Saturday
February 25, 2017

Posts by Scott

Total # Posts: 1,829

Algerbra
the vertex is on the axis of symmetry ... x = -b / 2a f(x)=x^2+2x-3 ... x = -2 / 2*1 = -1 f(x)=x^2-3x+1 ... x = - -3 / 2*1 = 3/2 plug the x's into their functions to find the y's for the vertex coordinates
February 8, 2017

math
sin(0) = 0 ... sin(90) = 1 so ... sin(50) > sin(40) cos(0) = 1 ... cos(90) = 0
February 8, 2017

Chemistry
there are 1000 L in a cubic metre so the density is 3000 g/L the molar mass is 44.956 g so one L contains ... 3000 / 44.956 moles the number of unit cells is half the number of atoms the volume is ... 1 L / [(3000 / 44.956) * 6.02E23 / 2]
February 8, 2017

math
d = 3 q 10 d + 25 q = 385 solve the system using substitution or elimination
February 8, 2017

Further Mathematics
11th term is 10 cr from 1st term 7 * 3^10
February 8, 2017

Math
-5 = -a + b - c y' = 3a x^2 + 2b x + c ... 4 = 3a - 2b + c y" = 6a x + 2b ... 0 = -6a + 2b 3 equations, 3 unknowns ... solve the system
February 8, 2017

mATH
520 X [1 + (0.04/12)]^60 IS THIS RIGHT WAY TO DO THIS just clarifying
February 8, 2017

Physics
150 kN to pull 12 cars to pull one car ... 150/12 kN
February 8, 2017

physics
momentum is conserved (75 * 2) + (50 * v) = 0
February 8, 2017

Math
x * x * (x - 3) * (x + 1)
February 7, 2017

Chem
reacts with water to form sulfuric acid this is the "acid rain" reaction
February 7, 2017

Math
it's an even power regardless of the sign of x, f(x) will always be positive
February 7, 2017

Math
h + c = 160 ... 200 h + 200 c = 200 * 160 500 h + 200 c = 369 * 160 subtract equations to eliminate c solve for h, then substitute back to find c
February 7, 2017

Mathematics
the area of the bottom of the box is ... 3456 / 6 = 576 (x + 12) [(576 / x) + 12] = 1500 x is one dimension, 576/x is the other
February 6, 2017

Physics
800 N * 20 m = 16000 J per second means 16 kilowatts
February 6, 2017

Math
h(g(x)) = 9 - (x + 3)^2 ... = -x^2 - 6x the max is on the axis of symmetry ... x = -b / 2a = 6 / -2 = -3 plug in -3 to find the maximum
February 6, 2017

science
v = mass/density = 2.4 kg / 2.70 g/cm^3 2.4 is only 2 sig fig
February 6, 2017

Math
let x be the edge length of the corner squares the volume of the box is ... v = x (12 - 2x)^2 ... v = 144 x - 48 x^2 + 4 x^3 the 1st derivative will show the maxima/minima plug in the values to find the volume
February 6, 2017

Physics
the difference in densities gives you the "lift mass" per m^3 v = 800 kg / (1.25 kg/m^3 - 0.18 kg/m^3)
February 6, 2017

Physics
the metric unit of pressure is the Pascal (Pa) ... one Newton of force over one square meter a cubic meter of water has a mass of a thousand kg (a metric ton) ... it exerts a force of 9.81 kN stacked 100 high, the pressure at the bottom is ... 981 kPa
February 6, 2017

Algebra
the vertex is on the axis of symmetry x = -b / (2 a) = -6 / (2 * -1) = 3 plug 3 into the function to find the y-coordinate
February 6, 2017

physics
a straw works because when you lower the pressure on one end (by sucking), atmospheric pressure pushes the liquid from the other end the airtight cork prevents the atmospheric pressure from pushing on the liquid, so it won't go up the straw
February 6, 2017

physics
a cubic meter of water is a metric ton ... 1000 kg .4 m^3 / 24 m^2
February 6, 2017

Intermediate Algebra
c + h = 150 ... 325 c + 325 h = 325 * 150 325 c + 525 h = 445 * 150 subtract equations to eliminate c ... then substitute back to find h
February 5, 2017

Math
0 = x^2 - 2x + 15 x = [2 ± ?(4 - 60)] / 2 x = 1 ± i?14
February 5, 2017

physics
v is squared, doubling the uncertainty the value is then divided by y, which adds its uncertainty (2 * 3.34%) + 5.00%
February 5, 2017

physics
v is sq
February 5, 2017

physics
gas is correct
February 5, 2017

physics
the ke at the bottom equals the pe at the top both measured in Joules
February 5, 2017

physics
e = m g h = 7.2 * 9.8 * 1.2 (Joules)
February 5, 2017

math
worst case ... he takes out 5 ya and 7 gp the 13th fruit will fill the requirement
February 5, 2017

maths
find the average area of the top and bottom multiply by the height ... this is the volume in cm^3 divide by 1000 to find litres
February 5, 2017

Algebra
savings is dependent on weeks (98 - 65) / (6 - 3) = $11 / wk
February 5, 2017

Alg/Trig
0 = -16 t^2 + 112 t factoring ... 0 = -16 t (t - 7) 0 = -16 t ... t = 0 (launch) 0 = t - 7 ... t = 7 (return)
February 5, 2017

9th grade physical science
the density
February 5, 2017

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

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