Friday

January 30, 2015

January 30, 2015

Total # Posts: 20,428

**chemistry**

MgCl2 HUH? Mg is +2 and Cl is -1
*August 23, 2014*

**Algebra**

yes, that is just a reversal of order which is commutative. It will work until you get to matrix multiplication.
*August 23, 2014*

**Algebra**

agree
*August 23, 2014*

**American Government**

You are welcome. I think on the average over the range of issues the bar has more influence. I personally resent all of these organizations and their influence.
*August 23, 2014*

**American Government**

I decline to give my opinion because I consider it embarrassing.
*August 23, 2014*

**chemistry**

you only have one H2O on the sulfate so I would call it a monohydrate Are you sure it is not 7H2O ???? instead of /H2O ???? the would make it D
*August 23, 2014*

**chemistry**

B is wildly wrong !!! C is also Wildly wrong for the same reason. Hydrogen reacts. Helium reacts with essentially nothing because that first level is full of its two electrons D is just crazy. Helium is our second element with two protons and two electrons.
*August 23, 2014*

**chemistry**

mass does not change in a chemical reaction
*August 23, 2014*

**Government**

You are welcome :)
*August 23, 2014*

**Government**

http://www.washingtonpost.com/wp-dyn/content/article/2009/07/05/AR2009070502770.html
*August 23, 2014*

**Physics**

does not matter what the charge on B is, call it -1 and call k = 1 To the left 2/(1)^2 + 1/(1)^2 = 3/1 to the left so we need 3 to the right Qd/4^2 = 3 Qd = 16*3 = 48
*August 23, 2014*

**College Algebra 1**

10 x^2 - 41 x + 21 = 0 (5 3) (2 7) ??? yes, 6 and 35 (5x-3)(2x-7) = 0 x = 3/5 or x = 7/2
*August 23, 2014*

**math**

yes
*August 23, 2014*

**math**

hint find common factor
*August 23, 2014*

**math**

you have 4 choices for the first digit 3 for the second 2 for the third left with one 4*3*2 = 24
*August 23, 2014*

**science**

I do not believe it can. The only thing I can think of is that you are dealing with two different isotopes of silver.(107 grams/mol and 109 grams/mol)
*August 23, 2014*

**math**

a = b/2 b = 2 a 5 b = 10 a half of 5 b = 5 a
*August 23, 2014*

**Precal**

Use your calculator cos 75 = cos 83 = cos 91 = cos 99 = cos 107 = cos 115 = cos 123 = cos 131 = cos 139 - cos 147 = now add to get a :)
*August 23, 2014*

**statistics**

http://www.alcula.com/calculators/statistics/correlation-coefficient/ http://www.alcula.com/calculators/statistics/linear-regression/
*August 23, 2014*

**statistics**

How about trying yourself instead of asking us to do them all?
*August 23, 2014*

**Algebra**

You are welcome :)
*August 23, 2014*

**Algebra**

9^ means 9^.5 or 9^2 or 9^.7315 or what? from your answer I am guessing 9^2 11 (81 - 25) /(12) = 51 1/3 yes
*August 23, 2014*

**Algebra**

Correct
*August 23, 2014*

**Algebra**

You are welcome.
*August 23, 2014*

**Algebra**

yes, order does not matter.
*August 23, 2014*

**Earth Science Continued**

For 1 I would have picked B but if B is wrong go with D 3. B yes 5. C yes, it is an example of the theory in action
*August 23, 2014*

**College Algebra 1**

1 = 1^2 25 z^2 = (5z)^2 so (1-5z)(1+5z)
*August 23, 2014*

**Algebra**

well, yes, but they asked for the expression: $25 + 6($14) not the result: answer = $109
*August 23, 2014*

**Algebra**

You are welcome :)
*August 23, 2014*

**Pre-cal**

one way: cos 75 + cos 83 + .....cos 147 = a sin 75 + sin 83 + .... sin 147 = b tan theta = b/a r = sqrt (a^2+b^2)
*August 23, 2014*

