Wednesday

August 20, 2014

August 20, 2014

Total # Posts: 17,938

**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...
*March 27, 2014*

**social study**

http://gloucester-ma.gov/index.aspx?nid=649
*March 27, 2014*

**social study**

here's one here: http://wgbhnews.org/post/wind-turbines-power-gloucester-city-buildings
*March 27, 2014*

**Calculus**

huh?
*March 27, 2014*

**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
*March 27, 2014*

**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
*March 27, 2014*

**Physics Help**

Pairs of forces probably refers to Newton's third law, for every force there is an equal and opposite force.
*March 27, 2014*

**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
*March 27, 2014*

**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
*March 27, 2014*

**Chemistry**

ml ranges from -L to +L If L = 0, ml = 0
*March 26, 2014*

**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
*March 26, 2014*

**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
*March 26, 2014*

**Alegbra**

You are welcome :)
*March 26, 2014*

**Alegbra**

Yes, right :)
*March 26, 2014*

**Alegbra**

LOL -1/3 = -0.33333333333333333
*March 26, 2014*

**Alegbra**

It would really help you if you sketched these points on a graph, or at least the x values on a number line.
*March 26, 2014*

**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
*March 26, 2014*

**Alegbra**

You are welcome.
*March 26, 2014*

**Alegbra**

Hailey to find something halfway in between, just take the average which is the sum divided by two
*March 26, 2014*

**Alegbra**

If you men the earlier question I gave you both x and y of the point. Y is 1/2
*March 26, 2014*

**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
*March 26, 2014*

**math**

(2/5) * 50 = 20 tigers (1/5) * 50 = 10 leopards sum = 30 so 50 - 30 = 20 lions
*March 26, 2014*

**Math**

yes
*March 26, 2014*

**Math**

3.3636... > 3.3333...
*March 26, 2014*

**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
*March 26, 2014*

**statistics**

18 + 24 = 42 first black sock = 24/42 second black sock = 23/41 product = 24/42 * 23/41 = .321
*March 26, 2014*

**3rd grade math missing info**

Need one more fact, like how much did they spend together or how much did Luis spend.
*March 26, 2014*

**Calculus**

dp/dt = v = 2 t at t = 2 v = 2*2 = 4
*March 26, 2014*

**Alegbra**

I gave you x and y y is 1/2
*March 26, 2014*

**Alegbra**

average x = (5-1)/2 = 2 average y = (-2+3)/2 = 1/2 so (2 , 1/2)
*March 26, 2014*

*******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 = ....
*March 26, 2014*

**Ms. Sue please help**

SORRY, DID NOT READ THAT PERPENDICULAR WORD.
*March 26, 2014*

**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
*March 26, 2014*

**Equations Help**

I decline to answer on the grounds that you can figure that out.
*March 26, 2014*

**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)
*March 26, 2014*

**American History**

None of them really. http://www.huffingtonpost.com/matthew-pearl/top-five-myths-about-edga_b_334742.html
*March 26, 2014*

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

You are welcome
*March 26, 2014*

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

1. I have no idea. 4. A) yes 5. B) yes 6. C) yes 8. C) yes
*March 26, 2014*

**math**

7.5 * 50
*March 26, 2014*

**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
*March 26, 2014*

**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
*March 26, 2014*

**Maths Missing the sequence**

You can not copy and paste here.
*March 26, 2014*

**American History**

http://millercenter.org/president/johnson/key-events Civil Rights Act
*March 26, 2014*

**Algebra inequality missing**

If you tried to copy and paste, that does not work here.
*March 26, 2014*

**Maths**

a = (2x+4) - (4x+1) = -2x + 3 and a = (x+3) - (2x+4) = -x - 1 so 2x-3 = x+1 x = 4
*March 26, 2014*

**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.
*March 26, 2014*

**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
*March 26, 2014*

**physics**

h = (1/2) g t^2
*March 26, 2014*

**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
*March 26, 2014*

**science**

H2O2(g)+2CO(g) ----> H2(g)+2CO2(g) so ?
*March 26, 2014*

**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
*March 26, 2014*

**geometry**

infinite number even if no curvy tops If it is rectangular then x^2 h = 28 h = 28/x^2
*March 26, 2014*

