Friday

May 29, 2015

May 29, 2015

Total # Posts: 21,075

**Int. science**

Oh, please guess !
*October 2, 2014*

**statistics**

I think you mean standard deviation of 9 http://davidmlane.com/hyperstat/z_table.html
*October 2, 2014*

**Distributive Property Algebra**

8(6 - 2) = 8(6) - 8(2) by distributive property of multipication = 48 - 16 = 32 --------------------------- You could also say 8*4 = 32 but that does NOT USE distributive property. ------------------------- 7 c + 7*4 by distributive property then = 7 c + 28
*October 2, 2014*

**science**

I am assuming that you are correct; the water evaporates
*October 2, 2014*

**physics**

That depends If you are in an car: If it is taking off from a stop light and accelerating forward then Thrust is greater than Drag If it is cruising along at constant velocity then Thrust forward equals drag back If you take your foot off the gas and coast then Thrust becomes ...
*October 2, 2014*

**physics**

drag is normally opposite to velocity.
*October 2, 2014*

**Algebra**

You are welcome.
*October 2, 2014*

**Algebra**

5m and 3 m are indeed like terms (combine like terms to make 8 m + 6 p + 4)
*October 2, 2014*

**Math**

(A) 2/5 (B) 2/5 = 24/60 (C) 2/5= what/35 multiply 2/5 by 7/7 and get 14/35 so 14
*October 2, 2014*

**Intro to Physical Science**

m g h = potential energy at top = 100 * 9.81 * 12 = 11,772 Joules loses 3550 Joules so (1/2) (100) v^2 = 11,772 - 3550 = 8222 Joules v = 12.8 m/s
*October 2, 2014*

**Math**

17 * 85/6
*October 2, 2014*

**n2 maths**

pi (25)^2/4 * 40 = n (4/3) pi (3)^3 6250 = 36 n
*October 2, 2014*

**math n2**

tan 58 = h/380
*October 2, 2014*

**physics**

d = .5 a t^2 a = 6/t .01 = .5 (6/t)t^2 = 3 t t = .00333 s F = change in momentum/change in time = .45 *6/.00333 = 810 Newtons
*October 1, 2014*

**physics**

10^3*10^8 = 10^11
*October 1, 2014*

**Physics**

h = (1/2) g t^2 in metric, g = 9.81 meters/s^2 in English g = 32 feet/second^2
*October 1, 2014*

**calc / physics**

yes yes
*October 1, 2014*

**Algebra**

- x^4 always - (-x)^4 always + x either -x either
*October 1, 2014*

**Math**

f(8+h) = sqrt (8+h) - 8 f(8) = sqrt(8) - 8 subtract sqrt (8+h) -sqrt (8) but d/dh (8+h)^.5 = .5 (8+h)^-.5 so sqrt (8+h) = sqrt 8 + .5 h/sqrt(8+h) subtract sqrt 8 .5 h/sqrt(8+h) divide by h .5/sqrt (8+h) let h -->0 .5/sqrt 8
*October 1, 2014*

**math**

x = [ -5 +/- sqrt(25 + 8) ]/4 = [ -5 +/- sqrt (33) ]/4
*October 1, 2014*

**physics**

a = change in velocity / change in time -.87 = change in velocity / 3.8 so change in velocity = -3.3 m/s
*October 1, 2014*

**Chem 400**

It is there 0.6548 g/mL *10^-3 mL/ uL =.6548 *10^-3 g/uL
*October 1, 2014*

**Chem 400**

hexane is 86 g/mol we have 55 uL *.6548 *10^-3 g/uL = 36*10^-3 g 36*10^-3/86 =4.2 * 10^-4 mol * 6*10^23 = 2.51*10^20 molecules of hexane now just add up the protons in a molecule and divide. It is C6H14 C has 6 each and H has 1 each
*October 1, 2014*

**math**

-50 3/4 = -203/4 = - 5075/100 -6.05 = -605/100 100 = 10,000/100 so (-5075 -605 + 10,000)/100 = 4320 / 100 = 43.2
*October 1, 2014*

**Printing press**

Good grief !!! Google Gutenburg
*October 1, 2014*

**Math**

8 j + 4 d = 64 4 j + 8 d = 92 multiply first eqn by 2 16 j + 8 d = 128 4 j + 8 d = 92 --------------- subtract 12 j = 36 j - 3 dollars per jump rope then d = 10 dollars per doll You can do it now
*October 1, 2014*

**math**

7 a + 3 s = 1625 s = 2 a so 7 a + 3 (2 a) = 1625 7 a + 6 a = 1625 13 a = 1625 a = 125 so s = 250
*October 1, 2014*

**Chemistry**

Huh ?? a mole of anything is about 6*10^23 of them like a dozen is 12 of something 2.65*10^15 ----------- 6 * 10^23 = .442 *10^-8 = 4.42 * 10^-9 moles
*October 1, 2014*

