Wednesday
February 10, 2016

Posts by scott

Total # Posts: 706

Chem
it looks red because it reflects the red wavelengths and absorbs the others
February 5, 2016

Physics
uniform acceleration means that the average speed is the numerical average of the initial speed and the final speed average speed ... (30 + 60) / 2 = 45 60 s in a min ... 60 min in an hr distance = 45 * 60 * 60 * 2 (meters)
February 5, 2016

chemistry
divide the total moles by the total L moles ... (.125 * .43) + (.017 * 1.8) Liters ... .125 + .017
February 5, 2016

math
24 * 3/8 = ?
February 3, 2016

Math
9.15 / 6.10 = 1.5
February 3, 2016

math
1 1/2 is six quarters 6 * 3 = ?
February 3, 2016

Chemistry
525 mL of .5 M solution contains (.525 * .5) moles of solute since you get 2 Cl-ions from each CaCl₂ you will need...(.525 * .5 * .5) moles of CaCl₂, dissolved in 525 mL of solution molar mass of CaCl₂ is 111 g (.5 * .5 * .525 * 111) g of CaCl₂
February 2, 2016

Math
6t + 1x + 3f = 35 + 10 = 45...(A) t + x + f = 13...(B) t = x...t - x = 0...(C) (A) - 3 (B)...3t - 2x = 6 subtracting 2(C)...t = 6 substitute back to find x and f
February 1, 2016

science
let [NO₂] equal 2x (2x)^2 = 0.0466 * (1.0 - x) 4 x^2 + 0.0466 x - 0.0466 = 0 you can use the quadratic formula to find x but answer 5 is the only one that makes sense
February 1, 2016

math
graph y = x^2 and y = x^3 (use fooplot_dot_com) the intersections are the solutions
February 1, 2016

physics
clarifying Rp = 12.5 * g Rq = 9.5 * g
February 1, 2016

physics
p and q are 4.0 m apart moments around q 4 p = (10 * 5) + (4 * 2) - (8 * 1) p = 12.5 Rp = 12.5 g moments around p 4 q = (8 * 5) * (4 * 2) - (10 * 1) q = 9.5 Rq = 9.5 g
February 1, 2016

math
there is no solution they have the same experience step value; but the starting salaries are different a Q teacher with equivalent experience will always have a $2000 higher salary than an R teacher
February 1, 2016

Math
step 6 x = y = 1 so division by x-y is division by zero a BIG no-no
February 1, 2016

math (grade6)
if Connor sold p fewer than Cassie then Cassie sold p more than Connor Connor sold 50 so Cassie sold 50+p
February 1, 2016

Physics
at one time constant (τ) the current is approx. 63% of max
January 31, 2016

science
not much info...
January 31, 2016

math
x² = 26² - 24² this is actually a Pythagorean triple...5-12-13 in this case...10-24-26
January 28, 2016

Math
4 x ≤ 17.50 - 4.50 4 x ≤ 13 x ≤ 3.25
January 28, 2016

Math- Algebra
8 n ≤ 60 dividing by 8... n ≤ 7.5
January 28, 2016

Math
14 gal and 25 mpg means you can drive 350 mi on a full tank...14 * 25 36 mi per day for 10 days is 360 mi so you have to gas up on the 10th day you can drive for 9 days before refueling
January 28, 2016

Math
8 * (30 + 4) = 240 + 32 = 272
January 28, 2016

math
9 char for the 1st position 9 for the 2nd 8 for the 3rd 7 for the 4th 26 for the 5th 9 * 9 * 8 * 7 * 26
January 28, 2016

General Chemistry
the partial pressures are the same ratio as the product moles from the reaction equation p CO₂ = 2/9 * 2.50 atm p N₂ = 1/3 * 2.50 atm p H₂O = 4/9 * 2.50 atm
January 28, 2016

Physics
the horizontal component of the stone's velocity is ...12 m/s * cos(30º) multiply by 8 s to find the distance
January 28, 2016

