Saturday

August 2, 2014

August 2, 2014

Total # Posts: 17,591

**Dimensionless parameters**

By the way if gravity had been important (waves), we would have also found the Froude number v/sqrt(gL)

**Dimensionless parameters**

d/H had better be the same for model and experiment If viscosity were important then rho vL/mu, the dimensionless Reynolds number should be the same, but the problem statement says mu is not important so we are left with d/H and the ratio of force to other parameters which we ...

**CALCULUS problem**

int x^-3 dx = -.5 x^-2 + c at x = 3 = -.5/9 at x = 1 = -.5 so A = .5 - .5/9 = .5(8/9) = 4/9 B at x = h int = -.5/h^2 right half = -.5/9 +.5/h^2 left half = -.5 h^2 +.5 so -.5 h^2 + .5 = -5/9 +.5/h^2 1/h^2 = .5 + 5/9 = 4.5/9 + 5/9 = 9.5/9 = 19/18 int 1 to 3 of pi (x^-6)dx = -pi...

**who dare to give the answer!**

I not only do not dare, I do not have the slightest idea what you are talking about.

**Math**

I am not familiar with the notation but what happens is (x , y) --->(x , -y) so I would choose C.

**makes no sense**

Please check what you typed.

**typo**

same volume both times

**maths**

p = 2000 + 100 x - 6 x^2 if x = 25 p = 2000 + 2500 - 3750 p = 750 not a wise decision unless there is a typo

**math**

Well, let's hope we are right :)

**math**

surface area = 4 pi r^2 so dv/dt = 4 pi r^2 dr/dt dv/dt = 75 cm^3/s so dr/dt = 75/(4 pi r^2) when r = 5 dr/dt = 3/(4 pi) = .75/pi cm/s after 60 seconds volume = 75*60 = 4500 cm^3 (4/3)pi r^3 = 4500 pi r^3 = 3375 r = 15/pi^(1/3) r^2 = 225/pi^(2/3) 4 pi r^2 = 900 pi^(1/3) dr/dt ...

**social study**

http://gloucester-ma.gov/index.aspx?nid=649

**social study**

here's one here: http://wgbhnews.org/post/wind-turbines-power-gloucester-city-buildings

**Calculus**

huh?

**Calculus**

x = ln 243 y = ln 32 LET Z = e^((3x + 4y)/5) ln [z ]= (3x+4y)/5 ln z = (1/5)( 3 ln 243 + 4 ln 32) = ln (243^3/5 *32^4/5) = ln (27*16) = ln(432) if ln z = ln 432 then z = 432

**physics**

v = Vi -7.1 t 0 = 43 - 7.1 t t = 43/7.1 = 6.06 s average speed during stop = 7.1 /2 =3.55 m/s d = 3.55 * 6.06 = 21.5 m

**Physics Help**

Pairs of forces probably refers to Newton's third law, for every force there is an equal and opposite force.

**Physics Help**

Impulse is mass times change in velocity because Force * time = change of momentum = change of m v = m * change of v if m is constant

**physics**

potential energy of each at start = k q^2/r at large distance that energy is kinetic so (1/2)m v^2 = k q^2/r

**Chemistry**

ml ranges from -L to +L If L = 0, ml = 0

**Chemistry**

4 is out because with L = 0 you have no choice of ml = 1. wtih L = 0 ml = 0 and spin can be 1/2 or -1/2 ml = 1 is not allowed if L = 0

**Chemistry**

3) is out, spin is =/- 1/2 1) is out, negative L 2) is out , biggest L is n-1 or 2 4) is out, with L=0 you only have +/- 1/2 for spin, no ml - 1 5) looks possible 6) looks possible

**Alegbra**

You are welcome :)

**Alegbra**

Yes, right :)

**Alegbra**

LOL -1/3 = -0.33333333333333333

**Alegbra**

It would really help you if you sketched these points on a graph, or at least the x values on a number line.

**Alegbra**

from G to H x goes from 3 to -2 or -5 easier for me to go (1/3) of 5 from H to G so -2 + 5/3 which is -6/3 + 5/3 or x = -1/3

**Alegbra**

You are welcome.

**Alegbra**

Hailey to find something halfway in between, just take the average which is the sum divided by two

**Alegbra**

If you men the earlier question I gave you both x and y of the point. Y is 1/2

**Math**

prob that next one is above 75 = .6 prob that the one after that is independently .6 again so probability of both = .6*.6 = .36

**math**

(2/5) * 50 = 20 tigers (1/5) * 50 = 10 leopards sum = 30 so 50 - 30 = 20 lions

**Math**

yes

**Math**

3.3636... > 3.3333...

**math**

x = 38 + 5 t y = 30 + 7 t when does x = y? 38 + 5 t = 30 + 7 t 2 t = 8 t = 4 hours

**statistics**

18 + 24 = 42 first black sock = 24/42 second black sock = 23/41 product = 24/42 * 23/41 = .321

**3rd grade math missing info**

Need one more fact, like how much did they spend together or how much did Luis spend.

