Friday

October 21, 2016
Total # Posts: 27,509

**????**

You forgot the equation

*February 24, 2016*

**physics**

20 east

*February 24, 2016*

**physics**

I assume you mean 8 hours. Velocity is the displacement /time and direction Here that is 320/8 or 40 mph North The 400 zigging and zagging is irrelevant for velocity but important if you wanted speed instead of velocity

*February 24, 2016*

**please help**

Please just do what I suggested. Goggle Mt Kilimanjaro and those countries.

*February 24, 2016*

**African climates - where to start?**

I do not know what to say. Except for one mountain (http://www.tanzaniaparks.com/kili.html) there is not much snow. However everything else is there :) Desert in the North, riverine in the Nile valley, jungle in the center and down the Congo river. Savannas, farmland, grazing ...

*February 24, 2016*

**science**

when the potential (voltage) is different in different places on the conductor.

*February 21, 2016*

**Science**

It doubles every (1/4) day? in 7 days it doubles 28 times 2^28 = 268,435,456

*February 21, 2016*

**Science**

Maybe you mean Bernoulli : (1/2)rho v^2 + rho g h + p = constant If flow is constant in time and no frictional losses rho = density h = altitude p = pressure g - gravitation acceleration v = speed

*February 21, 2016*

**Physics**

I can not sketch it for you. v = (2t+1.34) i + 3.34 j + (6t^2 - 8t) k so put in t = 2 a = 2 i + (12t-8) k again use 2 for t

*February 21, 2016*

**Physics**

A: v = 10 pi/(10.34) Ac = v^2/r = 20 pi^2/(10.34)^2 B: v = 20 pi/(10.34) Ac = 40 pi^2/(10.34)^2

*February 21, 2016*

**Maths**

(-4/3) x = 16/3 -4 x = 16 x = -4

*February 21, 2016*

**science**

60min/hr * 60 sec/min = 3600 seconds/hour 2 * 3600 + 35 = 7235

*February 21, 2016*

**Chemistry**

we are close to STP here where one mol is 22.4 liters 58.4/22.4 is around 2.61 moles 10.3/2.61 = 3.95 grams/mol Helium maybe ?

*February 21, 2016*

**Algebra**

Oh well, I'll play 300 = k * 3^2 * 10.62 so k = 300/(9*10.62) = 3.14 remarkable :) in fact v = pi r^2 h = pi * 3^2 * 10.62 = 300.27 :) so we say v = 3.14 * r^2 *h = 3.14 * 16 * 15.92 =785 cm^3

*February 20, 2016*

**Physics**

horizontal rope force= 100 cos 60 = 50 N so a) work done by tension = 50*15 = 750 Joules b) NONE !!!! there is no vertical displacement !

*February 20, 2016*

**Math**

.6 (299) = 179.4

*February 20, 2016*

**math**

I guess you mean circumference of a circle of radius 5.5 in if so 2 pi r = 11 pi

*February 20, 2016*

**High school calculus**

I have a extra b in there.

*February 20, 2016*

**High school calculus**

dy = (bx+5)^-3 dx let z = bx+5 then dz = b dx and dx = (1/b) dz dy = (1/b) z^-3 dz y = (1/b)(-1/2)z^-2 + c y = -1/(2b z^2) + c but z^2 = b^2x^2 + 10 bx + 25 so 2 b z^2 = 2b^3x^2 + 20 b^2 x + 50 b so y = -1/(2b^3x^2 + 20 b^2 x + 50 b) + c

*February 20, 2016*

**Algebra**

t = k r^2/z^3 4 = k 36/27 k = 3 so t = 3 r^2/z^3 ============================ c = k d^2/L .54 mho = k 3^2/50 k = 50 * .54 /9 = 3 again LOL (note - in your units which are not the ones a physicist would tend to use)

*February 20, 2016*

**math**

Some blame it on people like Pythagoras but I think folks along the Indus River thought it up to keep track of monsoons and crops and water level and stars and stuff. The really important guy was Sicilian but everyone calls him Greek named Archimedes. He not only figured out ...

