Sunday

July 5, 2015

July 5, 2015

Total # Posts: 21,427

**Physics**

The tension and mass density determine the speed of the wave along the string. The input frequency is the wave frequency wavelength = speed * period = speed/frequency so frequency, tension and mass density right
*June 4, 2015*

**Physics**

A yes B yes C No D yes I agree.
*June 4, 2015*

**Algebra**

L^2 + w^2 = d^2 (d-3)^2 + (d-8)^2 = d^2 d^2 - 6 d + 9 + d^2 -16 d + 64 = d^2 d^2 - 22 d + 73 = 0 d = [ 22 +/- sqrt(484 - 292) ] / 2 d = [ 22 +/- 13.9 ] / 2 d = 17.9 or 8.1 8.1 is impossible if the area is 84 so d = 17.9 ------------------- check then w = about 10 and L = about...
*June 4, 2015*

**Math**

66 = 2*33 = 2 * 3 * 11 99 = 3 * 33 = 3 * 3 * 11 20 = 2*10 = 2 * 2 * 5 etc, boring
*June 4, 2015*

**Math**

look at b^2 - 4 a c if +, then two intercepts if 0, then just grazes the x axis, one intercept if -, then never hits the axis, imaginary roots only if a x^2 + b x + c = 0 then - (a x^2 + b x + c) = 0 is the same because +0 = -0
*June 4, 2015*

**math**

sin^4x-cos^4x = (sin^2 x+cos^2 x)(sin^2 x -cos^2 x = 1 (sin^2 x - cos^2 x) = 2 sin^2 x - 1
*June 4, 2015*

**physics**

d1 = (1/2)(5)(64) Vi = 0 + 5 * 8 d2 = Vi * (12-8) d = d1 + d2
*June 4, 2015*

**math**

one leg of right triangle is 150 other leg is 120 sqrt (150^2+120^2) = 192
*June 3, 2015*

**Social Studies**

You are welcome.
*June 3, 2015*

**Social Studies**

Write your thoughts and perhaps a teacher will help. hints - where is the Statue of Liberty ? What words are on it? How many buffalo are around, not to mention native tribes ? Wicked difficult growing cotton and rice and stuff under the snow.
*June 3, 2015*

**Math**

slope = (13-10)/(5-4) for example = 3 so T = = 3 S + b 1 = 3 + b b = -2 so T = 3 S - 2
*June 3, 2015*

**Math**

sorry - I used 15 mph instead of 18
*June 3, 2015*

**Math**

at 12 it tskes t so d = 12 t at 15 it will take .25 leas time d = 15 (t-.25) so 12 t = 15 t - 15/4 3 t = 15/4 t = 5/4 d = 12(5/4) = 15 miles
*June 3, 2015*

**Math**

120 = x t so t = 120/x 120 = (x+5)(t-1/3) or 120 = (x+5)(120/x - 1/3) 120 (3)(x) = (x+5)(360 - x) 360 x = 360 x -x^2 + 1800 -5 x x^2 + 5 x - 1800 = 0 (x-40)(x+45) = 0 x = 40
*June 3, 2015*

**Math**

t is time after 12 noon f for freight train distance f = df = 50 t p for passenger train dp = 60 (t-1) when is dp - df = 300 ? 60(t-1) - 50 t = 380 10 t - 60 = 380 10 t = 440 t = 44 hours so one day and 20 hours so 8 am --------------------------------- total distance = 2d ...
*June 3, 2015*

**physics**

120/360 = 1/3 of circumference so distance pushed = d = (1/3) 2 pi (.9) work = force * d = 11 *d Joules power = work/time = 11 * d / 2.2 in Watts
*June 3, 2015*

**PHYSICS**

v = a t where a = alpha = angular acceleration = torque/I here I is moment of inertia of uniform disc = (1/2) m r^2 so I = (1/2)(6)(.04) = .12 and a = 30/.12 = 250 radians/s^2 then v = 250 t and theta = (1/2)a t^2 = 4 pi radians so 125 t^2 = 4 pi t = .317 second then v = 250(....
*June 3, 2015*

**math**

3 x^2 - 12 x - 7 = 0 x = [ 12 +/- sqrt(144+84) ] / 6 = [ 12 +/- sqrt(228) ] / 6 = [ 12 +/- 2 sqrt(57) / 6 = [ 6 +/- sqrt(57) ] / 3 Use PARENTHESES !!!~!!~!!!!! I can not tell whsat is your numerator.
*June 3, 2015*

**civics**

Looks pretty federal to me.
*June 3, 2015*

**civics**

yes
*June 3, 2015*

**civics**

Well which do you think based on the answer to your other question?
*June 3, 2015*

