Thursday

March 5, 2015

March 5, 2015

Total # Posts: 20,652

**math**

1 * 2^0 = 1 0 * 2^1 = 0 1 * 2^2 = 4 1 * 2^3 = 8 so 13
*November 26, 2014*

**math**

1.25 L + .75 s = 109.75 L + s = 105 so s = (105-L) so 1.25 L + .75 (105-L) = 109.75
*November 26, 2014*

**Physics**

Force * distance/ time 85 * 9.8 * 2.5 Joules/second or Watts
*November 25, 2014*

**math**

7 * x^.5 * x^.5 = 7 * x^1 = 7 x
*November 25, 2014*

**chemistry**

H is enthalpy but I do physics, not chemistry.
*November 25, 2014*

**chemistry**

And I still think it is Physics :)
*November 25, 2014*

**chemistry**

(for example solids to gasses :)
*November 25, 2014*

**chemistry**

Increasing entropy is increasing disorder. look here http://chemistry.about.com/od/workedchemistryproblems/a/Entropy-Change-Example-Problem.htm note - more spread out --> more entropy
*November 25, 2014*

**physics**

350/353 = .991 seconds
*November 25, 2014*

**physics**

353 m/s
*November 25, 2014*

**physics**

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe.html
*November 25, 2014*

**physics**

No, you must look it up
*November 25, 2014*

**physics**

That sounds good. I did not look up the speed of sound at that temp.
*November 25, 2014*

**physics**

that is the frequency 1.3 kHz =1300 Hz period = 1/frequency
*November 25, 2014*

**physics**

You will have to look up the speed of sound in meters/s, somewhere around 350, at 35 C ,call it v distance = speed * time (a) t = 350/v (b) period = T = 1/f wavelength = speed * period lambda = v /1300
*November 25, 2014*

**Science 1 easy question!!!!**

Sure, fine. Of course I do not know the exact words your text used but suspect you got them there.
*November 25, 2014*

**Science 1 easy question!!!!**

yes, that will do.
*November 25, 2014*

**math**

pi (Rout^2 - Rin^2) = 8.68 In other words just hollow out the shaft.
*November 25, 2014*

**Science 1 easy question!!!!**

yes, those are ions, not sharing, giving and grabbing
*November 25, 2014*

**math**

https://www.mathsisfun.com/definitions/triangular-prism.html
*November 25, 2014*

**Physics help**

D is rather orderly and counter to increasing entropy by throwing them all around the room.
*November 25, 2014*

**Maths**

AB up y axis from (0,0) s to (0,s) then BC right s (s,s) then CD down s to (s,0) then DA left to (0,0) O at (x,y) a = -x i - y j b = -x i + (s-y) j c = (s-x)i (s-y) j unknown d = (s-x)i - y j c + a - b = (s-x)i +(s-y)j-y j -(s-y)j = (s-x)i - y j (Caramba) so I get d = c + a - b
*November 25, 2014*

**finance**

for normal curve calculations I use: http://davidmlane.com/hyperstat/z_table.html
*November 25, 2014*

**Chemistry**

100 * 3.46 / 3.67
*November 25, 2014*

**Chemistry**

http://www.jiskha.com/display.cgi?id=1416948226
*November 25, 2014*

**Chemistry**

did that a few minutes ago
*November 25, 2014*

**Thermodynamics**

dQ/T is negative for part of the cycle and positive for another. Of course if you include the surroundings overall entropy shows its usual tendency to increase :)
*November 25, 2014*

**Chemistry**

2Zn + O2 ---> 2 ZnO Zn = 65 O = 16 ZnO = 81 g/mol 2.8 g / 81 g/mol = .0346 mol ZnO half as many O2 mols = .0173 mol O2 .0173 * 32 g/mol = .553 mol O2
*November 25, 2014*

**programming**

n = 0 1 read x n = n + 1 print x If n > 1, go down to 2 small = x large = x 2 If x</= small, then small = x If x>/= large, then large = x If n < 12 , go back up to 1 Print small Print large end
*November 25, 2014*

**physics**

P V = n R T so P1 V1 = P2 V2 2374 V1 = 14.7 * 194
*November 25, 2014*

**Maths**

You are welcome.
*November 25, 2014*

**Maths**

5/6 = 175/g 5 g = 6 * 175 g = 6 * 175 / 5
*November 25, 2014*

**finnce100**

Maybe sell calls at a strike above the present price. Use that income to buy puts at a strike price lower than present price. That limits your future gains to the amount between present and call strike but gives you protection against a catastrophic fall.
*November 25, 2014*

