Wednesday

February 22, 2017
Total # Posts: 29,377

**math help asap**

Oh come on 15/10 = ? 24/16 = ? 30/20 = ?

*February 22, 2017*

**Educational Technology**

I am using library, school and other computers around town being very busy with local political issues. I google in to answer a question once in a while but usually do not remember to write my name in above.

*February 22, 2017*

**Hey, we did the one with the copies**

Your turn.

*February 21, 2017*

**Algebra**

machine 1 does n copies/170 min so n/170 copies/min machine 2 does n/119 copies/min so n = (n/170 + n/119) t 1/t = 1/170+1/119 = .014286 so t = 70 min

*February 21, 2017*

**math**

0 = -32 t + 28 so t = 28/32 google projectile motion in English units (acceleration of gravity = -32 ft/second^2)

*February 21, 2017*

**Math**

LOL, anywhere else !

*February 21, 2017*

**Algebra**

n and n+32 1/n + 5/(n+32) = 1/6 multiply all terms by 6n(n+32) 6(n+32) + 5(6n) = n(n+32) 6n + 192 + 30 n = n^2 + 32 n n^2 - 4n - 192 = 0 (n-16)(n+12) = 0 n = 16 n+32 = 48 ================ ================ check 1/16 + 5/48 = 1/6 ??? 3/48 + 5/48 8/48 1/6 sure enough

*February 21, 2017*

**math**

ratio is 1/2 so one of these: 8 4 6 3 4 2 2 1 difference is 2 so 42

*February 20, 2017*

**physics**

365.25*24 = h, number of hours distance = 2 pi r = 6.28* 1.5*10^8 km speed = distance/hours

*February 20, 2017*

**suggestion**

Maybe point (a,b,c) line like z = m x + n y + k find vector along line find vector from point to random spot on line do cross product, show independent of spot chosen on line. That cross product is perpendicular to the plane containing the two lines

*February 20, 2017*

**geomatry**

You are welcome :)

*February 20, 2017*

**Neil**

not area, perimeter

*February 20, 2017*

**geomatry**

sides a, b c perimeter = a+b+c perimeter 4 a + 4 b + 4 c =4(a+b+c)

*February 20, 2017*

**no way**

You say rectangle. I assume typo? Did you read what you wrote? All terms in the area are - ? -17.5 x^2 -138 x - 27 = 231? +17.5 x +138 x + 258 = 0 x = -3.05 or x = -4.84

*February 20, 2017*

**College Algebra**

f = 3(6x-5)^2 -4 = 3 (36 x^2 -60 x +25) - 4 = 108 x^2 -180 x +71

*February 20, 2017*

**Physics**

How much Ke should she have at 328 m? m g h = 71(9.81)(1370-328) Joules How much Ke does she actually have? (1/2) m v^2 = (1/2)(71)(68)^2 The difference is how much work is done by air friction. ========================== At 328 meters she has a total energy of m g 328 + (1/2...

*February 20, 2017*

**value**

log x^n = n log x a 2a 3a 4a .......

*February 20, 2017*

**Physics**

1/d^2

*February 17, 2017*

**algebra**

e^[2(3x^2-2)]

*February 16, 2017*

**Math**

small = s and b = big s = b-2 1/s + 2/b = 5/12 so 1/(b-2) + 2/b = 5/12 agreed multiply by 12 b (b-2) 12 b + 24(b-2) = 5 b(b-2) 12 b + 24 b - 48 = 5 b^2 - 10 b 0 = 5 b^2 - 46 b + 48 0 = (b-8)(5b-6) so use b = 8 s = b-2 = 6

*February 16, 2017*

**Physics**

normal force = m g max static = .75 m g so m a = .75 m g for slide to start or a = .75 g now the slide a = .75 g v = a t 33 = .75 g t t = 33/(.75*9.81)

*February 16, 2017*

**physics**

m g h = m g (3.4/2)

*February 16, 2017*

**Physics - Calculating work required**

This is a problem about POTENTIAL! The path does not matter ! That is the whole point. The voltage potential difference is the difference in potential energy of a unit charge at the two voltages. work done = charge * change in V

*February 16, 2017*

**Physics**

force = 55*9.81 Newtons pressure = force/area if area is in meters^2 then force is in Pascals

*February 15, 2017*

**physics**

Vi = 110,000 meters / 3600 seconds v = Vi + a t at end, v = 0 so 0 = Vi -49 t t = Vi/49 then d = Vi t + (1/2) a t^2 d = Vi (Vi/49) - (1/2)(49)(VI^2/49^2) d = (1/2)Vi^2/49

