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March 26, 2017

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Posts by Scott

Total # Posts: 1,994

Science
as the stone travels upward, its kinetic energy becomes potential energy the potential at the top is equal to the kinetic at the bottom ... e = 1/2 m v^2 = m g h ... h = ?[v^2 / (2 g)]
February 5, 2017

Pre-Calculus
?[389^2 + (389 + 50)^2]
February 5, 2017

science
h = -1/2 g t^2 + 7 t + 55 h is zero when the bottle hits the ground 0 = -4.9 t^2 + 7 t + 55 you want the positive solution
February 5, 2017

Algebra2
30 * (54/42)^2 * (26/85)
February 4, 2017

physics
do they start timing at a crest? there are 19 wavelengths between 20 crests
February 4, 2017

Chemistry
K.E. = 1/2 m v^2 look up the mass of the electron (in kg), and solve for v
February 4, 2017

Math
f = t - 20 j = 2f = 2t - 40 p = 3j = 6t - 120 9t - 180 = 340 solve for t, then substitute back
February 3, 2017

Science
Elodea uses photosynthesis to convert carbon dioxide and water into oxygen and carbohydrate the most bubbles should be in the carbon dioxide enhanced sample the degassed sample should have no bubbles the oxygen enhanced sample should be somewhere in between
February 3, 2017

math
b = 20000 (1 + .07)^6
February 3, 2017

math
this seems to be two questions 1st b + g = 30 b = g + 4 substitute to find solution 2nd 4 + 1 = 5 30 / 5 = 6 30 - 6 = 24 there are 24 of one and 6 of the other
February 3, 2017

Math
f + s = 45 s - f = 37 adding equations ... 2 s = 82
February 3, 2017

Science
velocity = distance / time
February 3, 2017

Science 6th grade
they are more massive (heavier) than the inner planets; and their greater gravities allow them to hold the lighter gasses
February 2, 2017

Maths
[(1.025 x) - 1000] * 1.025 = 23517.6
February 2, 2017

Math
(6 x)^2 + [5 (x - 4)]^2 = (7.5 x)^2
February 2, 2017

Math
f + s = 11000 ... 8 f + 8 s = 88000 5 f + 8 s = 75250 subtract equations to eliminate s 3 s = 12750
February 1, 2017

Trigonometry
theta is a Quad IV angle with a sine of -3/5 find cos, tan, sec, csc and cot
February 1, 2017

algebra
[.30(8080 - x)] + [1.0(x)] = .80(8080)
February 1, 2017

MATH
yes ... not to confused everything gets raised to the power
February 1, 2017

algebra
x + y = 48 x / 3 = (y / 6) + 5 ... 2x = y + 30 ... 2x - y = 30 add equations to eliminate y substitute back to find x
February 1, 2017

math
40000 L takes 30 pump-hr so 60000 L takes 45 pump-hr ... one and a half times as much 45 pump-hr / 9 pump = ?
January 30, 2017

trig
use the "Law of Cosines"
January 30, 2017

math
you have one equation and two unknowns there is no "unique" solution the solution is a line
January 30, 2017

Chemistry
find the energy (heat) for each step ... the mass of H2O is constant warm ice to 0ºC melt ice warm water to 100ºC boil water warm steam to 112ºC
January 30, 2017

physics
v initial = 100000 m / 3600 s v final = 0 v ave = (vi + vf) / 2 time = .85 m / (v ave) accel = vi / time
January 29, 2017

math
p = e + 10 15 p + 22 e = 446 15 (e + 10) + 22 e = 446 37 e = 296
January 29, 2017

Math
the normal line is perpendicular to the tangent the slope of the tangent is the 1st derivative normal slope ... -2 tangent slope ... 1/2 1/2 = 4 x^3 ... 1/8 = x^3 ... 1/2 = x point ... (1/2 , 1/16) equation ... y - 1/16 = -2 (x - 1/2)
January 29, 2017

Probability, Stats
d = defective , n = not defective this is a binomial distribution ... a battery is or isn't 100C2 * .985^98 * .015^2
January 29, 2017

physics
assuming flat ground distance = v^2 * sin(2?) / g
January 29, 2017

physics
235 - 92
January 29, 2017

Pre Cal 12
1400 = 900 [1 + (i / 4)]^(12 * 4) log(14 / 9) = 48 log[1 + (i / 4)]
January 28, 2017

Math -
multiplying 2nd equation by 2 ... 12x + 14y = 20 subtracting equations (to eliminate y) ... 4x = -4 solve for x, then substitute back to find y
January 27, 2017

Pre Cal
the sides are in the same ratios as the sines of their opposite angles a = c * [sin(A) / sin(C)]
January 27, 2017

