Wednesday
December 7, 2016

Posts by Scott

Total # Posts: 1,561

Algebra
m = 37 h - 1500
June 25, 2016

Physics
one charge is attracting and the other is repelling the 3rd charge must be farther from the larger charge and not between the two charges remember inverse square law 7.25 / (d + 20)² = 2.00 / d² 7.25 d² = 2 d² + 80 d + 800 5.25 d² - 80 d - 800 = 0 use ...
June 24, 2016

Chemistry
the molar mass of NaCl is ... 58.44 g the molar mass of KI is ... 166.00 g
June 24, 2016

Probability
it's a binomial expansion (r + t)¹⁰ ... you want the 8th term 10C7 [(40/75)³ (35/75)⁷]
June 24, 2016

Science
wavelength = velocity / frequency λ = 3.0E10 cm/s / 6.0E18 hz
June 24, 2016

Physics
the s.a. of a sphere is ... 4 π r² or ... π d² km² = 1E6 m²
June 23, 2016

math
6497 , 5579 , 5993
June 23, 2016

Math
1.11 x = 5173
June 23, 2016

Physics
(a) f = m a = .02/32 * 1E5 = 63 lb (b) yes ... Newton's 3rd Law ... equal and opposite reaction (c) .007 s * 1E5 ft/s² = 700 ft/s sounds like an air rifle
June 22, 2016

Physics
the longest wavelength (lowest energy) would be from the 2nd excited state to the 3rd excited state
June 22, 2016

Physics
the plane must fly northeasterly so that its north velocity component equals the south velocity component of the wind 250 sin(Θ) = 50 sin(45º)
June 22, 2016

Math
the height of the satellite and the line through the stations form the right angle of a right triangle there are two hypotenuses (hypoteni?), one from each of the stations to the satellite curious as to how you found A) without the height h / a = tan(87º) h / (a + 35) = ...
June 22, 2016

Physics
v² / r = g sin(2Θ) / 2
June 22, 2016

Physics
u - u/20 = 19u/20 = .95u .95² = .9025 the bullet loses about 10% of its energy (kinetic), as work passing through the plank it should stop in the 11th plank
June 22, 2016

Algebra
salary = 1800 + (sales * .042) 4824 = 1800 + .042 s 3024 = .042 s
June 21, 2016

Physical Science
(6.38E6)² / .89 = (6.38E6 + h)²
June 21, 2016

Physical Science
h = ½ g t² ... .3 = ½ * 9.8 * t² t = √(.6 / 9.8) distance = 3.1 * t
June 21, 2016

Mathematics
almost ... 12/4 = 3 ... not 8 (not an exponent)
June 21, 2016

statistics
this is a binary expansion (h + t)⁴ the term you want is...6 h² t² 6 * (2/3)² * (1/3)² = 24/81 = 8/27
June 21, 2016

Physical Science
F = G * (m₁ m₂) / r² F = 6.7E-11 * 4.8E24 / (6.4E6)² N
June 21, 2016

Math1(Please Help Me)
A.) about 99% of a normally distributed population lies within 2½ standard deviations of the mean 159 cm ± (2½ * 5 cm) 65.9 kg ± (2½ * 12.7 kg) B.) the weight seems more variable because the s.d. is a larger fraction of the mean C.) 7 cm ...
June 21, 2016

physics
d = r * t (80 * t/2) + (40 * t/2) = 60 120 t = 120 ... t = 1 r = d / t = 60 km / 1 hr = 60 km/hr
June 21, 2016

Math1
A.) the data is clustered around a central value (mean), with fewer data points towards the edges B.) from statistical software ... mean = 195.5 , s.d. = 18.33 231 lbs is 1.94 s.d. above the mean [(231 - 195.5) / 18.33] this represents 2.6% of the population .026 * 218 = 5.67...
June 20, 2016

Math
2x² + 5x - 52 = 0 (2x + 13) (x - 4) = 0 x = 4
June 20, 2016

Chemistry
you need 7 moles of HCl for a complete reaction 7 moles / .85 M/L =
June 20, 2016

algebra
x = 5 is correct
June 20, 2016

Math (pre-celc 12)
you are correct
June 20, 2016

Please Help Me!
A.) the data is clustered around a central value (mean), with fewer data points towards the edges B.) from statistical software ... mean = 195.5 , s.d. = 18.33 231 lbs is 1.94 s.d. above the mean [(231 - 195.5) / 18.33] this represents 2.6% of the population .026 * 218 = 5.67...
June 20, 2016

math
3.54E7 m / 3.00E8 m/s = 1.18E-1 s
June 20, 2016

Math
60º is 1/6 of the circle a = [π (7/2)²] / 6
June 20, 2016

math
angle?
June 20, 2016

math
answered
June 20, 2016

math
the area of an isosceles right triangle is one half the square of the hypotenuse a = 3² / 2
June 20, 2016