**math**

0 = 1^2 - 1 3 = 2^2 - 1 8 = 3^2 - 1 15= 4^2 - 1 25= 5^2 - 1 Term = n^2 - 1
*June 3, 2015*

**Physics**

As far as I know a right hand rule is a right hand rule.
*June 3, 2015*

**physics**

first get acceleration of the two masses a = F/m = (2*9.81)/(7) then: mg - T = m a 2*9.81 - T = 2 a T = 2 (9.81 - a)
*June 3, 2015*

**Math**

because if they were similar then if V to W is 5 and R to S is 10 then if similar W to X must be HALF of S to T It is not, it is sqrt 5 times I know which sides to compare because I drew a quick sketch of the two figures.
*June 2, 2015*

**Math**

V to W = sqrt (25+0) = 5 R to S = sqrt (100+0) = 10 W to X =sqrt(49+9) = sqrt(58) S to T = sqrt(169+121) = sqrt (5*58) oh my :(, not twice, would be sqrt 4*58 if similar
*June 2, 2015*

**Math**

agree
*June 2, 2015*

**physics**

m g /area m = .050 KG g = 9.8 m/s^2 area = pi r^2 = pi (9 *10^-6) meters^2 so p = .0173 * 10^6 N/m^2 or Pascals = 1.73 * 10^4 Pascals or around .2 atmospheres
*June 2, 2015*

**physics**

That makes no sense to me at all. The total mechanical energy is the sum of the kinetic and potential energies.
*June 2, 2015*

**Algebra**

t = k/r 12 = k/60 so k = 12*60 then t = 12*60/85 = 8.47
*June 2, 2015*

**Physics**

well, the second equation is -A cos 41.9 + B cos 25.2 = 0 which is B = A(cos 41.9 / cos 25.2) so use that for B in the first equation
*June 2, 2015*

**Physics**

assume if A is in Quadrant 2 then B is in quadrant 1 (or the opposite, does not matter) sum of y components = 0 A sin 41.9 + B sin 25.2 - 25.8 = 0 sum of x components = 0 -A cos 41.9 + B cos 25.2 = 0
*June 2, 2015*

**physics**

d = .8 meter so F = G *55*70 /(.64) where G = 6.67*10^-11 m^3 /(kg s^2)
*June 2, 2015*

**physics**

force = 2*9.81 - 7 = 12.6 Newtons accelerated mass = 5 + 2 = 7 a = F/m = (12.6/7) m/s^2
*June 2, 2015*

**Math**

well, look at what happens to point (-1,0) it remains at (-1,0) when reflected around y=x+1 because it is on that line so just reflect it about y = x+3 drawing the graph I see it went left 2 from -1 and up the same amount, 2, from 0 so left 2 and up 2 :)
*June 2, 2015*

**Math help please**

40/80 = .5 20/80 = .25 60/80 = .75 so steepest 3/4 D
*June 2, 2015*

**Math**

believe me, it is much less confusing using another symbol for x^2 then replacing it at the end.
*June 2, 2015*

**Math**

let f(x) = z = x^2 so x = sqrt z and z always positive y = 3 (-4 sqrt z-2)^2 + 5 y = 3(16 z + 16 sqrt z +4) + 5 y = 48 z + 48 z^.5+ 17 y = 48 f(x) +48 f(x)^.5 + 17
*June 2, 2015*

**Math**

Steve and I both said the same thing in different ways. Here is another. like when is 2x+3 = 0 ??? when x = -3/2 so what is f(0) it is 0 so when x = -3/2 then g(x) = 0
*June 2, 2015*

**Math**

if x = -1, 2x+3 = 1 and -f(1) = -4 if x = 0, 2x+3 = 3 and -f(3) = -10 etc
*June 2, 2015*

**Math**

Huh? If that is a table of values of x and y, then y = 5 when x = 3
*June 2, 2015*

**Physics**

I guess you mean g = 10 m/s^2 Work done = increase in potential = m g * increase in height = 5 kg * 10 m/s^2 * 10 m = 500 Newton meters = 500 Joules
*June 2, 2015*

**Math (check answers)**

5 d^(6-12) = 5 d^-6 yes
*June 1, 2015*

**civics**

I think D is the correct answer. but knowing the speaker, it might be C :)
*June 1, 2015*

**algebra--1 question**

No, read above, a
*May 31, 2015*

**algebra--1 question**

check 14*75 = 1050 300 + 750 = 1050 sure enough
*May 31, 2015*

**algebra--1 question**

x^3+0x^2-7x+6/(x+3) = x^2-3x+2 which is a
*May 31, 2015*

**Algebra II**

agree but check as follows 1 + 5 (6-8) = 2 - (6+5) ???? 1 - 10 = 2 - 11 ??? -9 = - 9 Yes :)
*May 31, 2015*

**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*