**Math**

546*714 /(42*42) = 221 but, is that exact? 546 / 42 = 13 714 / 42 = 17 yes, tiles do not have to be cut.
*October 1, 2014*

**math**

100 + 10(150 - 50)
*October 1, 2014*

**Math help!**

c - distributive d - commutative
*October 1, 2014*

**History**

I am no scholar of the period but am having trouble imagining the Italian cities working together to do this. Do you mean Venice and Genoa cooperating ?
*October 1, 2014*

**chemistry**

Xe = 131 g/mol F = 19 g/mol so XeFn = (131 + 19 n) g/mol or (131+19n)g / 6*10^23 molecules but this stuff is .368 g/9.03*10^20 molecules .368/9.03*10^20 = (131+19n) /6*10^23 131+19 n = 244.5 g/mol 19 n = 113.5 n = 6 so XeF6
*October 1, 2014*

**History**

That is just a symptom of the importance though. There is much more but I would have to write a book for you.
*October 1, 2014*

**History**

LOL gmta
*October 1, 2014*

**History**

What language do they speak there now?
*October 1, 2014*

**Math (for Damon)**

You are welcome :)
*October 1, 2014*

**Math (for Damon)**

weight of single Steven box (English unclear) = s so weight of a Nathan box = s+12 so weight lifted by Nathan = 13(s+12) agree but sentence could mean total weight of boxes lifted by Steven = s then each steven box weighs s/15 then a nathan box weighs (s/15) + 12 and total ...
*October 1, 2014*

**English**

can play looks like a compound verb to me
*October 1, 2014*

**Math**

change in x = 3 change in y = 5 hypotenuse = sqrt (9+25) = sqrt (24) = sqrt (4*6) = 2 sqrt 6
*October 1, 2014*

**Math ????**

What do you want to know? The slope between those two point? the distance between them?
*October 1, 2014*

**physics**

v = Vi + a t =3.25 + 3.2*4.4
*October 1, 2014*

**Math plz.**

z(1-2+4) + 6 3 z + 6
*October 1, 2014*

**Math question? :c**

7*c + 7*4 = 7 c + 28
*October 1, 2014*

**math**

2588 - 188 = 2400 2400 / 24 = 100 per payment
*October 1, 2014*

**math**

.75 p = p - 180 yes I do not know what the second question is.
*October 1, 2014*

**1 math question**

8*6 = 48 8*2 = 16 so 8(6-2) = 48-16 = 32
*October 1, 2014*

**physics**

here http://en.wikipedia.org/wiki/Geostationary_orbit 35,786 kilometers above earth
*September 30, 2014*

**physics**

look up geostationary satellite
*September 30, 2014*

**physics**

F = m v^2/r
*September 30, 2014*

**Algebra**

Yes.
*September 30, 2014*

**Algebra**

(-7,3) I think I do not do interval notation either.
*September 30, 2014*

**Algebra**

(x+2) < 5 and -(x+2) <5 x < 3 and (x+2) > -5 x < 3 and x > -7 which is -7 < x < 3
*September 30, 2014*

**Physics-Intro**

good grief, I have not seen those units for a while still F = m a force and weight in pounds, mass in slugs acceleration in ft/s^2 F = 25,000 * 28 = 700,000 pounds
*September 30, 2014*

**physics**

.424 * 10^8 m/s = 4.24 * 10^7 or a bit over a tenth of the speed of light.
*September 30, 2014*

**Algebra 2 Answer Check**

2 y = -5 x + 8 y = -(5/2) x + 4 slope = -5/2 so slope of perpendicular = 2/5 y = -(2/5) x + b 3 = -(2/5)5 + b 3 = -2 + b b = 5 y = -(2/5) x + 5
*September 30, 2014*

**Algebra 1**

1 a try x = -1 1 </= -1 nope b x = -1 works but x = 10 fails totally c x^2 </= 23.25 x^2 x^2 always + so this works by the way d is 4 x^2 -24 x + 36 >/= 4 x^2 - 3 -24 x + 39 >/= 0 nope
*September 30, 2014*

**Typo**

If you are really serious about only 11 meters^2 then (w+6)w = 11 w^2 + 6 w - 11 = 0
*September 30, 2014*

**Physics**

F = m a Ft = tug force = - Fa asteroid force 3360 vt + 6300 va = 0 momentum remains 0 490 = 3360 at -490 = 6300 aa at = .146 m/s^2 aa = -0.778 m/s^2 vt = 0 + .146 t va = 0 - .778 t position t = .5 (.146)t^2 430 - position a = .5 (-.778)t^2 they are headed toward each other so ...
*September 30, 2014*