Math
w = 250 m / tan(50º)
June 19, 2016

Maths
adding 6 ... 2 < 2x < 18 dividing by 2 ... 1 < x < 9 integers greater than 1 and less than 9
June 19, 2016

Physical Science 8th Grade
1. in a surface wave (like water); the water goes up and down, but the wave travels across (parallel to) the surface 2. energy is transferred 3. sound 4. c 5. parallel to (sound)
June 19, 2016

Maths
w = 250 m / tan(50º)
June 19, 2016

Physics
power is power...mechanical or electric...measured in Watts watt = Joule/s = volts * amps watt·sec = Joule kilowatt·hr = 3.6 MJ energy = energy
June 19, 2016

math
(59 - 3) / 4 = 14 14 + 1 = 15 terms
June 19, 2016

Math
z1 = 50 kg c2 = 150 kg t1 = 4/3 t2 4/3 t2 + t2 = 140 kg ... 7/3 t2 = 140 ... t2 = 60 kg ... t1 = 80 kg c1 = 200 kg - 50 kg - 80 kg = 70 kg c1 + c2 = 220 kg
June 19, 2016

Math
implicit differentiation 2 x dx/dt - 2 y dy/dt = 0 substituting [2*(-3)*(-4)] - [2*2*(dy/dt)] = 0
June 18, 2016

Physics
13 = -½ g t² + 24 t + 2 solve for t...there will be two solutions (up and down) the velocity is...v = 24 - g t ...use the up (smaller) time
June 18, 2016

physic mechanic
momentum is conserved .15 * 3.8 = 4.75 * v
June 18, 2016

physical science
momentum is conserved .16 * 25 = (85 + .16) * v
June 17, 2016

Science : Physics
balanced means zero net force Newton's 2nd law ... f = m * a if the force equals zero, then the acceleration also equals zero
June 17, 2016

Geometry
1 + 2 + 3 is a straight angle (180º) 3 is a right angle (90º) 1 + 2 = 90 = x + x - 6 = 2 x - 6
June 17, 2016

Science : Physics
the work done in stopping is... f * d ... 60 * 26.3 = ? J the work equals the initial kinetic energy of the object... ½ m v² 60 * 26.3 = ½ * 15 * v² v = √(8 * 26.3) m/s be aware of significant figures...
June 17, 2016

Math
1 + 2 + 3 is a straight angle (180º) 3 is a right angle (90º) 1 + 2 = 90 = x + x - 6 = 2 x - 6
June 17, 2016

MATHS
(120 / 2) √2 + 150
June 17, 2016

math
a) use fooplot dot com b) 4 ft c) set h=0 , then solve for t d) set h=30 , then solve for t ... two solutions e) never f) axis of sym ... 50 / (2 * 16) g) use value from f) in h(t)
June 16, 2016

Please Help
the smallest value for (X-5)² is zero so the range is any real number greater than or equal to 7
June 15, 2016

Algebra
they close the distance at 32 mph (128/4) x + x/3 = 4x / 3 = 32 mph
June 15, 2016

Math
they are separating at the rate of 125 mph s + s + 15 = 125 ... 2 s = 110
June 15, 2016

college algebra
no male non-smokers 17 smokers ... 5 female, 12 male 13 non-smokers, all female
June 15, 2016

math
3³ + 3 - (3/3)
June 15, 2016

Physics
his energy (gravitational) is ... m g (h+d) = 45 * 9.8 * (7+d) the depth (d) he reaches is based on the work done by the water ... w = f d = 1500 d 1500 d = 45 * 9.8 * (7+d) f = m a ... a = f / m his deceleration is the net force (gravity minus water) divided by his mass a...
June 15, 2016

science
two quarts is four pints (4 * 30%) + (3 * 20%) = (4 + 3) * x
June 15, 2016

science
her mass is the same -- 24 kg her weight is 1/6 of her weight on earth
June 15, 2016

maths
a) v = ⅓ π r² h = 16 π b) the radius of the circle is 5 cm ... √[(8/2)² + 3²] = 5 Θ = 2 π * 8 / 10
June 15, 2016

Maths
the ladder, wall, and ground form a Pythagorean triple (like 3-4-5) this one is 5-12-13
June 13, 2016

Physics
F = charge * velocity * field strength F = 2.76E-13 N
June 13, 2016

Physics
the normal force is equal to the gravitational force ... m g
June 13, 2016

Maths
12 pens out of 40 are neither red nor green a randomly selected pen has a 12/40 or .3 probability of being in this group not sure where 3/4 comes from...
June 13, 2016

Algebra
a negative number, multiplied an odd number of times, is still negative no real number, multiplied an even number of times, can be still negative pos times pos is pos neg times neg is pos
June 13, 2016

