I's , 5 not .. the odds of an I are 3:5

posted on March 5, 2019
96. ## Math

there are 6 ways to get doubles on the dice ... any of the six numbers on both dice ... 1-1, 2-2, 3-3, 4-4, 5-5, 6-6 there are 36 possible outcomes from rolling the dice ... any of the six numbers on one die, with any of the six numbers on the other die

posted on March 5, 2019
97. ## science

heat gained by water = heat lost by metal amount of heat = mass * specific heat * temperature change

posted on March 5, 2019
98. ## Math

it sounds like doubles on the dice...not any specific number her chances of winning are the same with both one number out of six on the wheel ... or 6 chances out of 36 with the dice

posted on March 5, 2019
99. ## Math

red (w/discount) ... \$18 per gallon blue (w/discount) ... \$20 per gallon (3 n * 18) + (2 n * 20) ≤ 500 54 n + 40 n ≤ 500 ... 94 n ≤ 500 ... n ≤ 5 15/47 3 n = 15 gal red ... 2 n = 10 gal blue

posted on March 4, 2019