**Trigonometry**

if theta is between 0 and -90 (quadrant 4) the sin is negative. Therefore we only look at quadrant one. sin^-1 0.95 = 71.8 degrees
*September 30, 2014*

**chemistry**

first balance 2 NaClO + H2O --> 2 Na+ +2OH- + Cl2 + O2 How many mols of NaClO ? Na = 23 g/mol Cl = 35.5 O = +16 so NaClO = 74.5 g/mol 2 NaClO = 149 g then grams of NaClO = .0585 *1.12*15 = .983 grams of NaCl .983/74.5 = .0132 mols of NaClO we get half as many mols of O2 so ...
*September 30, 2014*

**Algebra**

L = w + 4 L w = 165 (w+4)w = 165 w^2 + 4 w - 165 = 0 (w+15)(w-11) = 0 w = 11
*September 30, 2014*

**Physics**

phase 1 v = 5 t , slope up of 5 up to Vi = 25 phase 2 v = constant = 25 from t = 5 to t = 20 phase 3 v = 25- 5(t-20), slope down of -5
*September 30, 2014*

**Pre-Calculus/Trigonometry**

You are welcome :)
*September 30, 2014*

**Pre-Calculus/Trigonometry**

would it be like this for a, and if so how would i continue that? (f o g)(x)= 1/[(f o g)(x)-5]? ======================= no, just do what it says f (g(x)) use g(x) = (x^2+2) for argument of f in other words f (x^2+2) = 1/[ (x^2+2) - 5 ]
*September 30, 2014*

**Pre-Calculus/Trigonometry**

replace x by x^2+2 1/[ (x^2+2) -5 ] = 1/(x^2 - 3) b. f(6) = 1/1 = 1 g(1) = 1+2 = 3
*September 30, 2014*

**precal**

9 9r 9r^2 9r^3 -72 = 9 r^3 r^3 = -72/9 now work back a9 = 9/r a8 = 9/r^2 a7 = 9/r^3 interesting a7 = 9/r^3 = (9)(-9/72) = -81/72
*September 30, 2014*

**physics**

I could swear I did this one yesterday :( ball 1 d = distance down d = .5 g (t+1)^2 ball 2 d = 40 t + .5 g t^2 so .5 g (t^2 + 2 t + 1) = 40 t + .5 g t^2 put in whatever you use for g (9.81, 9.8 or 10) and solve the quadratic
*September 30, 2014*

**ALgebra 2**

From 0 go left 1/2 then go left another 3/4 see that you are now at -1 1/4
*September 30, 2014*

**ALgebra 2**

-2/4 - 3/4 = -5/4 = -1 1/4 Sketch this on a number line !!!!
*September 30, 2014*

**mathematic**

p = r - c p = 150 n - 850 - 76 n p=74n-850
*September 30, 2014*

**math exponential function**

450 (1.06)^(2n) = 477 1.06^2n = 1.06 n = 1/2 year
*September 30, 2014*

**Calculus**

ln y = x ln 2 1/y dy/dx = ln 2 dy/dx = y ln 2 or dy/dx = 2^x ln 2
*September 28, 2014*

**physics**

time for first rock -20 = -5 t^2 t = 2 seconds to fall so t for second ball = 2 - 1 = 1 second -20 = -Vi t + -5 t^2 20 = -Vi + 5 Vi = -15 m/s (the - sign means speed is down)
*September 28, 2014*

**physics**

Da = Db same distance total time a = time b + delay b we want time b Car A accelerate phase: vi = aA delayb Di = .5 aA delayb^2 constant speed phase Da = Di + vi t = .5 aA delayb^2 + aA delayb timeb Car B Db = .5 aB timeb^2 now Da=Db so .5 aA delayb^2 + aA delayb timeb = .5 aB...
*September 28, 2014*

**physic**

first vertical problem 45 = 4.9 t^2 t = 3.03 seconds to fall distance ball is from building = 3.03*5 = 15.15 distance man must run = 15.15 - 6 = 9.15 time man has = 3.03-.3 = 2.73 seconds 9.15 = .5 a (2.73)^2 solve for a
*September 28, 2014*

**trigo**

cos 3 x = 4 cos^3 x - 3 cos x
*September 28, 2014*

**SCIENCE - PLEASE HELP PLESE**

4) Multiply 4.135 x 4.688 888 887 m x 8.7m round your answer to the correct number of significant figures. ============================ You only have 2 sig figs because you said 8.7 not 8.70000000 so 19.388555555 is 19 <-------answer
*September 28, 2014*

**SCIENCE - PLEASE HELP PLESE**

3) Round 3155.24m, 8.777 73 cm, and 93.775 57 kg to one less significant figure than they each have currently. ==================== 3155.24 4 is less than 5 so 3155.3 3<5 so 8.7777 93.77557 7>5 so 93.7756
*September 28, 2014*

