Saturday

August 2, 2014

August 2, 2014

Total # Posts: 17,591

**physics**

http://www.jiskha.com/display.cgi?id=1402590278

**Science(electric circuits)**

voltages across individual elementsd add in a series circuit.

**Science(electric circuits)**

If you take one element out of a series circuit, no current can flow and all elements lose power. Remember the old Christmas tree lights that were wired in series? If one went out, they all went out.

**Science(electric circuits)**

If devices are wired in series, the same current goes through each of them.

**science (help)**

water, fresh and salt.

**Algebra**

clark + clark + 5 = 33 2 clarks = 28 clark = 14 so shelly = 19

**Math**

6x,xx5 so 11 + 3 x = 23 3 x = 12 x = 4 64,445

**Physics**

south 7-3 = 4 east 7-4 = 3 d = sqrt (9+16) = 5km tan theta = 3/4 where theta is angle east of south theta = 36.9 deg east of south or 180 -36.9 = 143.1 on your compass clockwise from north

**Physics**

no idea, depends on coef of friction between road and man's shoes.

**physics**

Take moments about foot of ladder of length L 200 (L/2) sin 30 = F L sin 60 50 = F sin 60 F = 57.7 N

**Math**

area of layer = pi D^2/4 = 3.14 (49/4) = 38.465 in^2 8 layers = 307.72 in^2 divide by 55 5.6 batches so make 6

**Introductory Algebra**

Ah, what was that exchange rate ?

**algebra**

3 pounds of tin = 3(c+2) dollars 7 pounds of copper = 7 c dollars 10 pounds of bronze = 38.50 dollars so 7 c + 3 c + 6 = 38.5 c = 3.25 dollars per pound for copper so c+2 = 5.25 dollars per pound for tin

**math**

infinity

**Math help!**

let z = ln(5x) d/dx tan z = sec^2 z dz/dx but dz/dx = d/dx ln(5x) = (1/5x)5 = 1/x so (1/x)sec^2(ln(5x))

**Math help!**

I have a hunch you mean: (x^4+x^2+1)/(x^2+1) (bottom d top - top d bottom)/bottom squared [ (x^2+1)(4x^3+2x) -(x^4+x^2+1)(2x)]/(x^2+1)^2 [4x^5+6x^3+2x-2x^5+2x^3+2x]/(x^4+2x^2+1) [2x^5+8x^3+4x]/(x^4+2x^2+1

**Math**

You are welcome :) By the way, the only tricky thing on this general subject is that if you multiply (or of course divide) both sides by a negative number, reverse the direction of the arrow.

**Math**

Does your symbol mean greater than or equal to? If so: y - 6 >/= 12 add 6 to both sides y >/= 18

**math please help!**

d/dx [e^-(3x) ] [ sin (4 x) ] = [e^-(3x) ] d/dx [ sin (4 x) ] + [ sin (4 x) ] d/dx [e^-(3x) ] = [e^-(3x) ][4 cos (4x) ] + [ sin (4 x) ][ -3 e^-(3x) ] = e^-(3x)[ 4 cos (4x) -3 sin (4x) ]

**HISTORY**

Well, we agree about Atlanta to the sea :)

**HISTORY**

12. Check your MAP !

**HISTORY**

Lincoln put off the proclamation until the Union won a battle, Antietam.

**HISTORY**

9. agree 10. The border states mostly allowed slavery. Therefore there were by definition differences of opinion on the subject in the Union camp.

**HISTORY**

( I was born in Maryland :)

**HISTORY**

NO !!!!!!!!!!!!! Virginia was a free state that surrounded Washington, D.C., on the west and south. *** NO !!!!!!!!!!!!!!!!!!!!!!, a million times NO !!!! and MARYLAND WAS a SLAVE STATE that stayed in the union

**physics**

Do the vertical problem first Vi = initial speed up then v = Vi - g t at top, v = 0 0 = Vi - g t Vi = g t t = Vi/g h = 0 + Vi t - .5 g t^2 14 = Vi^2/g - .5 Vi^2/g 28 g = Vi^2 Vi = sqrt (28 g) Vi = 16.6 m/s Vi = v sin theta 16.6 = 24 sin theta so ....