**math**

-2 p + 2 q
*November 25, 2014*

**Chemistry**

{OH][H] = 10^-14 [H] = 10^-14/10^-3 = 10^-14 * 10^3 = 10^-11 strong base
*November 25, 2014*

**math**

(7*5)^3 * (5*11) * 3^22 7^3 * 5^3 * 5^1 * 11^1 * 3^22 7^3 * 5^4 * 11 * 3^22
*November 25, 2014*

**MATH**

p = d p + d + q = 51 p + 10 d + 25 q = 573 cents so 2 p + q = 51 11 p + 25 q = 573 multiply the first equation by 25 and subtract 50 p + 25 q = 1275 11 p + 25 q = 573 -------------------- 39 p = 702 p = 18 etc
*November 25, 2014*

**Math**

4 sides 5 + 5 + 5 + 5 = 20 so 5 feet
*November 25, 2014*

**Chemistry**

H2 CO3 + Li OH acid + base = salt + water H+ ions are acid OH- ions are base so we have a pot with H+ and OH- ions we also have CO3-- ions and Li+ ions so we really have H2CO3 and LiOH carbonic acid and Lithium hydroxide H2CO3 + 2LiOH --> Li2CO3 + 2H2O
*November 25, 2014*

**Chemistry**

N = 14 g/mol O3 = 3*16 = 48 g/mol so NO3 is 62 g/mol so (NO3)2 is 124 g/mol 1.2017 * 124 =
*November 25, 2014*

**Chemistry**

[OH][H] = 10^-14 [OH] = (1/7.9)(10^-14/10^-7) = .127 * 10^-7 = 1.27 * 10^-8 a bit acidic
*November 25, 2014*

**1 Math question**

6+13 = 19 and it is about .60 over that
*November 25, 2014*

**Math! Need The Help!**

You are welcome.
*November 25, 2014*

**Math! Need The Help!**

12.4/6 = 2.06 10.58/5 = 2.12 14.11/9 = 1.57 15.47/8 = worse than 1.57 so C is the minimum unit price per box
*November 25, 2014*

**Math Help! ASAP!**

PsyDAG has it right. I did not read carefully enough. One in three.
*November 25, 2014*

**Math Help! ASAP!**

three homes to two cars is 3/2 I agree of course you would get the same answer if two of three homes had one car, but I suppose everyone could share :)
*November 25, 2014*

**Chemistry**

C2H4 + 3O2 --> 2CO2 + 2H2O ideally so for .0713 mol C2H4 we need 3*.0713 = .213 mol O2 so we do not have enough O2 so .156 mol O2 is limiting for .156 mol O2 we get (2/3).156 mol of CO2 or .104 mol of CO2 C = 12 g/mol O2 = 32 g/mol so CO2 = 44 g/mol 44 * .104 = 4.58 grams ...
*November 25, 2014*

**I need help in 6th math**

:), yes, I vote for 30 it is not 56 because we know Elizabeth has more than Rosalie
*November 25, 2014*

**I need help in 6th math**

E = (17/10) R E = 51 so (17/10) R = 51 R = 510/17 = 30
*November 25, 2014*

**Math**

log 45 = log 5 + log 9 = log 5 + 2 log 3 sorry, I need log 5, not log 2
*November 25, 2014*

**pre calc**

10 = (1/400) x^2 - 20 x ??? you did not use parenthesis so I assume this 4000 = x^2 - 8000 x x^2 - 8000 x - 4000 = 0 x = [ 8000 +/- sqrt(64^10^6+16000) ]/2 x = nah, impossible you must mean f(x) = x^2 /(400 - 20 x) 10 = x^2 / (400 - 20 x) 4000 -200 x = x^2 x^2 + 200 x - 4000...
*November 25, 2014*

**Basic tech**

I assume no friction, so the thing is accelerating F = m a F = 20 a a = F/20 distance = (1/2) a t^2 10 = .5 * a * 25 a = 20/25 = 4/5 = .8 m/s^2 so F = 20 a = 160 Newtons (1) work = 160 * 10 = 1600 Joules (2) that work is the enegy used (3) power = energy/time = 1600/5 = 320 Watts
*November 25, 2014*

