Sunday

September 21, 2014

September 21, 2014

Total # Posts: 18,583

**typo**

plus or minus 60 x
*June 13, 2014*

**maths**

natural log (base is e) is usually written ln(x) ln (e^x) = x ln e but ln e = 1 so ln (e^x) = x * 1 = 1 argument is somewhat circular but I do not know what else to say.
*June 13, 2014*

**algebrahave i done this right**

You are welcome :)
*June 13, 2014*

**algebrahave i done this right**

mean = 1770/27 = 65.56 mode is clearly 70 if there are ten of them median, there are 10 below 70 and 4 above 70 so the median is in your 70 group, yes the range is from 40 to 90 so yes 50
*June 13, 2014*

**algebrahave i done this right**

I do not understand. is your data set 2 90 s 5 80 s 10 70 s etc? if so I count 27 data points not 25
*June 13, 2014*

**typo?**

the height is 5 meters? do you mean the length is maybe 50 meters? anyway perimeter = 2*L + 2*W area = L * W
*June 13, 2014*

**PHYSICS**

centripetal acceleration Ac = R omega^2 R = earth radius at equator but R = 0 at poles rotation of earth tries to throw you off into space but gravity holds you on earth. g = 9.81 - R omega^2
*June 13, 2014*

**Algebra please can you ck my work**

check my earlier answers things are getting worse except for the 152 ---512 typo
*June 13, 2014*

**algebra/please can you ck my answers**

log base ten of 16.9 = 1.23 log2 (512 not 152) = 9 because base^log x = x 2^9 = 512 log 1 = 0 for any base at all because any base^0 = 1 log base 10 = log10(.046) = -1.34 that is NEGATIVE 1.34
*June 13, 2014*

**PHYSICS**

LOL, try it with anything on your desk, gently ! it will experience BOTH angular acceleration (spin) and linear acceleration.
*June 13, 2014*

**Algebra**

You are welcome.
*June 13, 2014*

**Algebra**

40/1.6 = n/5 so n = 200/1.6 = b) 150 * 1.6/40 =
*June 13, 2014*

**USA Colonists History**

http://www.mainememory.net/sitebuilder/site/283/page/546/display
*June 13, 2014*

**USA Colonists History**

... or fresh water :)
*June 13, 2014*

**USA Colonists History**

The English had a serious problem finding tall white pines for masts in Europe, particularly when they were having trouble with countries around the Baltic Sea. I do not do land, sorry.
*June 13, 2014*

**USA Colonists History**

catch cod, sell it in the West Indies and Europe catch beavers, sell fur in Europe
*June 13, 2014*

**Physics**

1 * 605 * 10^-9 * .85 / 5.4 *10^3 = 95 * 10^-6 m = .095 mm
*June 13, 2014*

**Physics**

yes, up means higher frequency
*June 13, 2014*

**Physics**

yes
*June 13, 2014*

**algebra**

1 and 2 that is 2/6 or 1/3 450/3 = 150
*June 13, 2014*

**Physics**

wait a minute, add the weight of the ball!. 10 + 10*9.81 = 108 N
*June 13, 2014*

**Physics**

You are welcome.
*June 13, 2014*

**Physics**

Force * time = impulse = change in momentum T (10) = 10 * 10 T = 10 N which by the way is about the weight of the ball on earth. I think it would take longer.
*June 13, 2014*

**physics**

distance = speed * time with no force in horizontal direction 65 = 14 t t = 4.64 seconds in the air In the vertical direction it simply falls a distance h h = (1/2) g t^2 = 4.9 (4.64^2) h = 106 m
*June 13, 2014*

**Physics**

80 cal = 335 joules so Lf = 335 Joules / .001 kg - 335,000 Joules/kg potential energy = m g h m g h = m (335,000) 9.81 h = 335,000 h = 34,149 meters
*June 13, 2014*

**PHYSICS**

2 pi radians every 60 seconds 2 pi/60 = pi/30
*June 13, 2014*

**Physics**

call side of square = 1 look at components along diagonal 2(1.1 *1.1 /1^2)cos 45 = 1.1 q/(sqrt2)^2 cos 45 = 1/sqrt 2 2(1.1) = q/sqrt 2 q = 2.2 sqrt 2
*June 13, 2014*

**Physics**

F = m a F = E q same for both where q = electron charge, + for proton, - for electron m = mass electron for electron m = mass proton for proton
*June 13, 2014*

**Science**

Something you do to get something going. https://www.google.com/search?q=stimulus+definition&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=sb
*June 12, 2014*

**Math**

pi d^2/4 h (3.14 * 7.4*7.4 * 2.4 ) / 4
*June 12, 2014*

**MATH**

integral of e^(Lx)dx = (1/L) e^(Lx) + c
*June 12, 2014*

**Physics**

F = m a = -kx if x = A cos w t v = dx/dt = -Aw sin w t a = d^2x/dt^2 = -A w^2 cos w t = -w^2 x so -m w^2 x = -k x w^2 = k/m w^2 = 210/3 = 70 w = sqrt(70) = 8.37 when |x| = .23 , |v| = .72 .23 = A cos 8.37 t .72 = -A (8.37) sin 8.37 t so cos 8.37 t = .23/A sin 8.37 t = .086/A ...
*June 12, 2014*

**Physics**

North south problem 7.5 Vn = 4.5 (8.5 cos 30) -7.5(6.5 sin 20) East west problem 7.5 Ve = 4.5(8.5 sin 30) +7.5(6.5 cos 20)
*June 12, 2014*