Physics
the speed is the vector sum of the plane and the wind north and east are perpendicular, so it's a right triangle s² = 499² + 87²
January 28, 2016

Science
looks like D
January 28, 2016

science
the normal force is...5 g cos(30º) the force along the ramp is ... 5 g sin(30º) 5 g sin(30º) = μ 5 g cos(30º) sin(30º) / cos(30º) = tan(30º) = μ
January 28, 2016

Science
good answer
January 28, 2016

Chemistry 101
one inch equals 2.54 cm a mL is the same as a cm³ the volume of the ball (in mL) is 4/3 * π * 1.26³ looks like a floater
January 28, 2016

Algebra
1/f = 1/o + 1/i 1/(1/4) = 1/(1/2) + 1/i 4 = 2 + 1/i i = 2
January 28, 2016

Chemistry 101
s.h. = 3450 / [10.65 * (99.9 - 28.5)]
January 28, 2016

Chemistry 101
mass = 1.2347 lb * 453.6 g/lb width = 1.256 ft * 30.48 cm/ft D = mass / [width * 12.6 * 45.6] the answer should be rounded to 3 significant figures
January 28, 2016

Wave
greater
January 27, 2016

science
the Sun appears to move across the sky because the Earth is rotating the Sun "moves" westward, so the Earth is rotating eastward
January 27, 2016

Math
bike...d = 6t ... d/6 = t bus... 26 - d = 30 (t - 1/3) substituting...26 - d = 30 (d/6 - 1/3) 26 - d = 5d - 10 36 = 6d
January 26, 2016

Physics
flying N at 250 km/h for 30 min should put him at 125 km N of the start the wind has pushed him 75 km N and 40 km W in 30 min so the wind is blowing 150 km/h N and 80 km/h W Vw² = 150² + 80² the tangent of the angle (west of north) is...8/15
January 26, 2016

Physics
the velocities add as vectors they are perpendicular to each other v² = 6² + 4²
January 26, 2016

Science
protons are positively charged so it would repel electrons are negatively charged so it would attract
January 26, 2016

Physics
the radius of the Earth is 6.37E3 km gravitational force is inversely proportional to the square of the distance 9.81 * (6.37E3)² = 6.44 * (6.37E3 + h)²
January 26, 2016

Coulomb's Law
the force is inversely proportional to the square of the distance (inverse-square relation) the new force is 4 times the original 1 / (1/2)² = 1 / (1/4) = 4
January 26, 2016

math
the change is $5 that is 25% (5/20) of the starting value
January 26, 2016

Math
losing time means running too slow when an hour has passed, the clock has only moved 45 min it is running at 3/4 speed (45/60) so when it shows an hour has passed, an hour and 20 min (4/3 hr) has actually passed the correct time is...10:20 AM
January 26, 2016

Physics
pressure is measured in Newtons per square meter or Pascals 20 m below the surface, there are 20 cubic meters of water stacked up 20,000 kg * 9.8 m/s² = 2.0 x 10⁵ N the water pressure is...2.0x10⁵ Pa the total pressure is...3.0x10⁵ Pa
January 26, 2016

Physics
t equals the fall time 0 = -4.9 t² + 1000 horizontal distance to target d = t * 200 km/hr convert km/hr to m/s the tangent of the angle is the height of the plane, divided by the horizontal distance to target
January 26, 2016

science
the kinetic energy of an object is equal to one half of the product of the object's mass and the square of its velocity KE = 1/2 m v²
January 26, 2016

physics
charge = capacitance * voltage coulombs = Farads * volts
January 26, 2016

Chemistry
each molecule of ammonium nitrate yields one ammonium ion and one nitrate ion so, twice the number of moles that you started with
January 26, 2016

Mathematics
draw the picture... d = h / tan(52º)
January 26, 2016

Science
a galvanometer measures current an electromagnet is the active element try B.
January 26, 2016

physics
see physics/tom about ten questions below this
January 26, 2016

physics
(a) v = 100 m / 8.70 s (b) constant acceleration (from zero) means that the average velocity during the acceleration phase is half of the final velocity (v/2) t + v (9.58 - t) = 100 m plug in v and solve for t (c) average acceleration is v/t
January 26, 2016