Physics I (Classical)
for b) and c), determine the force (Q) using the acceleration components and the components of (P) ... you have the mass of the block f = m a ... by components
June 13, 2016

Engineering science
distance up equals distance down time up equals time down 3.5 s to peak g = 9.8 m/s² average velocity = (3.5 * 9.8) / 2 total distance = (ave vel) * 7
June 12, 2016

Chemistry
12.5 mM HCl and 7.5 mM KOH after netralization ... 5.0 mM HCl in 75.0 mL of solution ... .067 M HCl pH = -log[H⁺] = -log[.067]
June 12, 2016

Math
the amount of flour needed is directly proportional to the number of cakes...more cakes, more flour the constant of proportionality (k) is the flour per cake 4⅗ * k = 2/3 dividing both sides by 4⅔ k = 10/69 lb/cake seems more like a cupcake...
June 12, 2016

Science
yes
June 11, 2016

Physics
work is ... force times distance you have both ... 125 N , 45 m
June 11, 2016

Calculus
a b = 2 ... a = 2 / b s = a + b = 2/b + b ds = db (-2/b² + 1) ds/db = -2/b² + 1 = 0 b = √2 s = 2√2
June 10, 2016

Physics
your analysis looks okay your problem might be too many significant figures in your result
June 9, 2016

Biostatics
15.9% of the fish have lengths more than 1 standard deviation below the mean
June 8, 2016

Math
diagram?
June 8, 2016

Physics
the force constants add in parallel 16 N/m
June 8, 2016

Physics
1)as the elevator accelerates upward, the student's weight increases f = m a ... w = m a = m (g + e) 2)the elevator decellerates to a stop, so the student's weight is less than normal...same equations as #1 3)the greater the CHANGE in weight, the greater the ...
June 7, 2016

Physics
constant force means constant acceleration the graph is a flat line (zero slope)
June 7, 2016

Algebra
f(x) = 4 x - x²
June 7, 2016

mat
3 n + 4 = 15 / n 3 n² + 4 n - 15 = 0 (3 n - 5) (n + 3) = 0 n = 5/3 ... or ... n = -3
June 7, 2016

Science
1000 mL * .25 M = x mL * .75 M
June 7, 2016

Science
sulfuric is a binary acid [.56 / (2 * .25)] * .030 M
June 7, 2016

Physics
GPE = m * g * h = .6 * 9.81 * .3 J KE = GPE v = √(2 g h) m/s
June 7, 2016

Chemistry
D.
June 7, 2016

Science ~ Astronomy
not a ... we don't have the technology yet ... same for c b) ... computer modeling
June 6, 2016

Statistics
m - m ... 1/3 * 1/3 = 1/9 m - f ... 1/3 * 2/3 = 2/9 f - m ... 2/3 * 1/3 = 2/9 f - f ... 2/3 * 2/3 = 4/9 (i) 1/9 + 4/9 = 5/9 (ii) 2/9 + 2/9 = 4/9
June 6, 2016

physics
30 m/s / 1.5 m/s²
June 6, 2016

science
divide the mass of the zinc by its molar mass (65.4 g) to find the number of moles each mole of zinc will produce a mole of hydrogen gas (diatomic) multiply the moles by the molar mass of H₂ (2.02 g)
June 5, 2016

chemistry
44 g is one mole of propane so four moles of water are produced the molar mass of water is 18 g
June 5, 2016

math,algebra
L + C = 150 ... 75 L + 75 C = 150 * 75 40 L + 75 C = 7400 subtract the equations to eliminate C and solve for L
June 5, 2016

Science
find its mass (weigh it) then do like Archimedes and submerge the object to find its volume divide the mass by the volume
June 5, 2016

MATH
the radius, distance, and half the chord form a 5-12-13 triangle
June 5, 2016

MATH
the radius, half the chord, and the distance form a 3-4-5 triangle
June 5, 2016

chemistry
the sodium is the limiting reactant .6 moles
June 5, 2016

Math
[(76 - x) / 4]² + (x / 4)² = 205 76² - 152 x + x² + x² = 205 * 16 use the quadratic formula to find x either x or 76-x is shorter
June 5, 2016

math
s² < 6 s ... s < 6 any square with a side length less than 6
June 5, 2016

Chemistry
the estimated mass is to high (positive error) the amount is 10/240 ... A
June 5, 2016

chemistry
close ... D the decimal point makes the trailing zero significant
June 5, 2016

Math
when you connect the midpoints, the triangle formed is half the perimeter of the original triangle
June 4, 2016

gen chem
looking at the formula, there are two hydrogens for every carbon so ... 4.06x10^21 atoms of hydrogen there are 6 carbon atoms in each glucose molecule, so the number of molecules is ... 2.03x10^21 / 6
June 4, 2016

Math - Year 10 - Simult. Equations
o + t = 21 1 o + 2 t = 30 subtracting equations t = 9
June 3, 2016

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