**Algebra**

.01 x + .04 (5-x) = .02 (5)
*August 23, 2014*

**nitw - Incomplete question**

You need the coef of friction or the time or the deceleration
*August 23, 2014*

**American Constitutional Law**

I assume we are talking about the national guard which is usually run by the state but can be called up by the federal government if needed. Therefore I think C see: http://www.arng.army.mil/aboutus/history/Pages/ConstitutionalCharteroftheGuard.aspx
*August 23, 2014*

**American Constitution Law**

see answer above http://www.arng.army.mil/aboutus/history/Pages/ConstitutionalCharteroftheGuard.aspx
*August 23, 2014*

**Math**

1 Mas + 1.2 Mas = 550 Mas = 550 / 2.2
*August 23, 2014*

**physics**

x axis from center A to center B Ball A before Vx = 10 cos 60 = 5 sqrt 3 Vy = -10 sin 60 = -5 let m = 1 kg Ke = (1/2)(100) = 50 Joules Ball B before Vx = 0 and Vy = 0 and Ke = 0 Ball 1 after Vx1 Vy1 Ke1 =(1/2)(Vx1^2+Vy1^2) Ball 2 after Vx2 Vy2 (has no Vy because hit in x ...
*August 23, 2014*

**physics**

Negative wavelets. The original Huygens Principle does not clearly account for the wave direction. The important point is that the wavelet phase must be considered. However, the diagram below shows that additional negative wavelets easily solve this problem. The use of black ...
*August 23, 2014*

**PHYSICS**

F cos 30 = 30
*August 23, 2014*

**Physics**

F = G M1 M2 / d^2
*August 23, 2014*

**maths**

6/20 = 30/100
*August 23, 2014*

**Math**

multiply both sides by 6 y 8 + 15 = 6 y 6 y = 23 y = 23/15
*August 23, 2014*

**algebra**

I bet you mean 5 x^2 / (x^3-x^2) 5 x^2 /[ x^2(x-1) ] 5 / (x-1)
*August 23, 2014*

**math**

5^2 = 2.5^2 + h^2 h^2 = 25 - 6.25
*August 23, 2014*

**science**

I have no idea. There are two naturally occurring isotopes of silver, 107 and 109, but that is not enough difference.
*August 23, 2014*

**Algebra**

If you meant to type (3/5)^3 then you are right.
*August 23, 2014*

**math**

pi r^2 - 9 4 pi - 9 about 3.566370614
*August 22, 2014*

**I have a pretty hard one**

5600/27 is a common fraction
*August 22, 2014*

**I have a pretty hard one**

there is a trick to finding the fraction for a repeating decimal by the way. Google repeating decimal in this case for example .407407407 ---- 1000 x = 407.407407407..... x = .407407407.... so 999x = 407 x = 407/999 = 11/27
*August 22, 2014*

**I have a pretty hard one**

oh 70 / (45/100 *75/100) 70 * 100 *100 / (45 * 75) 14 * 20 * 100 / (9 * 15) 14 * 4 * 100 / (9 * 3) 5600 / 27 = 207 11/27 because 207 * 27 = 5589 and 5600 - 5589 = 11
*August 22, 2014*

**I have a pretty hard one**

.45 * .75 * n = 70 n = 70/ (.45*.75) n = 70 / .3375
*August 22, 2014*

**math**

.24 n = 45 so n = 45/.24
*August 22, 2014*

**Physical science**

http://dwb4.unl.edu/Chem/CHEM869R/CHEM869RLinks/www.nidlink.com/7Ejfromm/arrhenius.htm
*August 22, 2014*

**math mental math**

as I said down below 17 - 2 + 2 + 38 = 15 + 40
*August 22, 2014*

**physics**

been there, done that
*August 22, 2014*

**physics**

54 km/h * (1 h/3600 s)*(1000 m/km) = 15 m/s 15 m/s / 5 s = 3 m/s^2 (1/2) m v^2 Joules (1/2) m v^2 Joules/15seconds ---> Watts
*August 22, 2014*