**Physics**

yes (1/2) m v^2 = m g h so h = (1/2) v^2/g

**math (check answer plz)**

permutations of 8 taken in groups of 3 = 8!/(8-3)! = 8!/5! = 8*7*6 = 336 yes

**algebra**

n * 1.35 = 1600 + .41 n + 3700 .94 n = 5300

**math *check* (PERMUTATION)**

3 * 2 * 1 = 6

**physics**

72/3.6 = 20 meters/second (helpful to remember 1000 meters /3600 seconds = 1/3.6) 0 = 20 + a t t = -20/a x = Xi + Vi t + (1/2) a t^2 200 = 0 + 20 t + .5 a t^2 200 = 0 -400/a + .5 a (400/a^2) 200 a = -400 + 200 a = -1 so d, retardation of 1 m/s^2 ------------------------ altern...

**physics**

d/2 = 30 t1 so t1 = d/60 d/2 = 50 t2 so t2 = d/100 t = t1 + t2 d = v (t1+t2) = v (d/60 + d/100) 100 = v ( 5/3 + 3/3) = (8/3) v v = 300/8 = 37.5 km/hr

**physics**

0 = 14.1 - 3.2 t as Janet told you below.

**Math**

probability of what? one one and the ten or two ones or what? I guess I will assume you mean what is the probability of getting ten plus one first draw, probability of ten = 1/5 if you missed, you now have three ones and a ten probability of ten = 1/4 so the total probability ...

**math**

http://www.jiskha.com/display.cgi?id=1402442232

**math**

I just did that

**Macroeconomic**

I doubt it.

**math (check answer plz)**

37 marbles? first draw (red) 6/37 second time (independent because you replaced the marble and still have 37 blue 8/37 so 6/37 * 8/37 = 48/1369 You multiply to get probability of two independent events both happening, you add if two things satisfy your condition such as if the...

**Math- urgent**

You do not. Those are functions of an ANGLE, not a triangle They are defined in a right triangle. If A is one of the two angles that is not 90 degrees then sin A = opposite side/hypotenuse cos A = adjacent side / hypotenuse tan A = sin A/cos A = opposite/adjacent

**math (please check answer)**

You are welcome.

**math (please check answer)**

probability of failure = 147/156 it has to be one or the other so 1 - 147/156 = 9/156 = 3/52 agree

**math**

a ar ar^2 ar^3 sum of first 4 = a (1-r^4)/(1-r) = 32.5 a r^3 = 3375 a r^3 = 3375 r = 15 a ( 1-r^2)(1+r^2) /(1-r) = 32.5 a (1+r)(1+r^2) = 32.5 a (16)(226) = 32.5 a = .0089878 about 1 cent :) ar = .1348 ar^2 =2.02 ar^3 = 30.33 about 30 dollars

**math**

alcohol removed = 1/10 liter first time = 1/10 (.9) liter second time = 1/10 (.9)(.9) third time .... =1/10 (.9)^6 seventh time so amount removed = .1 + .1*.9^1 +....1*.9^6 seven terms a = .1 sum removed = .1 (1-.9^7)/.1 = .478 so amount remaining = 1-.478 = .522

**Physics**

You are welcome.

**Physics**

110 km/hr = 110,000 m/3600 s = 30.6 m/s m g h = (1/2) m v^2 9.81 h = .5 (30.6)^2 h = 47.7 meters (b) loss of energy = m g (47.7-22) = 750(9.81)(25.7) = 189,000 Joules lost (c) work done = force in direction of motion * distance moved 189,000 = F (22/sin2.5) F = 375 N

**Math**

distance = speed * time 3.54 * 10^7 = 3*10^8 t t = 3.54/3 * 10^-1 t = 3.54 / 30 = 0.118 seconds

**math**

dp/dt = p/8 dp/p = .125 dt ln p = .125 t + c p = Po e^.125 t

**math**

1.08^10 = 2.16 2.16 * 10,000 = 21,589.25

**math**

a ar ar^2 ar^2 - a = 25 or a (r^2-1) = 25 ar^2 - ar = 15 or ar(r-1) = 15 [25/(r^2-1) ] r (r-1) = 15 r (r-1) /[ (r+1)(r-1) ] = 15/25 = 3/5 r/(r+1) = 3/5 5 r = 3 r + 3 2 r = 3 r = 3/2 = 1.5 then a r^2 - a = 25 1.25 a = 25 a = 20 so 20, 30, 45, .....

**Math**

You are welcome.

