Friday

July 31, 2015

July 31, 2015

Total # Posts: 21,579

**math**

3 x^2 - 12 x - 7 = 0 x = [12 +/- sqrt (144 + 84 ) } / 6 [ 12 +/- sqrt(228) ] /6 [ 12 +/- 2 sqrt(57) ]/6 2 +/- (1/3)sqrt(57)
*May 31, 2015*

**nuclear chemistry**

atomic number of Ir = # of protons = 77 so mass of protons = 77.56056 amu mass of neutrons = 110.9526 amu total mass = 188.51316 amu 188.51316 - 187.95883 = .55433 grams/mol = .00055433 kg/mol * c^2 for energy /mol .00055433 kg/mol * 9 * 10^16 = .00498897 *10^16 Joules/mol ...
*May 31, 2015*

**Math**

x = (8 - 3 y) then 3 (8 - 3 y) - 2 y = 2 24 - 9 y - 2 y = 2 11 y = 22 etc
*May 30, 2015*

**Math**

If you learned FOIL, use it otherwise use the distributive property 2 y(3y-2) -3 (3y-2) = 6 y^2 - 4 y - 9 y + 6 = 6 y^2 - 13 y + 6
*May 29, 2015*

**Math**

There are 16 kids and 16 beds total. We know that Tim is in green. So the question is what is the probability that Jorge will be in green. After Tim moves in, there are seven beds left in green out of fifteen beds total. so 7/15
*May 28, 2015*

**Algebra**

Associative http://www.mathwarehouse.com/dictionary/A-words/definition-of-associative-property.php
*May 28, 2015*

**Algebra**

graph the lines using = signs then look at corners It looks to me like x+y is max on y axis and is 4+3/2 = 5.5
*May 28, 2015*

**science**

Whoops, sorry. Watts. Thank you for catching that
*May 28, 2015*

**science**

work = force * distance in direction of force power = work per unit time so 900 * 40 /45 in Newton meters/second which is JOULES
*May 28, 2015*

**Algebra**

Use the distributive property of multiplication 3h (2h^2-7h+1) + 2 (2h^2-7h+1) then collect like terms
*May 28, 2015*

**Calculus**

[ 1 - (x/(1-x))] / [ 1 +(x/(1-x)) ] [ 1-x - x]/ [ 1-x +x] 1-2x if x = 1, g(x) is undefined
*May 27, 2015*

**Math**

stock amount = s bond amount = b gain = -.04 s + .032 b = -11.2 gain = -.032 s + .04 b = 3.2 =============================== https://oliveramesmacrof.wordpress.com/definition-of-financial-assets-money-stocks-bonds/
*May 26, 2015*

**Social Studies**

agree
*May 26, 2015*

**Physics**

mv^2/R = GmM/R^2 so M = v^2 R/G = 8.02^2 * 1037/ (6.674×10−11)
*May 26, 2015*

** Nah !!! Typo I bet**

The width is 3 times the length ? Strange table
*May 26, 2015*

**Physics**

It goes up a distance h in 2.9 seconds It goes horizontal a distance 12 meters in 2.9 seconds so u = 18 cos T = 12/2.9 cos T = .23 T = 76.7 degrees above horizontal so initial velocity up Vi = 18 sin 76.7 = 17.5 m/s h = Vi t -.5*9.81*t^2 h =17.5*2.9 - 4.9(2.9)^2 = 50.8-41.2 = ...
*May 26, 2015*

**Math**

x goes up, y goes down, d both x and y change that only happens in quads one and three I agree about 3
*May 26, 2015*

**math algebra 1**

L w = 82 d^2= (L^2+w^2) but L = d-2 and w = d-8 L^2 = d^2 -4 d + 4 w^2 = d^2 -16 d + 64 so L^2+w^2 = 2d^2-20d+68 = d^2 so d^2 - 20d + 68 = 0 d = [ 20 +/-sqrt(400-272)]2 d = 10 +/- 5.66 d must be bigger than 8 so d = 15.66 check my arithmetic
*May 26, 2015*

**Math Help**

she rolls one cube and gets some number. her chances of getting the same number again are 1/6 Her chances of getting a 5 on one spin are also 1/6 So six of one, half dozen of the other :)
*May 26, 2015*