**math**

DRAW A PICTURE The change of an integral at the right hand limit is the area defined by the height , f(x), times dx In other words the answer is f(2sqrt2) 2sqrt [2sqrt 2)^2+1] = 2sqrt(8+1) =2* 3
*August 22, 2014*

**MATH HELP**

17 - 2 + 2 + 38 = 15 + 40
*August 22, 2014*

**MATH HELP**

I would add 15 to 40
*August 22, 2014*

**Related rates math in calculus**

L = 18-2x w = 18-2x h = x V = x(18-2x)^2 dV/dx = 0 for max or min 0 = x (2)(18-2x)(-2) + 1 (18-2x)^2 0 = -4x (18-2x) + 324 - 72 x + 4 x^2 0 = -72 x + 8 x^2 + 324 -72 x + 4 x^2 0 = 12 x^2 - 144 x + 324 0 = x^2 - 12 x + 27 0 = (x-3)(x-9) x = 3 or 9 but 9 will not work (is V=0) ...
*August 22, 2014*

**math**

You are welcome :)
*August 21, 2014*

**math**

100,000 to 999,999 is one hundred thousand to nine hundred and ninety nine thousand nine hundred and ninety nine.
*August 21, 2014*

**Earth Science**

He said .... then .... experimentation supported Amit agrees :)
*August 21, 2014*

**Earth Science**

The scientist SUSPECTED that acid might be harmful. Therefore experiment to see if CO2 in water harms shells
*August 21, 2014*

**math**

32 gal/min * (60 min/ hr) * (4 qt/gal) = 7680 qt/hr notice that I multiply by things that are the same top and bottom but different units 60 min = 1 hr 4 qt = 1 gal I do the numerator and denominator to make the units I want to get rid of cancel and leave the new ones that I ...
*August 21, 2014*

**math - and so on?**

You did not say what he charged per mile after 2 miles
*August 21, 2014*

**life sciences**

http://humanorigins.si.edu/evidence/human-fossils/species/australopithecus-sediba
*August 21, 2014*

**Math**

2 L + 2 w = 12 so L = 6-w area = A = L w L w = (6-w)w = A w^2 - 6 w = -A find vertex by completing square w^2 - 6 w + 9 = -A+9 (w-3) = -1(A-9) max at w = L =3 and area = 9 By the way, you could have guessed that our rectangle would turn out to be a square.
*August 21, 2014*

**Math**

(y-4)/(x-0) = (-1-4)/(1-0) (y-4 ) = -5 x y = -5 x + 4 now sketch a graph of that
*August 21, 2014*

**ALGEBRA**

12 marbles first draw 3/12 = 1/4 second draw 5/11 1/4 * 5/11 = 5/44
*August 21, 2014*

**math**

if p </= 30 , then c = 750 if p >30 then c = 20 (p -30) + 750
*August 21, 2014*

**college algebra**

A 1/12 pool / hr B 1/24 pool / hr together 3/24 pool/hr so 24/3 = 8 hr/pool
*August 20, 2014*

**algebra**

sketch a graph !!! looks like a straight line with slope = -1 to me
*August 20, 2014*

**Math**

two are already decide. You have two more flips. What is the chance of getting one heads and one tails out of those two flips ? You have four possibilities HH HT TH TT two of those four work, TH and HT so I get 1/2
*August 20, 2014*

**physics**

Try using these: https://answers.yahoo.com/question/index?qid=20081123194116AA3FxdL use that for the average speed and standard deviation. Then he range is so narrow I would assume a normal distribution and use that average and standard deviation in the normal table rather ...
*August 20, 2014*

**calc**

A = 2 x (a^2+x^2)^.5 dA/dx = 2 x (2x)(.5)(a^2+x^2)^-.5) + 2 (a^2+x^2)^.5 = 0 for max or min
*August 20, 2014*

**static and dynamics**

force down slope = m g sin 34 so friction force = force down slope if it is not accelerating down slope.
*August 20, 2014*