*February 15, 2017*

**Algebra**

I worked it out in the way you are probably used to. Scroll down

*February 15, 2017*

**Algebra**

44+47 = ? mi/h time = 69/speed

*February 15, 2017*

**Math**

divide by 1,000 kg/tonne

*February 15, 2017*

**arrgh upside down**

.3456/.84 = .4114

*February 15, 2017*

**too-hard probability sir damon/reiny/steve help**

He did, right here: P(w ? 0) = 1 - P(b = 4) = 1 - .4^4 P(b = 2) = 6 * .4^2 * .6^2 =============================== prob of some white = 1-.4^2 = .84 the prob of 2 black = 6*.4^2*.6^2 = .3456 divide .84/.3456 so

*February 15, 2017*

**too-hard probability sir damon/reiny/steve help**

LOL use Scott's answer. I used 10 for number of trials, did not read correctly.

*February 15, 2017*

**too-hard probability sir damon/reiny/steve help**

I got .121/.929 = 0.130

*February 15, 2017*

**too-hard probability sir damon/reiny/steve help**

well using C(n,r) for 2 black p(b) =.4 p(not black) = .6 n = 10 r = 2 P(10,2) = C(10,2) .4^2 .6^8 C(10,2) = 10!/[8! 2!] = 10*9/2 = 45 so 45 * .16 * .0168 =.121 now for no whites, that is P of 4 blacks 6/10 * 5/9 * 4/8 * 3/7 = .0714 1-.0714 = .929 = probability of at least one...

*February 15, 2017*

**Math HELP**

A is 3,4,5 so right B is right C 36 + 289 = 400 ?? I think not D 12.25 + 144 = 156.25? Yes, so right

*February 15, 2017*

**Typo**

rho = 2.04 kg/5.1*10^-4 m^3 = 4 * 10^3 kg/m^3

*February 15, 2017*

**Physics**

Please proof read what you wrote. It has got to be backwards. the density of the cube I suppose :) displaces water weighing 5 Newtons 5 N = 1000 kg/m^3 * 9.81 * Volume so Volume = 5.1* 10^-4 m^3 mass = 20 N in air I think/9.81 = 2.04 kg so rho = 2.04 kg/5.81*10^-4 m^3 = 3.51...

*February 15, 2017*

**Math question**

The volume of something pointy with straight sides is the base area times the height divided by three. V = (1/3) pi r^2 h = (1/3)(3.14) (1)^2 (9) = 9.42 in^3 to get the value multiply by 2 = $ 18.84 so I agree

*February 15, 2017*

**inverse correct - can not help with image**

For inverse check multiply |0 +6| |-1/2 1/4| |4 12| |+1/6 +0 | = 1 0 0 1 so right ! I have no idea what the image is about

*February 15, 2017*

**science**

What you are looking at is essentially an adiabatic expansion of the air as the pressure goes down (It does not gain or lose heat.) In an adiabatic expansion the temp goes down. http://en.wikipedia.org/wiki/Adiabatic_process

*February 15, 2017*

**science**

http://www.engineeringtoolbox.com/air-altitude-temperature-d_461.html

*February 15, 2017*

**science**

Do you know about Coriolis? One way to think about it: 1. say you have a low pressure spot in the northern hemisphere. 2. a parcel of air south of that spot will head north, toward the low pressure. 3. That parcel was moving east at the speed of the earth surface at that ...

*February 15, 2017*

**Math**

yes there are tricks to do these in your head like 15% is 10% + 5% 12.5 * 2 = 25 5% = (1/2) 10% etc

*February 14, 2017*

**Math**

(1/6)(1/2) = 1/12

*February 14, 2017*

**same question over and over and over**

delta L /L = k * delta T

*February 14, 2017*

**Math**

I you have two 25 degree angles in a triangle, the third one must be 130 degrees

*February 14, 2017*

**Math**

I guess you mean the two equal angles are each 25 since the sum must be 180 50 + x = 180 x = 130

*February 14, 2017*

**tecca math**

5,237

*February 14, 2017*

**huh?**

What do you mean? Are you missing parentheses or something?