Science
the force (in Newtons) equals the product (multiply) of the charges (in Coulombs) divided by the distance (in meters) squared f = q₁ q2 / d²
January 26, 2016

math
this is true because a diameter is a straight line connecting two points on the circumference of a circle
January 25, 2016

Chemistry
the balanced equation reveals the answer C₃H₈ + 5 O₂ ---> 3 CO₂ + 4 H₂O looks like 6
January 25, 2016

phy 231
3.05 = -1/2 g t^2 + v sin(α) t + 2.10 19.2 = v cos(α) t plug in sin and cos values solve the system for v (and t)
January 24, 2016

Maths
5a + 10d + 7a + 21d = 167 10a + 45d = 235 solve the system for a and d S₂₀ = 20a + 190d
January 24, 2016

Physics
h = -1/2 g t^2 + 100 t + Ht 0 = (-4.9 * 25^2) + 2500 + Ht
January 24, 2016

science
to double the volume at a constant pressure, you have to double the ABSOLUTE (Kelvin) temperature 0ºC = 273.15ºK
January 24, 2016

statics
a score of 105 is one standard deviation above the mean the rule says that 68% of a normally distributed population lies within one standard deviation of the mean...half above the mean and half below so 34% are within one standard deviation above the mean this means that 16% ...
January 24, 2016

ALgebra
t for ten and w for twenty t + w = 54 10 t + 20 w = 780 solve the system
January 21, 2016

Science
you don't have any units ... and Mars is more than a light-second away
January 21, 2016

Physics
let's call right positive momentum is conserved (5 * 4) - (2 * 6) = (5 * .8) + (2 * v) 8 = 4 + 2v
January 21, 2016

physics101
how far from the end of the platform?
January 21, 2016

Chemisty
yes, it's A because the specific heat is lower, it takes less heat to raise the temperature a greater temperature change for a given amount of heat means that the temperature changes faster
January 21, 2016

physics
the desired acceleration is twice the gravitational acceleration, in an upward direction so the required force is 3 g's f = m a = 5 * 30 = 150 N
January 20, 2016

Chemistry
Cl is -1, so the Fe is +2 or +3
January 19, 2016

Physics
gravitational force parallel to the plane is...m * g * sin(30º) If the efficiency of the plane is 75%, then the coefficient of friction is .25 the normal force is...m * g * cos(30º) so the minimum force is [m * g * sin(30º)] + [m * g * cos(30º) * .25]
January 19, 2016

math
let t equal the fill time the pipes each fill a fraction of the pool the fractions sum to one (the whole pool) one fraction is t/8 the other is t/12 t/8 + t/12 = 1 24 is the LCD 3t + 2t = 24
January 19, 2016

Chemistry
it takes 4.179 J of heat to change the temperature of 1 g of water by one ºC 209 / (10.0 * 4.179) = temp. change looks like about a 5ºC increase
January 19, 2016

Chemistry
1 L of .1 M contains .1 moles volume = .1 mole / 12.1 mol/L .1 / .0121 mol/ml = ?
January 19, 2016

Chemistry 101
there are 2.54 cm in an inch a cm^3 is the same as a mL volume = π * .5^2 * 2.5 * 2.54^3 ...the result is in cm^3 multiply the volume by the density (.26)...that is the mass in g round the result to TWO sig fig ...that is the limiting number in the density value
January 19, 2016

Chemistry 101
there are 2.54 cm in an inch volume = π * 3.25^2 * 12 * 2.54 * 100 ...the result is in cm^3 ...it also equals the mass in g there are (approx) 453.6 g in a pound ...divide to find the mass in pounds
January 19, 2016