**SCIENCE - PLEASE HELP PLESE**

2) Find the weight of a 12.25 kg dog. Round your answer to the correct number of significant figures. Use weight=massxfree-fall acceleration. g is different in different places on earth. We need it to four significant figures because your mass is to four sig figs. I will call ...
*September 28, 2014*

**SCIENCE - PLEASE HELP PLESE**

1) Round 578.683 m, 47.3333 kg, and 789.5 cm to four significant figures. 0,1,2,3,4 round down 5,6,7,8,9 round up 578.6 83 8 is greater than 4 so this becomes 578.7 meters 47.33 33 3 is less than 4 so this becomes 47.33 kilograms 789.5 cm This already has four significant ...
*September 28, 2014*

**trigo**

h = L (1-cos T) geometry exact cos 2A = 1 - 2 sin^2 A identity so cos T = 1 - 2 sin^2 (T/2) h = L [ 1 - (1 -2 sin^2 (T/2) ] = L [2 sin^2 (T/2) ] = 20 sin^2 (T/2)
*September 28, 2014*

**physics**

2.4*84
*September 28, 2014*

**physics**

84*.24
*September 28, 2014*

**geometry**

height = h = 280/40 V = (1/3)(40)(h) the volume of any pointy thing with straight sides = (1/3) base area * height
*September 28, 2014*

**math**

in the ten based number system: To multiply by ten, add a zero To divide by ten, move decimal point one space left 200 / 10 = 20.0 = 20
*September 27, 2014*

**physcis**

.926 = (1/2)(9.8) t^2 solve for t u = 18.3/t
*September 27, 2014*

**physics**

r = 33*10^6 + 6.37*10^6 2 pi r = circumference of orbit v = 2 pi r/(24 h * 3600 s/h) Ac = v^2/r
*September 27, 2014*

**physics**

1.1 = Vi t - 4.9 t^2 t = 4.4/u but u = Vi because tan 45 = 1 1.1 = u t - 4.9 t^2 1.1 = u t - 4.9 (4.4^2)/u^2 1.1 u^2 = u^2 (4.4) - 94.9 3.3 u^2 = 94.9 u = Vi = 5.36 m/s sqrt(u^2+Vi^2) = 7.58 m/s
*September 27, 2014*

**physics**

45 F = 30*(45-15)
*September 27, 2014*

**physics**

200*10^3 = .2*10^6 m high R earth = 6.38*10^6 so R = 6.58 * 10^6 meters G = 6.67384 × 10-11 m3 kg-1 s-2 earth mass = Me = 5.97*10^24 kg m v^2/R = G Me m /R^2 v^2 = G Me/R = 6.67 * 5.97 /6.58 * 10^(-11+24-6) = 6.05 * 10^7 = 60.5 * 10^6 so v = 7.78*10^3 = 7,780 m/s (PART B...
*September 27, 2014*

**physics**

a = change in velocity / change in time = -16.7 / t t = distance/ average speed = .67/8.35 = .0802 second so a = -16.7 / .0802 = -208 agree F = m a = 42 * -208 = -8736 Newtons AGREE
*September 27, 2014*

**Math**

Try the rest now.
*September 27, 2014*

**Math**

10 balls at start 1 prob black, white, red = 3/10 * 4/9 * 5/8 2 prob black, red, white = 3/10 * 5/9 * 4/8 same as above 3 prob white, black, red = 4/10 * 3/9 * 5/8 same again 4 prob white, red , black same 5 prob red , white, black same 6 prob red, black, white same so 6 * 3/...
*September 27, 2014*

**Engineering science**

fresh water is about 1 kg/Liter so m g h/t = 9000 kg * 9.81 * 70/3600 seconds = 1717 Watts done = 1717 Joules/second * 3600 seconds/hr = 6,180,300 Joules/hour = 1717Joules/second*60 s/min = 103,020 Joules/min
*September 27, 2014*

**science**

3000*1 = F = 4000 * x x = .75 m/s^2
*September 27, 2014*

**chemistry**

. 4 mol/liter = .0004 mol/mL 30 * .0004 = 0.012 mol NaOH .012 mol NaOH in 100 mL is .12 mol/liter
*September 27, 2014*

**physics**

Gravitational force = G mplanet m/d^2 G = 6.67384 × 10-11 m3 kg-1 s-2 so FB = 6.67384 × 10-11 m3 kg-1 s-2 MB*6930/(3.01*10^6)^2
*September 27, 2014*

**physics**

FB = G MB 6930/(9*10^12) FA = G MA 6930/(9*10^12) MA = (9*10^12/6930 G) FA MB = (9*10^12/6930 G) FB ---------------------------- MA - MB = (9*10^12/6930 G)(FA-FB)
*September 27, 2014*

**chemistry**

100 (4.78/6.67)
*September 27, 2014*