**MATH**

(x-2)(x-2)
*May 26, 2015*

**physics**

Ke = (1/2) m v^2 = 500 joules m g h = 500 10 (9.81) h = 500
*May 25, 2015*

**Physics**

v^2/R = g v^2/45 = 9.81
*May 25, 2015*

**maths**

ACD = 90 - 35 = 55 so ABD = 55 (opposite same chord AD)
*May 25, 2015*

**physics**

call original speed v Original momentum = 2 v Final momentum = 2 v/4 + Mb Vb so 4 v = v + 2 Mb Vb or Mb Vb = 3 v original Ke = .5 (2) v^2 = v^2 final Ke = .5 (2)v^2/16 + .5 Mb Vb^2 so (15/16) v^2 = (1/2) Mb Vb^2 (15/8) v^2 = Mb Vb^2 = 3 v Vb (5/8)v = Vb but Mb Vb = 3 v so Vb...
*May 25, 2015*

**Algebra**

5/16 is greater than 4/16
*May 25, 2015*

**Algebra**

20.5/3.25 = 6.3 so only six with a little cloth left over
*May 25, 2015*

**American Government**

We have three branches in the US Executive (president etc) Legislative (congress) judicial (supreme and other courts) The press is sometimes referred to as the "fourth estate". However "the people" are part of governing so I would claim the the people is ...
*May 25, 2015*

**maths**

radius = 0.70 meters = r height = 1 meter = h vol = pi r^2 h area = 2 pi r^2 + 2 pi r h
*May 25, 2015*

**Math 7**

You are welcome.
*May 25, 2015*

**Math 7**

8*1.5 = 12 10*1.5 = 15 then 3*12 = 36 3*15 = 45
*May 25, 2015*

**medical science**

Sorry - I do physics.
*May 25, 2015*

**science**

yes, the mass per unit volume is greater than water for the penny and less than water for the ball.
*May 25, 2015*

**Math**

pi * 1.5 * 1.5 * 2 = 14.14 you did not square r in pi r^2
*May 25, 2015*

**Algebra (VERY IMPORTANT)**

If it is important, please identify what is numerator and what is denominator. eg 2/ [3(4x+2)^2] = 8 or 2/ { [3(4x+2)^2] +1 } = 9 or (2/3)(4x+2)^2 = 8 or whatever
*May 25, 2015*

**Algebra**

write them all properly in sci notation 3.21 * 10^1 4.2 * 10^5 1.1 * 10^9 Now it is pretty obvious that they are in order already
*May 25, 2015*

**Algebra**

yes
*May 25, 2015*

**Algebra**

Your turn
*May 25, 2015*

**Algebra**

4.74 * 10^-7 write the significant digits as a number from 1 to 9 and then just count left or right
*May 25, 2015*

**Algebra**

8.06 * 10^8
*May 25, 2015*

**science**

yes charge goes down mass goes down
*May 25, 2015*

**Chemistry actually**

14.0 what of KOH ? grams, milligrsms moles? How do you calculate what?
*May 24, 2015*

**Physics**

NO!!!! You assume that the acceleration, a, is CONSTANT. v = 0 + a t at t = 1.18 s v = 7.96 m/s so 7.96 = a (1.18) a = 7.96/1.18 NOW use x = 0 + 0 + (1/2) a t^2
*May 24, 2015*

**Physics**

x = 16 t also x = (1/2)(2) (t-5)^2 so 16 t = t^2 - 10 t + 25 t^2 - 26 t + 25 = 0 t = [ 26 +/- sqrt(676-100) ]/2 t = [ 26 +/- 24 ]/2 t = 2 or t = 25 t = 2 is negative x at start so use t = 25 which is 400 meters from start
*May 23, 2015*

**Science**

-2 e
*May 23, 2015*

**Algebra**

50*900 = 45000 50*20 = 1000 so 46,000 + 2 weeks = 48,000 a bit less because we used 920 instead of 919 so yes, pick 46,800
*May 23, 2015*

**Algebra**

You are welcome again.
*May 23, 2015*

**Algebra**

4 * 250 = 1000
*May 23, 2015*

**algebra--1 question**

[ (x+2)/{5(x-3)} ] (5)(2 x^2-5x-3) [ (x+2)/(x-3)] (2x+1)(x-3) (x+2)(2x+1)
*May 23, 2015*

**Algebra**

You are welcome.
*May 23, 2015*

**Algebra**

Yes
*May 23, 2015*

**Science**

I do not know. All you can say from this is that the volume of the object is the same as that of the water displaced. 30 N = 1000kg/m^3 * 9.81 m/s^2 * v v = 30/9810 cubic meters However we do not know how much force it exerted on the bottom of the container so we do not know ...
*May 23, 2015*

**Physics**

5 * 9.81 * 7 Joules
*May 23, 2015*

**advanced physics**

at the top of the loop, the force between the track and the wheels becomes zero when the centripetal acceleration is the same as g g = v^2/R = 9.81 m/s^2 so at the top v = sqrt(R g) now we need the speed at the bottom of the loop that will give us that speed at the top ...
*May 22, 2015*