*February 14, 2017*

**Logarithms**

x^log3(x) = 3^9 log3 (x^log3(x) = log3(x) log3(x) = 3^9 log3 (x) = 3^(9/2) = 3^4.5 = 140.3 3^log3(x) = x = 3^140.3 check my arithmetic, did quickly

*February 14, 2017*

**Logarithms**

2 log8 (8) - .5 ln (e) 2 - .5 = 1.5

*February 14, 2017*

**Logarithms**

log8 (5^8) - log8(7) = log8 (5^8/7)

*February 14, 2017*

**algebra**

3x^2 - 5x + 2 = 0 a = 3 b = -5 c = +2 So I think the last one. if they ask for zeros (3x-2)(x-1) = 0 x = 2/3 or x = 1

*February 14, 2017*

**maths**

70*44*3 = 6 * pi (17.5)^2 t t = 70*44*3/[6*pi*17.5)^2] seconds divide by 3600 to get hours

*February 14, 2017*

**math**

train 1, x= 45*3 = 135, y = 0 dx/dt = 45 train 2, x = 0, y= -60*3 = -180 dy/dt = -60 z = hypotenuse z^2 = x^2+y^2 = 3^2 (45^2+60^2) = 3^2 (2025 + 3600) = 3^2(5625) so z = 3*75 = 225 z^2 = x^2 + y^2 2 z dz/dt = 2 x dx/dt +2 y dy/dt dz/dt = (xdx/t+ydy/dt)/z = (135*45-180*-60)/...

*February 14, 2017*

**algebra**

cos 75 = x/15

*February 14, 2017*

**maths**

L = 6 + 2 p W = 4 + 2 p 56 = (6+2p)(4+2p)-6*4 56 = 24 + 20p + 4p^2 -24 4 p^2 + 20 p - 56 = 0 p^2 + 5 p - 14 = 0 (p+7)(p-2) = 0 p = 2

*February 14, 2017*

**maths**

2 see above http://www.jiskha.com/display.cgi?id=1487067037

*February 14, 2017*

**Math**

4 b + 5 y = 49 2 b + 1 y = 17 4 b + 5 y = 49 10b + 5 y = 85 -----------------subtract -6 b = -36 b = 6

*February 14, 2017*

**Math 115**

6*1/2 = 3 while you rest 3 + (1/60 mile/min)(t-40)

*February 14, 2017*

**physics**

k Q1 Q2/ d^2

*February 13, 2017*

**Math**

to multiply by 100 while driving without a calculator: Stop the car by the side of the road. Move the decimal point two spaces to the right. Resume driving.

*February 13, 2017*

**Math**

42 animals 18-6 = 12 female cats prob of female cat = 12/42 now we have 41 animals, 11 females cats prob of female cat = 11/41 so 12/42 * 11/41

*February 13, 2017*

**Math**

-6x + 6 +3x = -3x + 6

*February 13, 2017*

**Math**

a + s = 220 7 a + 5.5 s = 1390

*February 13, 2017*

**Math/pre-algebra**

(.25 in / 6 ft) is our conversion factor 18 ft (.25 in/6 ft) = .75 in 66 (.25/6) = 11/4 204 (.25/6) =

*February 13, 2017*

**Needs Chemistry**

Not my thing, sorry

*February 13, 2017*

**Physical Science**

O has 8 protons and 8 neutrons. normally it has 8 electrons as well when it is neutral HOWEVER if it has a charge of +1 (unusual for O by the way) then it lost one of those 8 electrons and is left with 7

*February 13, 2017*

**calculus**

find y at the end (x = 10) find y at the beginning (x=3) subtract Yend - Ybegin divide that by 10-7 which is 3

*February 13, 2017*

**Physical Science**

You are welcome.

*February 13, 2017*

**Physical Science**

If it were A, it would be black :) If it were C, it would emit the transition spectra of the metal If it were D, yu would not see it at all :) So I think we pick B, which contains the handy word "reflect".

*February 13, 2017*

**physics**

during the stop, which starts at 20 and ends at 0, the average angular velocity is 10 rad/s 1 rev = 2pi rad 15.92 revs = 2*pi*15.92 rad so 2 pi * 15.92 rad/10 rad/s = about 10 s, yes I agree with teacher

*February 13, 2017*

**calculus**

I am a physicist so call your y "v", velocity and your x is "t" d = integral v dt d is integral from 1 to 5 of (t^2 -9) dt = t^3/3 - 9t at 5 - at 1 at 5 it is 125/3 - 45 at 1 it is 1/3 - 9 -------------------subtract 124/3 - 36

*February 13, 2017*

**Stat**

http://davidmlane.com/hyperstat/z_table.html

*February 13, 2017*

**physics**

forget cm, doing seconds and meters - SCI units Pe = (1/2) k |x|^2 Ke = (1/2) m |v|^2 so for Ke = 1/2 Pe m |v|^2 = .5 k |x|^2 but ?^2 = k/m so |v|^2 = .5 ?^2 |x|^2 At our spots [A ? cos ?t]^2 = .5?^2[A sin ?t]^2 A^2 ?^2 cos^2?t = .5?^2 A^2sin^2wt cos^2 ?t = .5 sin^2 ?t cos^2 ?...