**Math**

2 = e^35 k ln 2 = 35 k k = .0198 so a = 1400 e^.0198*3*60 a = 1400 e^3.565 a = 49,475.2

**Physics**

area of loop = .02^2 = .0004 m^2 dB/dt = .044/.1 = .44 emf = A dB/dt = .0004 *.44 = 1.76 * 10^-4 = .00018 V

**Physics**

Seems to me they better repel each other so I agree with you.

**math (cant figure it out)**

11 numbers, 6 of which are even if you count 0 as even (there are evidently 10 spaces between numbers but 11 numbers) so 6/11 but the question is poorly worded.

**My Final Algebra 1 Question**

a. x must be greater than 0 (undefined for x = 0) so x = 0 is not in the domain (infinite number of teachers) y, must be greater than 2 so range is 2 to very large (for small cost per teacher.) If x is a dollar per teacher, then y = 202 which seems a reasonable upper limit. b....

**Physics**

I agree with 1/2

**math**

(a+b)/2 = 9 so a+b = 18 sqrt ( a b) = 3 sqrt 5 so a b = 9*5 = 45 well so b = 45/a and a + 45/a = 18 or a^2 - 18 a + 45 = 0 ( a-15)(a-3) = 0 a = 15 or 3 so one of them is 3 and one of them is 15

**HISTORY**

Lincoln issued the proclamation under his powers as commander in chief of the US military ass an act of war. He had no authority to remove property from people with whom we were not at war.

**math**

arithmetic mean = (10+40)/2 geometric mean = sqrt (10*40) = 20

**HISTORY**

From Wikipedia: In the mid and late 1840s, immigrants from Ireland and Germany streamed into the city, swelling the population of Philadelphia and its suburbs.[52] In Philadelphia, as the rich moved west of 7th Street, the poor moved into the upper class' former homes, whi...

**math**

value = 1540 *(1/2)^(n/4) when n = 0, years, cost = 1540 for person 1 when n = 4 years, cost = 1540/2 for person 2 when n = 8, years, cost = 1540/4 for person 3 etc

**Maths**

Since it asks for depth wrt average, we do not need the 4 m average but only how much it departs from average at t = 0, d = -2 (low tide, 2 feet below average) d = -2 cos 2 pi t/T since T = 12 hours is given d = -2 cos (pi t/6)

**Algebra 1--Please, help me!**

(2x-20)(x+1) for example would be 2 x^2 - 18 x - 20 (2 x - 10)(x + 2) would be 2 x^2 - 6 x - 20 so 18 or 6 would work

**calculus**

(x+3)^2 = p (y-q) g = x + 7 when g = 0, x = A 0 = A + 7 A = -7 so A is 4 to the left of -3 therefore B is 4 to the right of -3 or at B = +1 so g = 7 at x = 0 so C = 7 A = (-7,0) B = (1,0) C = (0,7)

**Algebra 1-- Please, check my answers!**

As far as I know, yes

**Algebra 1-- Please, check my answers!**

Now wait a minute. Somewhere in your text book it says that if the denominator of a fraction is zero, that spot must be excluded from the domain of the function since the answer is undefined. Try dividing some number by zero on your calculator. Answer is "c". I had n...

**Algebra 1-- Please, check my answers!**

5. Which if the following is a true statement about the function y = 1/x? a. The domain is all real numbers. b. The range is all real numbers. c. The domain is all real numbers except 0. d. The range is all real numbers except 1. A: a? ============================= No, undefin...

**math**

Ah, two of us posted answers above.

**math**

change percent to decimal fraction by dividing by 100 so we mean .25 * 250 off 62.50 off 250 - 62.50 = $ 187.50 alternatively 100% - 25% = 75 % 75/100 = .75 .75 * 250 = $ 187.50 againg

**Algebra 1--Please, check my answer!**

When x = 6 (x-6) = 0 so y = 0 when x = 6 That is when it hits the x axis

**Algebra 1--Please, check my answer!**

If x = 6, bang if x = 6 bang so at ONE point x = 6 which is the vertex of the parabola. It just grazes the x axis and both roots are right there.

**Algebra II**

smallest = s biggest = b medium = m b = s + 90 m = s + 30 s + m + b = 180 s + s + 30 + s + 90 = 180 3 s = 60 etc.....

**Calculus**

yes

**Calculus**

See Baggins, Bilbo, "There and Back Again".

