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Posts by Scott

Total # Posts: 2,123

Math
x^2 + y^2 = r^2 9 + 4 = 13 sin = y / r = -2 / √13 = -2√13 / 13

Math
sin^2 + cos^2 = 1 sin^2 + 2/9 = 1 sin^2 = 7/9 sin = ±√7 / 3

Cal
oops...got my axes swapped thanks, Cal

Cal
the shell method seems best the corners of the cross section are (4,0), (5,0), (5,.04), (4,.0625) not needed for solution, but helps to visualize the radius of the shell is x+2 volume = 2π * r * L * thickness = 2π * (x + 2) * (1 / x^2) * dx integration limits are 4 ...

Math
63/16 = tan(Θ) nearest degree (not tenths)

maths
better, but "motion"? measures of central tendency are: mean (average), median, and mode

maths
something is amiss in the question (besides spelling) if x is greater than 95 x+2 cannot be less than 72

Math
45º reference angle in quad II looks like A

Math
2π is a full circle...so they end at the same place π/6 + 2π = 13π/6 π/6 - 2π = -11π/6

PHYSIC 220
(a)i = [19.6 * cos(153º - 90º)] - [16.7 * cos(136º - 90º)] j = [19.6 * sin(153º - 90º)] - [16.7 * sin(136º - 90º)] k = 2.40 - 0 (b) d = √(i^2 + j^2 + k^2)

Geometry
(100% + 25%) / 100% = 5/4

Physics
watts = volts * amps = amps^2 * Ω 600 W = 6 V * 100 A = 100^2 * Ω A)energy = 1/2 * farads * (volts)^2 B)use C and R (Ω) to find the time constant of the circuit the capacitor is 95% discharged after 3 time constants

algebra
Use the rational zeros theorem to find all the real zeros of the polynomial function. Use the zeros to factor f over the real numbers. f(x)= x^4+6x^3-11x^2-24x+28 Molon

Chem
it looks red because it reflects the red wavelengths and absorbs the others

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)

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

math
24 * 3/8 = ?

Math
9.15 / 6.10 = 1.5

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

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

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

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

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

physics
clarifying Rp = 12.5 * g Rq = 9.5 * g

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

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

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

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

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

science
not much info...

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

Math
4 x ≤ 17.50 - 4.50 4 x ≤ 13 x ≤ 3.25

Math- Algebra
8 n ≤ 60 dividing by 8... n ≤ 7.5

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

Math
8 * (30 + 4) = 240 + 32 = 272

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

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

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

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

Science
looks like D

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

Science
good answer

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

Algebra
1/f = 1/o + 1/i 1/(1/4) = 1/(1/2) + 1/i 4 = 2 + 1/i i = 2

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

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

Wave
greater

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

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

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

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

Science
protons are positively charged so it would repel electrons are negatively charged so it would attract

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

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

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

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

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

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

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

physics
charge = capacitance * voltage coulombs = Farads * volts

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

Mathematics
draw the picture... d = h / tan(52º)

Science
a galvanometer measures current an electromagnet is the active element try B.

physics
see physics/tom about ten questions below this

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

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

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

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

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)

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

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

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

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% ...

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

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

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

physics101
how far from the end of the platform?

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

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

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

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]

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

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

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

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

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

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...

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

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

physics
momentum is conserved Mb * V1b = (Mb * V2b) + (Mp * Vp)

Physics
does your instructor teach significant figures?

physics
google electromagnetic spectrum energy

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

math help please
did you check your 1st posting?

math help please
check your mail

Math ASAP
6. C 7. A distribute first then combine like terms

Pre-Calc
yes

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

Math ASAP
4. 2x = -2 7. correct

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 = ?

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