*February 13, 2017*

**p**

I already did one like this for you.

*February 13, 2017*

**physics**

.35 meters in half a period, T/2 2 A = .35 x = A sin 2 pi f t x = A sin (2 pi t/T) max at T/4 min at 3T/4 3T/4 - T/4 = time between max and min = T/2 so 0.30 m/s = 0.35 m /(T/2)s T/2 = 0.35/.3 T = 7/3 seconds w = ang freq = 2pi/T = 6 pi/7 max a = w^2 A = (6pi/7)^2(.35/2) max v...

*February 13, 2017*

**physics**

I took this course in 1955 and no longer need practice. You are asking basically the same question over and over. I am happy to help but have done enough of them for you. since it is not extended at the start use y= A cos 2 pi t/T which is A at t = 0 and hits the lowest point...

*February 13, 2017*

**physics**

Hey, you do some now !

*February 13, 2017*

**Social Studies**

This is much more how I remember it: http://www.georgiaencyclopedia.org/articles/government-politics/worcester-v-georgia-1832

*February 13, 2017*

**Social Studies**

That decision I just looked up is not how I remember it in fact. I thought the Supreme Court sided with the tribes and Andrew Jackson kicked the tribes west anyway. Yes, what the above says is that white settlers can not be prohibited from trespassing on native property.

*February 13, 2017*

**Social Studies**

from Google: 515 (1832), was a case in which the United States Supreme Court vacated the conviction of Samuel Worcester and held that the Georgia criminal statute that prohibited non-Native Americans from being present on Native American lands without a license from the state ...

*February 13, 2017*

**physics**

sqrt (37^2+44^2) = 57.49 = 57 meters tan angle = 44/-37 angle = -50 x is - and y is + so second quadrant 180 - 50 = 130

*February 13, 2017*

**Geometry**

another one?

*February 13, 2017*

**Math**

e^0.018t = 20/12 .018 t = ln (20/12) = .511 t = 28.4 years

*February 13, 2017*

**physics**

ke = (1/2)(5.4) (6.2)^2 stops so all ke converted to U U = m g h = ke from first part 5.4 (9.81) h = answer from part 1

*February 13, 2017*

**physics**

d = (1/2) a t^2 8 = .5 a (16) so a = 1 m/s^2 v = a t = 1 (4) = 4 m/s or use head like this average speed = 8 m/4s = 2 m/s begin speed is zero so final speed = twice average speed = 2*2 = 4 m/s

*February 13, 2017*

**math algebra**

log x^n = n log x so you have log x (1+2+3+4 ...120) so log x times arithmetic sequence sum with a = 1, d = 1 n from 1 to 120 see http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html

*February 12, 2017*

**Algebra**

|3y+4| means absolute value of 3y+4 -| means nothing to me.

*February 12, 2017*

**huh**

typo ?

*February 12, 2017*

**physics**

1 m^2 = 10,000 cm^2 20 * 10,000 = 200,000 N/m^2 400 cm^2 = 400/10,000 = .04 m^2 200,000 * .04 = 2000*4 = 8,000 N of weight about 800 kg mass if g = about 10m/s^2, small car :)

*February 12, 2017*

**math**

I said "which it is".

*February 12, 2017*

**math**

I suspect they mean every diameter of a circle is a chord, which it is.

*February 12, 2017*

**Math**

no 2 * 96 / .75 is not 640

*February 12, 2017*

**Ecconomics**

so you want the intersection? 15 - .2 p = -3 + .4 p .6 p = 18 p = 180/6 = 30 q = -3+12 = 9

*February 12, 2017*

**Math**

300 (1.00) - 300 (0.05) = 300 (0.95) = 285

*February 12, 2017*

**is it falling?**

if so then v = -gt d = -(1/2) g t^2 from second two to second three: d = -(1/2)g (9-4) = -(5/2) g from second three to second four: d = -(1/2)g (16-9) = -(7/2) g ratio = 7/5

*February 12, 2017*

**ed tech**

The software on this site does not allow copy and paste.

*February 12, 2017*

**ed tech**

You can not do that, sorry.

*February 12, 2017*

**Algebra**

diver 1 depth = 12 - 1 t diver 2 depth = 15 - 2 t so 12 - t = 15 - 2 t t = 15-12 t = 3 seconds 12 - t = 12 - 3 = 9 meters

*February 12, 2017*