**phy113**

assuming 100 degree steam slope = (242 -22.8) /(100 -0) = 2.19 mm/degree so 22.8 + 2.19(20) = 66.6 mm
*March 26, 2014*

**Quick Math Question**

You are welcome.
*March 26, 2014*

**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]
*March 26, 2014*

**physics**

no motion in direction of force ----> no work done
*March 26, 2014*

**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
*March 25, 2014*

**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 ...
*March 25, 2014*

**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.
*March 25, 2014*

**ALGEBRA**

I did the two equations at the limits and said look between them
*March 25, 2014*

**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
*March 25, 2014*

**algebra**

By intervals he means BETWEEN the zeros of the two functions
*March 25, 2014*

**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
*March 25, 2014*

**algebra**

http://www.jiskha.com/display.cgi?id=1395791951#1395791951.1395793571
*March 25, 2014*

**algebra**

Look at my last reply to you
*March 25, 2014*

**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 ...
*March 25, 2014*

**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
*March 25, 2014*

**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
*March 25, 2014*

**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
*March 25, 2014*

**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
*March 25, 2014*

**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)
*March 25, 2014*

**Physics**

Been there, done that scroll down .
*March 25, 2014*

**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)
*March 25, 2014*

**physics**

tan Theta = 50/100 Theta = 26.6 degrees
*March 25, 2014*

**math**

1 kilogram = 1000 grams so we have 1000 + 600 = 1,600 grams or 1.6 kilograms
*March 25, 2014*

**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
*March 25, 2014*

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

http://www.jiskha.com/display.cgi?id=1360959210
*March 25, 2014*

**math**

If the state department of transportation says so, we are supposed to believe it.
*March 25, 2014*

**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 ...
*March 25, 2014*

**Algebra**

L = w+5 2 L + 2 w = 66 or L + w = 33 so w + 5 + w = 33 2 w = 28 w = 14 etc
*March 25, 2014*

**chemistry**

yes 1 Ba , 2 H , 2 O
*March 25, 2014*

**Oh, sorry**

I did not read carefully.
*March 25, 2014*

**chemistry**

Google it eg http://www.webqc.org/balance.php?reaction=BAO+%2B+H2O+%3D+BA%28OH%292
*March 25, 2014*

**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.
*March 25, 2014*

**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
*March 25, 2014*

**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)
*March 25, 2014*

**algebra**

point at (0,1) then right 1 and down 4
*March 25, 2014*

**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
*March 25, 2014*

**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
*March 25, 2014*

**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
*March 24, 2014*

**Physics( Explain and choose right answer)**

The tension is smallest at the top, if the speed is in fact enough to make the top without the tension going to zero. At top: Tension + m g = m v^2/R tension = m (v^2/R - g) if the centripetal acceleration is not greater than g, the rope goes slack.
*March 24, 2014*

**Physics( Explain and choose right answer)**

actually speed rather than velocity because directions are opposite.
*March 24, 2014*

**Physics( Explain and choose right answer)**

initial momentum = 0 so final momentum = 0 0 = 3*Vcat + 1.5*Vcardboard so Vcardboard = 3 Vcat/1.5 = 2 Vcat
*March 24, 2014*

**4th grade math**

(3/4)8 = 3 (2) = 6
*March 24, 2014*

**History 8th**

Yorktown, Virginia
*March 24, 2014*

**Treaty of Paris, quick question, thanks! ☺**

Britain had little choice. That is what it was all about.
*March 24, 2014*

**Math**

(24 b/ 10 s) (60 s/ min) (3 min) = 432 b
*March 24, 2014*

**math**

1.0/2 = 0.5
*March 24, 2014*

**Treaty of Paris, quick question, thanks! ☺**

Sign tied to the rock wall in front of my house says "We miss Bobby"
*March 24, 2014*

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