**Math**

y = 0 x + 60
*November 25, 2014*

**Physics Collision problem**

original x momentum = 238 * 4.8*10^5 original y momentum = 0 final y momentum is still zero 0 = 234 Vt + 4 Vhe final x momentum is still 238 * 4.8*10^5 = 234 Ut + 4 Uhe but we know Uhe = 1.2 *10^7 cos 36 = you do it Vhe = 1.2 *10^7 sin 36 = you do it Then go back and solve for...
*November 25, 2014*

**physics**

He has no kinetic energy when he starts the jump and none when he gets to the lowest point. therefore all potential energy lost m g (Ho-h) goes into (1/2) k x^2 x = 46 - 9 - h = 37 - h m g (46-h) = (1/2)k(37-h)^2 61 * 9.8 (46-h) = 38 (37-h)^2
*November 25, 2014*

**Maths**

3 * 1 = 3 3 * 2 = 6 3 * 4 = 12
*November 25, 2014*

**maths**

6*6 = 36 7*7 = 49 the total weight went up by 13 pounds when we added the seventh ball.
*November 25, 2014*

**Physics**

before North (y) momentum =2300(14) - 1600 (16) cos(270-225) = 32,200 - 18,101 = 14,098 kg m/s East(x) momentum = 0 =18,101 = -18,101 after same momentum, but mass is 2300+1600 = 3900 kg East (x) = 3900 * Vx = -18,101 North (y) = 3900*Vy = 14,098 so Vx = -4.64 m/s Vy = 3.61 m/s
*November 25, 2014*

**U.S. History**

I was not aware of a "league of friendship".
*November 24, 2014*

**physics (would mr. sue or mrs damen answer my ques**

Not unless you give us the heat of fusion of water and the specific heat of water and silver. mass silver * specific heat of silver * (107-T) = heat of fusion of water * mass of ice
*November 24, 2014*

**liberal arts**

whoops sorry, forgot that he works at night. 2 * 4 = 8 then out the next day, 5 days
*November 24, 2014*

**liberal arts**

two feet every 2 days until we get within five 2*4 = 8 in 8 days now the ninth day we go up to 8+5 = 13 so we are free after 9 days
*November 24, 2014*

**Physics**

you did not give me the frequency or anything.
*November 24, 2014*

**math problem (please help)**

2 w + 2 L = 70 so w+L = 5 and L = (35-w) 300 = w (35-w) w^2 -35 w + 300 = 0 (w-20)(w-15) = 0 w = 15 or 20 so w = 15 and L = 20
*November 24, 2014*

**physics**

10 log I1/I2 = 10 log (102/408) = 10 log .25 = -6.02 so 6 lower
*November 24, 2014*

**physics**

G M m/r^2 = m g = 50 G M /r^2 = g = 50/30
*November 24, 2014*

**physics**

a = F/m = (7-3) * 10^4 / (1.3*10^5)
*November 24, 2014*

**physics**

I2/I1 = R1^2/R2^2 = 5^2/(10^4)^2 = 25 * 10^-8 10 log (25*10^-8) = 10 [-8 + 1.4] = - 66 dB 103 - 66 = 37 dB still pretty loud
*November 24, 2014*

**Math I need help ASAP! I'm getting timed**

Which ratios form a proportion? 1. 4/12 , 6/8 2. 16/12 , 3/4* 3. 3/2 , 15/14 4. 10/16 , 5/8 10/16 = 5/8 Which ratio forms a proportion with 9/15? 1. 6/10 2. 16/21 3. 36/50 4. 45/70 9/15 = 3/5 which is 6/10 A textbook weighs 2.5 pounds. How many kilograms does the textbook ...
*November 24, 2014*

**physics**

1. zero is correct 2. yes, any force up from the floor has no moment arm 3. change in Pe = m g h = (1/2) m g L Ke = (1/2) m v^2 + (1/2) I w^2 I = (1/12) m L^2 v = (L/2)w so Ke = (1/2)m(L^2/4)w^2 + (1/2)(1/12)m L^2 w^2 = (m L^2 w^2) (1/8 + 1/24) = m L^2 w^2 (1/6) so (1/2) m g L...
*November 24, 2014*