Geometry
find the distance between two points on the original figure, and the same points on the dilated figure the ratio of the distances is the scale factor
January 26, 2017

Math
d = r * t twice the speed means half the time
January 26, 2017

science
the molar mass of CaO is ... 40 + 16 so 44 g contains ... [44 / (40 + 16)] moles
January 26, 2017

Chemistry
warm the ice from -15ºC to 0ºC melt the ice warm the water from 0ºC to 100ºC boil the water heat the steam to 114ºC each step has its own heat input
January 26, 2017

math
the system of equations has no solution ... the lines are parallel
January 25, 2017

Chemistry
a mL is a cm^3 a foot is ... 2.54 * 12 cm 1 ft^3 Hg ... mass = (2.54 * 12)^3 * 13.6 g multiply by g to find the weight
January 25, 2017

Maths
a1, a1 + 36, a3, a3 + 900 (a1 + 36) / a1 = (a3 + 900) / a3 1 + (36 / a1) = 1 + (900 / a3) a3 = r^2 * a1 36 = 900 / r^2 ... 6 r = 30
January 25, 2017

Math
50000 = 30000 (1 + i)^18 log(5/3) = 18 log(1 + i) .012325 = log(1 + i)
January 25, 2017

math
A = 100 * (1 + .03)^30
January 25, 2017

maths
a = 40 m/s / 2 ms = 20000 m/s^2 f = m a = .05 kg * 20000 m/s^2 answer is in Newtons
January 25, 2017

Math
divide the expression by the factor that will leave a quadratic that you can use the formula on
January 24, 2017

Physics
1) no horizontal acceleration ... v = 17 m/s * cos(34º) 2) same vertical velocity as at launch, except in opposite direction ... v = 17 m/s * sin(34º) ... downward 3) the flight time is twice the initial vertical velocity, divided by gravitational acceleration 4) the...
January 24, 2017

physics
mass * temp change * specific heat make sure the specific heat value is in Joules
January 24, 2017

Geometry
5 b + 5 b + b = 121
January 24, 2017

Physics
you're not accelerates to 12 m/s, then travels for 20 s ... that's 240 m, plus the acceleration distance d = 1/2 a t^2
January 24, 2017

Geometric Progression.
(x + 9) / x = (x + 22.5) / (x + 9) x^2 + 18 x + 81 = x^2 + 22.5 x 81 = 4.5 x a1, a2, 18, 27, 40.5
January 24, 2017

Physics/Energy
work = m g h the time is only a factor for power calculation
January 24, 2017

Math
60x + y = 87.15 subtracting equations ... 30x = 33.60 substituting ... 33.60 + y = 53.55 ... y = 19.95
January 22, 2017

Matha
compounding period?
January 22, 2017

Physics
KE = 1/2 m v^2 m = .02 kg v = (200000 / 3600) m/s answer is in Joules
January 22, 2017

physics
1/2 m v^2 = m g h h = v^2 / (2 g)
January 22, 2017

Physics
the same depth means the same pressure at the bottom the forces are equal
January 22, 2017

science
K.E. is proportional to the square of the velocity this means that the energy change from 80 kph to 70 kph is greater than the change from 10 kph to zero use (1/2 m v^2) to find the energies the lost energy (from braking) is usually frictional (heat)
January 21, 2017

Maths
each cut results in a cake that is 3/4 of the size before the cut starting with a whole cake (1) after 3 cuts ... 1 * (3/4) * (3/4) * (3/4)
January 21, 2017

physics
his energy at the bottom is the change in potential energy, minus the work of friction ... m * g * h - 520 * h ... E = (88 kg * 9.8 m/s^2 - 520 N) * 5.9 m his velocity is (from K.E. equation) ... v = ?(2 * E / m) while he is slowing down, his average velocity is ... (v + 0) / ...
January 20, 2017

math
2 x^2 + 13 x - 84 = 0 use the quadratic formula
January 19, 2017

science
the molar mass of sulfur is 32.1 g there are 6.02E23 atoms in a mole of sulfur (10.0 / 32.1) * 6.02E23
January 19, 2017

Chemistry
1. -3 means 3 "extra" electrons ... this element is atomic number 7 2. +2 means 2 "lost" electrons ... this element is atomic number 20 3. column 2, row 3
January 18, 2017

math
30 m / x = tan(78º)
January 18, 2017

math
[1 - (5/8)] * [1 - (1/6)]
January 18, 2017

Geometry
the x-distance from p1 to p2 is ... 6 - -4 the y-distance from p1 to p2 is ... 9 - -7 divide the distances by 4 to find the "length" of each step start at p1 and add consecutive steps to find the 3 division points
January 18, 2017

algebra
biologists use a Punnett square to show the geneotypes if both parents are RL, the following outcomes are equally probable ... RR, RL, LR, LL
January 18, 2017

math
2.1 = a [1/2^(1000/24360)] log(2.1) = log(a) + (1000/24360)log(1/2) 2.1606 ?
January 18, 2017