**Calculus**

dp/dt = v = 2 t at t = 2 v = 2*2 = 4

**Alegbra**

yes

**Alegbra**

I gave you x and y y is 1/2

**Alegbra**

average x = (5-1)/2 = 2 average y = (-2+3)/2 = 1/2 so (2 , 1/2)

*******Help Statistic**

ell, I will just do the problem a yes p(right) = .5, (1 -pright)=.5 b half of them, 5 10 trials p(k) = C(n,k) p^k (1-p)^(n-k) p(6)=C(10,6) .5^6 .5^4 =210*.015625*.0625 = .205 p(7) = 120*.5^7*.5^3 = .117 p(8) = 45*.5^8 *.5^2 = .044 p(9) = 10*.5^9*.5 = .0098 p(10) = 10*.5^10 = ....

**Ms. Sue please help**

SORRY, DID NOT READ THAT PERPENDICULAR WORD.

**Ms. Sue please help**

A (-8, -4) and B (1, -5) SLOPE = (-5 - -4)/ (1 - -8) = (-5+4)/(1+8) = -1/9 F(3,7) and G (-4, -5) SLOPE = (-5 -7)/(-4-3) = 12/7 H(-1, 0) and I (4, 6) SLOPE = (6-0)/(4 - -1) = 6/5 NOT PARALLEL AND NOT PERPENDICULAR y=4x-3 AND (2,3) 3 = 4(2) + b b = -5 SO Y = 4 X - 5

**Equations Help**

I decline to answer on the grounds that you can figure that out.

**Equations Help**

b^2-4ac = 4 + 20*12 positive so two real roots b^2-4ac = 324 -4(3)(27) = 324-324 = 0 so two identical real number roots (the graph just grazes the x axis)

**American History**

None of them really. http://www.huffingtonpost.com/matthew-pearl/top-five-myths-about-edga_b_334742.html

**Social studies check answers ***damon*****

You are welcome

**Social studies check answers ***damon*****

1. I have no idea. 4. A) yes 5. B) yes 6. C) yes 8. C) yes

**math**

7.5 * 50

**American History**

a is wrong b is true c wrong, started 1865 d geography is wrong or railroad is wrong :) http://railroad.lindahall.org/essays/brief-history.html

**Maths**

if you mean the sequence in your previous problem a = -5 -123 = 17 - 5n n = 28 or 28 terms before our first term which was 17

**Maths Missing the sequence**

You can not copy and paste here.

**American History**

http://millercenter.org/president/johnson/key-events Civil Rights Act

**Algebra inequality missing**

If you tried to copy and paste, that does not work here.

**Maths**

a = (2x+4) - (4x+1) = -2x + 3 and a = (x+3) - (2x+4) = -x - 1 so 2x-3 = x+1 x = 4

**Calculus**

I did one for you. Now you do this one. By the way you left the half life of carbon 14 or exponential decay function out of your statement of the problem making it impossible without looking that up.

**Calculus**

12 = 40 e^(-kt) .3 = e^-30 k ln .3 = -30 k -1.20 = -30 k k = .04013 so .5 = e^-.04013 t -.6931 = -.04013 t t = 17.3 years

**physics**

h = (1/2) g t^2

**Math**

1 mile (5280 ft/mile)(1 yard/3 ft) = 1760 yards so 1 square mile = (1760)^2 = 3,097,600 yd^2 3,097,600 yd^2 * 1 day/4840 yd^2 = 640 days 640 days * 1 year/365 days = 1.75 years

**science**

H2O2(g)+2CO(g) ----> H2(g)+2CO2(g) so ?

**Math**

2/12 or 1/6 cup leaks out so 11 5/6 are left 11 5/6 = 69/6 (69/6)/4 = 69/24 = 2 21/24 = 2 7/8 each

**geometry**

infinite number even if no curvy tops If it is rectangular then x^2 h = 28 h = 28/x^2

**phy113**

assuming 100 degree steam slope = (242 -22.8) /(100 -0) = 2.19 mm/degree so 22.8 + 2.19(20) = 66.6 mm

**Quick Math Question**

You are welcome.

**Quick Math Question**

3 ln x = ln x^3 ln x^3 + ln|x+1| = ln [x^3(x+1)] = ln [x^4 + x^3]

**physics**

no motion in direction of force ----> no work done

**physics!!!!!**

Ac = v^2/R at bottom T = tension in rope T = m g + m v^2/R 28 = 1.8(9.81) + 1.8 v^2/1.55 10.34 = 1.16 v^2 v = 2.98 m/s at top if T = 0 then g = v^2/R 9.81 = v^2/1.55 v = 3.9 m/s

**Rosaline have you got it ?**

If you are still stuck, look at the graphs Steve linked you to carefully and see three areas between the curves on the x axis. Those are values of x where your original function is between the limits. The last area on the right is not feasible because the width would be negati...

**ALGEBRA**

go back to where Steve is helping you as well and look at the graphs. Watch out though, the third region makes the box higher than half the width so will not work.