**Algebra**

perimeter = twice width + twice length area = length * width = (3√7 + 3√5 )(2√7 - 2√5 ) = 6*7 + 0 - 6*5 = 12
*May 21, 2015*

**Math- simple polynomials**

Yes, what Ms. Sue said. When you divide n pennies up evenly between n cups, you have ONE per cup.
*May 21, 2015*

**Calc 1**

I suspect you mean ∫ dt/(1-7t)^7, u=1-7t so if u = 1-7t then du = -7 dt or dt = -du/7 so we have ∫( -du/7)/u^7 or -(1/7) ∫ u^-7 du -(1/7)(-1/6) u^-6 (1/42) u^-6 + C 1/[42(1-7t)^6] + C
*May 21, 2015*

**algebra**

60/1 = 60 miles/hour 300/5 = 60 miles/hour sure looks like 60 miles/hour
*May 21, 2015*

**physics**

g is about 9.81 m/s^2 down F = m a here F = -9.81 m so m a = -9.81 m a = -9.81 m/s^2 or g downward v = speed up v = Vi - a t = 10 - 9.81 t so v decreases proportional to time until it reaches 0 at the top of its flight. Then it starts down. that time is t = 10/9.81 h = height...
*May 21, 2015*

**physics**

same current, add voltages
*May 21, 2015*

**math**

Ava 100 Brittany 75 Ava 100 - (9/20)100 = 100 - 45 = 55 Brittany 75+55 = 130 Ava = 55 + (1/4)130 = 55+32.5 = 67.5 Britanny = 130 -32.5 = 97.5 97.5 - 67.5 = 30 more
*May 21, 2015*

**Maths**

walked for t hours times are t and 3.75-t 4 t + 12(3.75-t) = 25 -8 t = 25 - 45 = -20 t = 5/2 d = 4 (5/2) = 10 km
*May 21, 2015*

**maths**

so how many more pieces than cuts? 72 - 53 = 19 bu you have one more piece than cuts so 18
*May 21, 2015*

**Trig**

13^2 = 169 5^2 = 25 169-25 = 144 12^2 = 144 so: cos T = -5/13 sin T = +12/13 T/2 will be in first quadrant sin(T/2) = [(1-cos T)/2]^.5 = [ (1+5/13)/2]^.5 = [9/13]^.5 yes 3. =
*May 20, 2015*

**science**

8. If a farmer plants the same crop in a field year after year, the soil becomes less fertile. What causes this decrease in fertility? (1 point) A.erosion B.lack of water C.loss of topsoil*** D.loss of nutrients I THINK D --- LOSS OF NUTRIENTS. C ALSO CAN HAPPEN...
*May 20, 2015*

**statistic**

Well, that was fun :)
*May 20, 2015*

**statistic**

p boy = .5 p not boy = 1-p boy = .5 sure looks like a binomial experiment to me lets find the probability of four boys out of ten births for example P(10,4) = C(10,4) .5^4 * (1-.5)^6 = 10!/[4!(6!)] *(1/16)*(1/64) = 210 / 1024 = .205
*May 20, 2015*

**algebra**

t = k/s 12 = k/60 k = 12*60 t = (12*60) / 85 or t = 8.47 hours
*May 20, 2015*

**Math**

0.035 * 3026 * 1.5
*May 19, 2015*

**mathematics**

http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html might work better
*May 19, 2015*

**mathematics**

https://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html
*May 19, 2015*

**Math Please help!!!**

sure. It says he burns 420 calories every hour so in 1 hour, 420 in 2 hours , 840 etc The rest is just babble intended to confuse the enemy (student)
*May 19, 2015*

**Math Please help!!!**

420 t
*May 19, 2015*

**physics**

Of course that is just across the clock circuit, not including the battery itself. If you do a complete loop around any circuit the total potential changes add up to zero. That is fundamental to the meaning of potential of any sort, voltage, gravitational, elevation etc. In ...
*May 19, 2015*

**physics**

Mine too :)
*May 19, 2015*

**liberal arts math**

1080/4500 = x/100 = 1080/45
*May 19, 2015*

**physics**

500 * 20 / 50 in Joules
*May 19, 2015*

**physics**

75 * 9.81 * 1.75 Joules
*May 19, 2015*

**Phyics**

It is photons emmitted as electron drop from one discrete orbit to a lower energy orbit.
*May 19, 2015*