**math equation**

1/3 + 1/4 = 4/12 + 3/12 = 7/12 right 12/12 - 7/12 = 5/12 right he has 5/12 left so 5/12 of salary = 400 multiply both sides by 12/5, the inverse 60/60 of salary = (12/5) * 400 = 12 * 80 = 960
*June 12, 2014*

**physics**

F = k x 10.5 = k (.72 k = 10.5 N/.72 m
*June 12, 2014*

**Science(electric circuits)**

Maybe the total current is the sum of the currents through the individual paths.
*June 12, 2014*

**Physics**

1/Req = 1/1 + 1/2 + 1/4 1/Req = 4/4 + 2/4 + 1/4 = 7/4 so Req = 4/7 The voltage is the same across all elements in parallel i for the 4 ohm = 6/4 = 1.5 amps P = i V or i^2 R = 1.5 * 6 or 2.25 * 4 = 9 watts
*June 12, 2014*

**Physics**

voltage across resistor = i R = 1.5*5 = 7.5 Volts voltage loss to internal resistance = 1.5 * .15 = .225 volts total voltage = 7.5 + .225 = 7.725 Volts
*June 12, 2014*

**physics**

.2 kw * 10 = 2 kw hr per day times 365 = 730 kw hr per year times .15 dollar/kw hr = $109.50 per year = $110 rounded to nearest dollar
*June 12, 2014*

**Science(electric circuits)**

If elements are in parallel, each sees the same voltage and the current is split up between them.
*June 12, 2014*

**physics**

100 * (.4/.05) = 800 N arms 0.4 meters long? That is one big nut cracker.
*June 12, 2014*

**physics**

F * 10 = 600 * 4 F = 600 * .4 = 240 N if you tried to lift at the other end F2* 10 = 600 * 6 F2 = 360 N
*June 12, 2014*

**physics**

http://www.jiskha.com/display.cgi?id=1402590278
*June 12, 2014*

**Science(electric circuits)**

voltages across individual elementsd add in a series circuit.
*June 12, 2014*

**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.
*June 12, 2014*

**Science(electric circuits)**

If devices are wired in series, the same current goes through each of them.
*June 12, 2014*

**science (help)**

water, fresh and salt.
*June 12, 2014*

**Algebra**

clark + clark + 5 = 33 2 clarks = 28 clark = 14 so shelly = 19
*June 12, 2014*

**Math**

6x,xx5 so 11 + 3 x = 23 3 x = 12 x = 4 64,445
*June 12, 2014*

**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
*June 12, 2014*

**Physics**

no idea, depends on coef of friction between road and man's shoes.
*June 12, 2014*

**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
*June 12, 2014*

**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
*June 12, 2014*

**Introductory Algebra**

Ah, what was that exchange rate ?
*June 11, 2014*

**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
*June 11, 2014*

**math**

infinity
*June 11, 2014*

**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))
*June 11, 2014*

**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
*June 11, 2014*

**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.
*June 11, 2014*

**Math**

Does your symbol mean greater than or equal to? If so: y - 6 >/= 12 add 6 to both sides y >/= 18
*June 11, 2014*

**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) ]
*June 11, 2014*

**HISTORY**

Well, we agree about Atlanta to the sea :)
*June 11, 2014*

**HISTORY**

12. Check your MAP !
*June 11, 2014*

**HISTORY**

Lincoln put off the proclamation until the Union won a battle, Antietam.
*June 11, 2014*

**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.
*June 11, 2014*

**HISTORY**

( I was born in Maryland :)
*June 11, 2014*

**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
*June 11, 2014*

**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 ....
*June 11, 2014*

**Physics**

yes (1/2) m v^2 = m g h so h = (1/2) v^2/g
*June 11, 2014*

**math (check answer plz)**

permutations of 8 taken in groups of 3 = 8!/(8-3)! = 8!/5! = 8*7*6 = 336 yes
*June 11, 2014*

**algebra**

n * 1.35 = 1600 + .41 n + 3700 .94 n = 5300
*June 11, 2014*

**math *check* (PERMUTATION)**

3 * 2 * 1 = 6
*June 11, 2014*

**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 ------------------------ ...
*June 11, 2014*

**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
*June 11, 2014*

**physics**

0 = 14.1 - 3.2 t as Janet told you below.
*June 11, 2014*

**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 ...
*June 10, 2014*

**math**

http://www.jiskha.com/display.cgi?id=1402442232
*June 10, 2014*

**math**

I just did that
*June 10, 2014*

**Macroeconomic**

I doubt it.
*June 10, 2014*

**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 ...
*June 10, 2014*

**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
*June 10, 2014*

**math (please check answer)**

You are welcome.
*June 10, 2014*

**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
*June 10, 2014*

**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
*June 10, 2014*

**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
*June 10, 2014*

**Physics**

You are welcome.
*June 10, 2014*

**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
*June 10, 2014*

**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
*June 10, 2014*

**math**

dp/dt = p/8 dp/p = .125 dt ln p = .125 t + c p = Po e^.125 t
*June 10, 2014*

**math**

1.08^10 = 2.16 2.16 * 10,000 = 21,589.25
*June 10, 2014*

**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, .....
*June 10, 2014*

**Math**

You are welcome.
*June 10, 2014*

**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
*June 10, 2014*

**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
*June 10, 2014*

**Physics**

Seems to me they better repel each other so I agree with you.
*June 10, 2014*

**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.
*June 10, 2014*

**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...
*June 10, 2014*

**Physics**

I agree with 1/2
*June 10, 2014*

**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
*June 10, 2014*

**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.
*June 10, 2014*

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