MATH HELP
the other 4 committee members come from the group of 6 faculty and 2 students ... 8C4 number of ways is ... 6P2 * 8C4
January 18, 2017

Math
a 5x5 grid has 25 blocks each block is 1/25 or 4% how many blocks for 24%
January 18, 2017

Maths
45 L is 45000 cm^3 (45000 / 2) seconds
January 18, 2017

Pre-cal/trig
the rope reaches around the corner on the 18 ft side, but not on the 22 ft side so the area is half of a 42 ft dia circle, plus a quarter of a 6 ft dia circle
January 18, 2017

Math
L = 3 T L + 15 + T + 15 = 38 substituting ... 3T + 15 + T + 15 = 38 = 4 T + 30 solve for T, then substitute back to find L
January 18, 2017

Chemistry
commercial ice cream is agitated more vigorously to aerate the mixture and increase the volume you pay for air that the manufacturer gets for free the product should probably be sold by weight, not volume
January 17, 2017

Algebra
Jacinda appears to be running 10 minute miles ... 6 mph after 1 hr, Raj has gone 6 mi ... that's when Jacinda catches him
January 17, 2017

Physics
momentum is conserved 4500 * 17.5 = v * (4500 + 1350)
January 17, 2017

physics
energy = m g h 3.9E5 = 1.3E3 * g * h
January 17, 2017

physics
friction force = centripetal force ? m g = m v^2 / r ? = v^2 / (g r)
January 17, 2017

Physics
the dimensions are given to 3 sig fig ... that's what the answer should have 1 m^3 = (3.28 ft)^3 v = 43 * 18 * 15 * 3.28^3 ft^3 ... use 3 significant figures in the answer
January 17, 2017

serial dilutions
the mix is 1.5 diluent to .5 solution each dilution results in a solution that is 1/4 the concentration of the added solution ... .5 mL / (.5 mL + 1.5 mL)
January 17, 2017

Algebra 2
?n = n^(1/2) ?(8 x^3 y^5)
January 17, 2017

Algebra 2
(7x-2)^1/4 = 5 7x - 2 = 625
January 17, 2017

Math
horizontal (x) component ... magnitude * cosine vertical (y) component ... magnitude * sine
January 17, 2017

Algebra
try this (.08 * x) + [.07 * (x - 1400)] = 217
January 17, 2017

Physics
h = 1/2 g t^2 ... ?(2h/g) = t the time is directly related to the square root of the height
January 17, 2017

Physics
cable exerts an upward force gravity exerts a downward force find the net force a = f / m
January 17, 2017

Math
the difference is -7 the 5th term is 10 differences before the 15th term
January 16, 2017

physics
average velocity during penetration is ... (500 + 0) / 2 time = distance / velocity
January 16, 2017

science
impulse is the change in momentum over time
January 16, 2017

physics
the force of the Earth on the ball is the same as the ball on the Earth f = m a use the drop time to find the velocity v = a t
January 16, 2017

Math
horizontal means zero slope set f' equal to zero and solve for x
January 16, 2017

College Math - Quantitative Reasoning
.93^3 = .804357 1 - .804357 = .195643 rounds to 19.6%
January 16, 2017

College Math - Quantitative Reasoning
what do you think is the right answer? the problem statement is not correct your calculations are fine
January 16, 2017

Physics
(a) looks good part (b) may be a "trick" question velocity is a vector quantity, while speed is a scalar the answer might be zero
January 15, 2017

Chemistry
sounds like hydrogen peroxide
January 15, 2017

Math
your work looks okay C1 is 60 times C2 ... so V1 should be 1/60 of V2
January 15, 2017

Chemistry - Enthalpy
the tea (water) loses the energy gained by the spoon 250.0 * (90.00 - 85.00) * 4.184 4 sig fig ... not 5 as in your answer
January 14, 2017

Physics
1/2 * 68.6 * (4.92^2 - 1.12^2)
January 14, 2017

maths
the whole circle is 2? ... or 20?/10 3?/10 - 20?/10 = ?
January 13, 2017

math
2L + 2W = 52 L = W + 4 substituting ... 2(W + 4) + 2W = 52 4W + 8 = 52
January 13, 2017

algebra 2
7C3 * 5C3
January 12, 2017

algebra 2
16000 is 4000 above the average 4000/3200 = 1.2 sd use a z-score table to find the probability
January 12, 2017

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