**ALGEBRA**

I did the two equations at the limits and said look between them

**ALGEBRA**

I set them equal to 1512 and then to 2176 THEN I subtracted 1512 from the first both sides AND I subtracted 2176 from the second both sides PLEASE calm down and think

**algebra**

By intervals he means BETWEEN the zeros of the two functions

**algebra**

the plate is only 25 cm wide so the big x interval will not work I got results in the middle of the first two intervals though

**algebra**

http://www.jiskha.com/display.cgi?id=1395791951#1395791951.1395793571

**algebra**

Look at my last reply to you

**math**

It is two functions and there are three regions where they cross the x axis Any x between the curves on the x axis should work. However the third region on the right has too big an x so the width will come out negative however when I tested in the middle of the first two regio...

**math**

Oh well 4 x^3 - 130 x^2 + 1000 x = 1512 is the same as 4 x^3 - 130 x^2 + 1000 x - 1512 = 0

**math**

ok, I tried x = 3 and it works now for x = 7 which is between those last roots 7(40-14)(25-14) = 7*26*11= 2002 so that region also works

**math**

then: http://www.solvemymath.com/online_math_calculator/algebra_combinatorics/polynomial_calculator/polynomial_roots.php I get 21.85, 2 and 8.65 and 22.4 4 and 6.06 well x between 2 and 4 works 21 and 22 are too big you might try between 8.65 and 6.06

**math**

use http://www.webmath.com/_answer.php to get 4 x^3 - 130 x^2 + 1000 x or just FOIL the last two and multiply by x Then 4 x^3 - 130 x^2 + 1000 x -1512 = 0 and 4 x^3 - 130 x^2 + 1000 x - 2176 = 0

**Phys**

10 = x * 1.6*10^-19 10 * 10^19 = 1.6 x x = 6.25 * 10^19 well, quite a few, but less than a mol (6*10^23)

**Physics**

Been there, done that scroll down .

**Physics**

well if you started out with everything neutral and one got negative then the other got positive (the rod stole electrons from the wool, becoming negative. That left the wool with an excess of protons, becoming positive)

**physics**

tan Theta = 50/100 Theta = 26.6 degrees

**math**

1 kilogram = 1000 grams so we have 1000 + 600 = 1,600 grams or 1.6 kilograms

**math**

the hour hand moves from 6 to 7 in one hour It will not be half way between until 6:30 So it is still closer to 6

**Oh - I bet this is the problem**

http://www.jiskha.com/display.cgi?id=1360959210

**math**

If the state department of transportation says so, we are supposed to believe it.

**Trig Identities**

If hypotenuse is 1 opposite = sin T adjacent = cos T 1^2 = (sin T) ^2 + (cos T)^2 as we know and sin^2 T = 1 - cos^2 T sin T = +/- sqrt (1-cos^2 T) well, that is not much of an identity if the sign is arbitrary. BUT if we use the negative root then we know that cos^2 T is alwa...

**Algebra**

L = w+5 2 L + 2 w = 66 or L + w = 33 so w + 5 + w = 33 2 w = 28 w = 14 etc

**chemistry**

yes 1 Ba , 2 H , 2 O

**Oh, sorry**

I did not read carefully.

**chemistry**

Google it eg http://www.webqc.org/balance.php?reaction=BAO+%2B+H2O+%3D+BA%28OH%292

**physics 1**

Hey, wait a minute. If there were no gravity it would have taken less time to stop. The total force up including gravity = change of momentum so there is no change to the force in part b due to gravity.

**physics 1**

force = rate of change of momentum = 88.1*3.53 / .00356 = 87,358 N = 88.1*3.53/.199 = 1,563 N with gravity add 88.1*9.81 = 864 N

**Geometry**

x = (-2 + -3) /2 = -5/2 = -2.5 y = (1+2)/2 = 1.5 so ( -2.5 , 1.5 ) (which you could see on a quick sketch)

**algebra**

point at (0,1) then right 1 and down 4

**Physics**

gain in energy = m g h = 1.2 * 9.81 * 34.2 = 403 Joules 403 = (1/2) m v^2 + (1/2)I omega^2 I = m r^2 = 1.2 (.09) = .108 omega = v/r = v/0.3 so 403 = (1/2)(1.2)(v^2) +(1/2)(.108)(v^2)/.09 403 = v^2 ( .6 + .583) v = 18.5 m/s I agree with you

**physics**

initial momentum = 1000 m final momentum = 910(m-1,000) + 10^7 90 m = .091*10^7 + 10^7 = 1.091*10^7 m = 121,222 kg

**algebra**

(x-0)(x-7)(x+4)(x-5) = 0 (x^2 -7x)(x^2-x -20) = 0 x^2(x^2-x-20)-7x(x^2-x -20) = x^4 -x^3 - 20 x^2 - 7x^3 + 7x^2 + 140 x = x^4 - 8 x^3 - 13 x^2 + 140 x

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