Chemistry 101
there are 2.54 cm in a inch ...12 inches in a foot ...5280 feet in a mile multiply to find the cm in a mile ...divide by 100 to find the meters convert 9.37 x 10^7 mi to meters ...by multiplying divide the result by 3 x 10^8 the answer is in sec ...THREE significant figures...
January 19, 2016

Math
there are 10 marbles, with 3 pink so the probability of pink is 3/10 for 2 pink draws (with replacement) ...probability = .3 * .3
January 19, 2016

math
3 differences (7 to 10) is 9 so d = 9 / 3 = 3 the 7th term is 6 differences from the 1st term ...1st + (3 * 6) = 7th ...1st + 18 = 19 so the 1st three terms are ...1, 4, 7
January 19, 2016

physics
momentum is conserved Mb * V1b = (Mb * V2b) + (Mp * Vp)
January 18, 2016

Physics
does your instructor teach significant figures?
January 18, 2016

physics
google electromagnetic spectrum energy
January 18, 2016

trigonometry
by Pythagoras 10^2 + x^2 = (20 + x)^2 x^2 + 100 = x^2 + 40x + 400 -300 = 40 x there appears to be something wrong with the numbers in the problem
January 18, 2016

math help please
did you check your 1st posting?
January 18, 2016

math help please
check your mail
January 18, 2016

Math ASAP
6. C 7. A distribute first then combine like terms
January 18, 2016

Pre-Calc
yes
January 18, 2016

Physics
the tangent of the elevation angle is the bullet drop (1.13 m) divided by the target distance (120 m)
January 18, 2016

Math ASAP
4. 2x = -2 7. correct
January 18, 2016

help on math
30% farther is 260 ft (200 * 1.30) up 25.5 and down 40.5 is a net down of 15 260 + 15 = ?
January 18, 2016

Math
double the first EQUATION , then subtract THE 2ND EQUATION to get y 2x + 4y - 2x - 3y = 22 - 50 y = -28 substitute into the 1st equation to find x
January 18, 2016

Algebra
90 + .7 m < 60 + .8 m 30 < .1 m 300 < m
January 18, 2016

High school mathmetics
using 10 sales (he may have more or less) [(500 * 4) + (600 * 6)] / 10 = 560
January 18, 2016

Pre Calc
the radius is √[3^2 + (-1)^2] = √10 sec(Θ) = √10 / 3
January 18, 2016

Math
one orbit in 3 hr 360º in 3 hr = 120º / hr 2º / min
January 18, 2016

Physics
an Ampere is a coulomb per second you're off by a factor of 60
January 18, 2016

math help
every 4 months is 3 times a year for 2 cars, 6 oil changes 6 * 4.5 = 27 qt of oil (27 / 5) * 14.99 = ? looks more like B but if the oil has to be purchased in 5 qt increments then 27/5 means 6 containers (answer C) but (again) there is oil left over that can be used next year ...
January 18, 2016

8th grade math and algebra class
y is usually graphed as a function of x bags on the x-axis total cost on the y-axis you should get a line with the slope changing at intervals you may need different scales on the two axes
January 18, 2016

Physics
m g = 2 * 1/2 k x^2 m g = k x^2 m g / x^2 = k
January 17, 2016

Physics
Vbullet = Vblock-bullet * (Mblock-bullet) / Mbullet 1/2 Mbb Vbb^2 = Mbb g * .658 * 6.66 Vbb = √(2 g * .658 * 6.66)
January 17, 2016

Math/ algebra
you found the answer...1/16 6.25%
January 17, 2016

Maths
just find the perfect squares on either side of the given root A) √4 , √9 --- 2, 3 B) √25 , √36 --- 5, 6 the rest work the same way
January 17, 2016

chem
Zn + 2 HCl ---> ZnCl₂ + H₂ so .1 moles of HCl reacts with .05 moles of Zn molar mass of Zn is 65.38 g .05 * 65.38 = ?
January 17, 2016

  1. Pages:
  2. 1
  3. 2
  4. 3
  5. 4
  6. 5
  7. 6
  8. 7
  9. 8
  10. Next>>