**math**

z 2 x y z + 2 + x + 7 = 13 z is even or z = 2 w 2w + 2 + x + 7 = 13 2 w + x = 4 x must also be even or 0 x = 0 then w = 1 if x = 2 then w = 1 so if x = 0 then w = 2 2227 4207
*August 20, 2014*

**math**

4915/72 =
*August 20, 2014*

**math**

40 + 20 = 60 60 - 28/7 = 60 - 4 = 56 56 + 30/5 = 56 + 6 = 62 62 - 3 = 59
*August 20, 2014*

**algebra HUH??**

meaningless
*August 20, 2014*

**physics**

Calculate pressure halfway up the wall p = 1000 kg/m^3 * 10 m/s^2 * 2 m thrust on one wall = p * area
*August 20, 2014*

**physics what is side and length of bottom?**

.2 m square or .1 m square on bottom? I will assume bottom square size s and depth h pressure = density * g * h if h is .5 m (it is not clear what depth of alcohol is from sloppy wording of question. It is the depth that matters, not how high the container is off the ground.) ...
*August 20, 2014*

**Science**

24 g of Mg is how many mols of Mg ? so How many mols of O ? (Hint: MgO has exactly as many mols of O as of Mg , note of O at 16 g/mol, not O2 at 32 g/mol) so mass of O = mols of O * 16 g/mol
*August 20, 2014*

**Chemistry**

True :)
*August 20, 2014*

**Connexus**

If it were condensed it would be a liquid, not a gas.
*August 20, 2014*

**physics**

F = G Me m/R^2 = approximately m g because G Me/R^2 is pretty much constant around earth surface 1/R^2 Toward the center of mass of the object that is pulling it, for example toward earth center.
*August 20, 2014*

**physics/ basic of statics**

3 kg weighs 3*9.8 = 29.4 Newtons 5 kg weighs 5*9.8 = 49 Newtons say the 49 N force is in the x axis direction tthe 29.4 N force is 60 degrees toward the Y axis Sum of x forces= 49+29.4cos 60 = 63.7 N Sum of y forces = 29.4 sin 60 = 25.5 N magnitude = sqrt(25.5^2 + 63.7^2) = 68...
*August 19, 2014*

**Science**

I take that back, both question can be asked and then hypothesis posed: http://www.sciencebob.com/sciencefair/scientificmethod.php
*August 19, 2014*

**Science**

pretty much, although usually the word "hypothesis" is used instead of question. One tends to pose a hypothesis, then test so see if it works.
*August 19, 2014*

**math**

Remember back when when you were learning addition you had the commutative property of addition which means 2 + 3 is the same as 3 + 2 Now you are getting the same property for multiplication :)
*August 19, 2014*

**math**

you just did. The property means that 8 * 7 is exactly the same as 7 * 8 In other words the two factors commute, you can change their order without changing their product. This will be true until you get to multiplying matrices.
*August 19, 2014*

**math**

P = (60 - 22) x - 75 = 38 x = 75
*August 19, 2014*

**math**

(x+h)^2 + 2 = x^2 + 2 x h + h^2 + 2 the are getting you ready to find the derivative which is the limit as h -->0 of [f(x+h) - f(x) ]/h which here would be limit as h -->0 of (2 x h + h^2)/h or 2 x + h as h -->0 is 2x which is df(x)/dx
*August 19, 2014*

**science**

density is mass per unit volume if the volume of steel is the same and the mass more then the density of the steel is more. (strange by the way)
*August 19, 2014*

**physics**

dv/dt = -1/t^2 v = (1/t) + c 3 = 1 + c c = 2 v = (1/t) + 2 if t = 4 v = 2.25
*August 19, 2014*

**physics**

dv/dt = -kv dv/v = - k dt ln v = - k t + c e^ln v = v = e^(-kt +c) = e^c e^(-kt) when t = 0, v = Vo Vo = e^c e^0 = e^c so v = Vo e^-kt
*August 19, 2014*

**physics**

2 seconds rising and 2 seconds falling h = (1/2)g t^2 falling 10 = (1/2) g (4) = 2 g g = 5 m/s^2
*August 19, 2014*

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