**math calculus**

agree
*November 24, 2014*

**calculus**

s = (6t+3)^.5 ds/dt = .5 (6t+3)^-.5 (6) = 3 (6t+3)^-.5 d^2s/dt^2 = 3 [ -.5(6t+3)^-1.5 *6) = -9 /(6t+3)^1.5 if t = 1 -9 / 9^(3/2) -9/27 -1/3 yes D
*November 24, 2014*

**ratios and proportional relationships**

15/100 = 75/w so w = 7500/15
*November 24, 2014*

**trig**

1. cos x = 1/2 x = 60 or x = -60 which is 300 in degrees or x = pi/3 or x = 2pi-pi/3 = 5 pi/3 in radians
*November 24, 2014*

**physics**

period = T = 18.5/23 seconds speed = 168 centi meters/ 20.21 seconds distance = speed * time = (168/20.21)(18.5/23)
*November 24, 2014*

**Chemistry**

If it weighs any number of grams it has millions of atoms even if it is URANIUM!!!!! 6.02 * 10^23 molecules/mol Avagadro's constant 7 C = 84 g/mol 8 H = 8 g/mol so 92 g/mol (74.5/92) * 6*10^23 = 4.86 *10^23 MOLECULES 7 times that many C atoms 8 imes that many H atoms
*November 24, 2014*

**science**

CO2 has just as many O atoms as O2 so the same number of mols
*November 24, 2014*

**PLEASE HELP CHEMISTRY**

Ag = 108 g/mol N =14 g/mol O3 = 3*16 = 48 g/mol so AgNO3 = 170 g/mol of which 108 is silver (108/170)(85) = 54, close enough
*November 24, 2014*

**Calculus**

y = f(x) dy/dx = f'(x) = y' first derivative d^2y/dx^2 = f''(x) = y'' second derivative
*November 24, 2014*

**Algebra**

cost = 30,000 + 42.25 x so 64.95 x = 30,000 + 42.25 x profit = (64.95-421.25)x - 30,000 = 100,000
*November 24, 2014*

**Chemistry**

Hey, Li has ONE valence electron I think you mean Li2SO4 6.02 * 10^23 molecules/mol so we have 6.78/6.02 = 1.13 mols of Li2SO4 which mean 2.26 mols of Li+ ions then we have 1.13 mols of SO4-- ions so 2.26 + 1.13 = 3.39 mols of ions in all
*November 24, 2014*

**chemistry physics**

You are welcome
*November 24, 2014*

**chemistry physics**

You get back 40 (((miles / hr) meters) / second) = 17.8816 m2 / s2
*November 24, 2014*

**chemistry physics**

Use Google for those conversions type 40 miles/hr meters/second and click
*November 24, 2014*

**chemistry physics**

looks resonable
*November 24, 2014*

**chemistry physics**

I just sent you a link for these Doppler problems.
*November 24, 2014*

**Math Help!**

That is the way I would do it :)
*November 24, 2014*

**Math Help!**

or rather 100 x = 6 * 179,000 x = 6 * 1790 = 10,740
*November 24, 2014*

**Math Help!**

yes 100 x = 6 * 179,000 = 6 * 1790 = 10,740
*November 24, 2014*

**Math Help!**

I would write 6/100 = x /179,000
*November 24, 2014*

**Math Help!**

In real life I would not have done this as a proportion. I would have said .06 * 179,000 = 10,740
*November 24, 2014*

**Math Help!**

I would not have written it your way, but your arithmetic is strange and I can not see how you got the right answer. 107400/100 = 1074 not 10740 but 10740 is correct
*November 24, 2014*

**Math Help!**

6/100 = x /179,000 yes answer is 10,740 but you method is suspect
*November 24, 2014*

**Chemistry Physics**

yes, just did this a minute ago http://hyperphysics.phy-astr.gsu.edu/hbase/sound/dopp.html#c4
*November 24, 2014*

**math**

7 + x 2 + x 7+x = 2 (2+x) 7 + x = 4 + 2 x x = 3
*November 24, 2014*

**Math Help!**

.3 * 60 = 18
*November 24, 2014*

**math physics**

yes http://hyperphysics.phy-astr.gsu.edu/hbase/sound/dopp.html#c4
*November 24, 2014*

**calculus**

You do not really need calculus. It is a parabola, find the vertex y=(x^2)-6x+10 x^2 - 6 x = y - 10 x^2 - 6 x - 9 = y-19 (x-3)^2 = (y-19) vertex at (3 , 19)
*November 24, 2014*

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