**Calculus**

Your velocity is zero at t = 3 !!!!! right in the middle of your range. It reversed direction midstream You calulated displacement (where it moved to which was nowhere) instead of how far it went (distance moved) do t = 0 to t = 3 then t = 3 to t = 6 add the ABSOLUTE VALUES

**physics**

How much energy should it have? m g h = 1.6 * 9.81 * 2.9 How much does it have? (1/2) m v^2 = (1/2) * 1.6 * (2.8)^2 so subtract

**math study guide**

1. no idea, do not have data 2. I get 8/20 = .40 3. again no data but in theory 3/4 4. 15/100 = 3/20 5. 20/100 = x/50 ??? Hey, are you just guessing or what?

**Science**

You are welcome.

**Science**

a) yes b) yes c) yes d) yes, traveling wave, air particles moving

**Math**

19 marbles p(first is purple) = 2/19 now 18 marbles, what is p(yellow) first p(yellow) = 5/18 so p(NOT yellow) = 13/18 p purple then not yellow) = 2/19 * 13/18

**Math**

p(not 5) = 5/6 then p(green) = 1/6 so 5/6 * 1/6 = 5/36

**Math**

Permutations of 7 items taken 3 at a time. The order matters so it is permutations, not combinations. Look at "ordered subsets" in the link: http://dwb4.unl.edu/Chem/CHEM869N/CHEM869NMats/Permutations.html 7! / (7-3)! = 7!/4! = 7*6*5 = 210

**Math**

There are four possible results A. Mike and Dave both miss B. Mike hit, Dave miss C. Dave hit, Mike miss D. both hit p mike hits = .6 so misses = .4 p dave hits = .3 so misses = .7 So p(A) = .4 * .7 p(B) = .6 * .7 p(C) = .3 * .4 p(D) = .6 * .3 We want p(A) + p(D) = .28 + .18 =...

**Math**

say 8/64 are red then probability of two red is 8/64 * 7/63 = 1/8 * 7/63 the next one is yellow, again same answer but now twice the probability so in the end 8 * 1/8 * 7/63 = 7/63

**Science**

or yes, yes :)

**Science**

35 * g = weight weight * distance raised = work in which is exactly the increase in potential energy

**Algebra ll**

You are welcome.

**Algebra ll**

yes

**Algebra ll**

(x - a)^2 + (y-b)^2 = r^2 for circle of radius r and center at (a,b)

**Math**

This is more fun every hour! Four ways now :)

**Math**

LOL !!!

**Math**

sketch a graph first If it goes through (0,4) and (2,4) I suspect that the center is on the line x = 1 (x-1)^2 + (y-b)^2 = r^2 when x = 0, y = 4 1 + (4-b)^2 = r^2 when x = 2, y = 4 1 + (4-b)^2 = r^2 again of course when x = -5, y = 0 36 + b^2 = r^2 so 1 +(4-b)^2 = b^2+36 1 + 1...

**Science**

8.b yes 9.c Huh? 21/21 = 1 10.a I do not think so. She, not the wheelbarrow, supplied the work. If it weighed 35 N and she lifted it 2.5 meters, then D would be correct. The problem is poorly written. It is not clear if the force is in the direction of motion.

**physics**

PE = - G m Me/R where G = 6.67 * 10^-11 Look at change in potential energy at R = 6.38*10^6 and at 6.38*10^6 + .120 *10^6 meters I bet it would not be far off to use m g h where g = 9.81 m/s^2 :) because 120 km is not far compared to Rearth

**calc**

draw a sketch If the interval means from x = -1 to x = +2, then it is also from y = 2 to y = 8 As I read it then this base is a triangle with corners at (-1,8) (2,2) and (-1,2) The volume of the figure would then be 2 times the area of the base Area of base = (1/2) (3)(6) = 9 ...

**pre calc**

(x+5)^2 = 4 (y + 1/2) vertex at (-5, -1/2) so for the left half x is always less than (to the left of) -5 an y is above -1/2 I do not know what else to say

**physics**

F = m g = G M m /r^2 so g = G M/R^2 double m, double g double R , divide by 4 so 15.5 / 2

**Chemistry**

In a liter you have .1 mol of HCl .1 * (35.5 + 1) = 3.65 grams/liter so in half a liter you have 1.825 grams of HCl

**Math**

2(117) - 1 is not 2001

**Math**

1, 3 , 5 , 7 , 9 ....... first is 1 = 2 - 1 second is 3 = 4 - 1 third is 5 = 6 - 1 number (n) = 2 n - 1 number (117) = 2(117) - 1

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