**math**

22+3 = 25 If there are several values of x with the same y, then if you turn it sideways there are many values of y for the same x and we can not write y = f(x) and get a unique answer. An example is a sine function y = sin x that is a perfectly good function, one y for each x...
*May 18, 2015*

**Chemistry**

mols of H2O produced = 5.671 /18 = .315 mols of CO2 produced = 36.933 /44 =.8394 Cx Hy Oz + n O2 ----> .8394 CO2 + .315 H2O well, y = .630 right off and x = .8394 z + 2 n = 2(.8394) + .315 = 1.99 but mass of O2 on left = 5.671+36.933-17.422 = 25.182 grams which is 25.182/32...
*May 1, 2015*

**Chemistry**

You have 5 O2 molecules for every 2 acetylene molecules P V = n R T where n (mols)is proportional to the number of molecules so for O2 125 (6) = 5 k R T for O2 P(3) = 2 k R T for C2H2 k R T are the same for both so 125(6/5) = P(3/2)
*May 1, 2015*

**algebra--1 question**

sqrt(w^2 + 25 w^2) = w sqrt (26)
*May 1, 2015*

**Chemistry**

P V = n R T At STP 1 mol is 22.4 liters so 3 liters =.134 mol of H2 There are 2 mols of Al for every 3 mol of H2 so mol Al = (2/3)(.134) = .0893 mol Al which is .0893 * 27 grams
*May 1, 2015*

**Differential Calculus**

v = Vi - 9.81 t 0 = Vi - 9.81 t at top Vi = 9.81 t = 19.62 meters/second Maybe get H as well falls for five seconds now h = Hi + Vi T - (1/2) g T^2 0 = Hi + 5 Vi - 4.9(25) Hi = 122.5 - 96 = 26.5 meters
*April 28, 2015*

**math**

11 s^2 = 1331 s^2 = 121 s = 11 the thing is a cube surface area = s^2
*April 28, 2015*

**math**

8.5 * 11 - 16
*April 28, 2015*

**phyiscs**

LOL !!! Your refrigerator has coils on the back that heat the room. 1. Motor compresses gas. Its pressure goes up but it gets HOT. 2. That hot pressurized gas goes through coils outside and behind the machine discharging the heat to the room and warming it up. 3. THEN the gas ...
*April 25, 2015*

**Math 222**

You can NOT factor that polynomial. You must either complete the square or equivalently use the quadratic equation you used the quadratic equation which is x = [ -b+/-sqrt(discriminant) ]/2a the discriminant is b^2 - 4 ac which is 9 + 20 = 29
*April 24, 2015*

**Science help**

I know nothing about magma but would pick liquid for minimal noise Do not need intensity as far as I know, triangulate using arrival times of waves.
*April 24, 2015*

**Science help**

microwave is RADIATION spoon is soup is conduction pasta moving is convection light waves is radiation
*April 24, 2015*

**Calc 1**

a when x = 9, function is vertical y--->oo when x is large negative or positive then y = 1 TRY NUMBERS! b dy/dx = [2x(x-9)^2 - x^2(2)]/(x-9)^4 = [2x^3 -38x^2 + 162 x]/(x-9)^2 the bottom is always + so the top is the whole thing if + then slope up, if - then slope down turns...
*April 24, 2015*

**physics 111 ????**

I scrolled all the way to the bottom and did not see any work by you so do not know where you got stuck. Surely you do not want to see if I can do them. I have been doing these since 1955.
*April 24, 2015*

**AP Physics**

Boats do not have backs. They have sterns or transoms. They also have bows. Anyway: Find original center of mass from the pier (not a dock but that term is actually often used these days for a pier). I will assume that the center of mass of the boat is 1.5 meters from the pier...
*April 24, 2015*

**Math**

Z score
*April 24, 2015*

**nope**

Described where?
*April 24, 2015*

**Math**

You are welcome.
*April 24, 2015*

**Math**

A B http://www.mathsisfun.com/data/standard-deviation.html
*April 24, 2015*

**physics 133**

1 Which of the following is the correct unit of k in the equation of a damped harmonic oscillator given as , where b is the damping factor and all the symbols have their usual meaning? ============================== F = - k x Newtons = -k * meters k is therefore in Newtons/...
*April 24, 2015*

**Math 222**

8). The polynomial for which you wish to find zeros is a^2 - 6 a + 9 = 0 Then I factored (a-3)(a-3) = 0 a = 3 or a = 3, in other words the vertex is on the x axis ============================= You could have completed the square (but it is already completed): a^2 - 6 a = -9 a^...
*April 24, 2015*

**Math**

LOL - if it came out 2/3, it is certainly not theoretical !
*April 24, 2015*