*February 20, 2016*

**phy 231**

centripetal acceleration Ac = v^2/r = r omega^2 omega is part a r = radius there = Re sin 49 [ note - usually we use latitude which is angle North of the equator in this case cos(90-49)]

*February 20, 2016*

**physics**

(1/2) a t^2 = h (1/2)(9.81)(36) = h in meters

*February 20, 2016*

**math**

I can guess based on the possible answers. The only one with a y axis intercept is y = 5 x + 2 that is $2 to walk in the store and a unit rate of $5 per sandwich

*February 19, 2016*

**Statistics**

You are welcome.

*February 19, 2016*

**Statistics**

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

*February 19, 2016*

**Math**

http://www.jiskha.com/display.cgi?id=1455913440

*February 19, 2016*

**Just did it**

see below

*February 19, 2016*

**Math**

.80 * .75 * 179.99

*February 19, 2016*

**physics**

work output = 500 * 1.7 = 850 Joules work input = 1000 Joules efficiency = (850/1000)100 = 85 % since you did not say what the velocity ratio was, how would I know what the mechanical advantage was? They are the same on inverses depending of which way you write the velocity ...

*February 19, 2016*

**chemistry**

if they have more than one electron or lack of electrons in complete outer shell they can lose or gain electrons to form complete outer shells. Google oxidation reduction

*February 18, 2016*

**Physics**

100,000 meters/3600 seconds = 27.8 m/s d = 27.8 t d = (1/2)(3)(t-20)^2 so 18.5 t = t^2 -40 t + 400 solve quadratic for t

*February 18, 2016*

**Chemistry**

You do not say if you are in middle school, high school or college or what you are having trouble with. Google chemistry and you will find lots of stuff, for example: http://www.learnerstv.com/Free-chemistry-Video-lectures-ltv558-Page1.htm

*February 17, 2016*

**huh?**

Missing info, perhaps width of frame

*February 17, 2016*

**Physics/Eletrical engineering**

That is called a circuit.

*February 17, 2016*

**Chemistry**

5 grams of Na is 5/23 = .2174 mols so we get .2174 mols of NaBr NaBr = 23 + 80 = 103 grams/mol .2174 * 103 = 22.4 grams

*February 17, 2016*

**Physics**

http://www.jiskha.com/display.cgi?id=1455744206

*February 17, 2016*

**Physics**

Been there, done that. Check below

*February 17, 2016*

**Calculus**

If the first then dM/dt = -(1/3)(2t) + 1 = -2t/3 + 1 if t = 2 dM/dt = -4/3 + 3/3 = -1/3 the medicine is disappearing, presumably because it is eating bad guys.

*February 17, 2016*

**Calculus Please use parentheses**

-(1/3) t^2 + t or -1/(3 t^2) + t or 1/(3t^2+t)

*February 17, 2016*

**math, simple math**

which is e^(-x^2/a^2)

*February 17, 2016*

**Physics**

up 1 cm on 51 cm string cos A = 50/51 sin A = side force F/ Tension T tan A = F/(mg) so F/mg = tan 11.36 = .201 F = .001 (9.81)(.201) = .00197 Newtons F = Q E .00197 = Q * 9200 Q = 2.14 * 10^-7 Coulomb If motion in direction of E field, charge positive

*February 17, 2016*

**physics**

The center of mass will not accelerate, no external force on the system. That is a distance d from the 6000 kg asteroid 6000 d = 3580(400 -d) 6000 d = 1,432,000 -3580 d d = 149.5 meters from the asteroid so we need to pull the asteroid 149.5 meters 149.5 = (1/2) a t^2 where a...

*February 17, 2016*

**math age problem**

(r-2) , r , (r+8) 3 r + 6 = 60 3 r = 54 r = 18 so 16 , 18 , 26

*February 17, 2016*

**whoops**

sorry, use Reiny solution

*February 17, 2016*

**Trig**

cos 52 = (h-10.5) /12

*February 17, 2016*

**algebra**

one triangle is 20 by 30 the other is 30 by 30 sqrt(30^2+30^2) + sqrt(20^2+30^2)

*February 17, 2016*

**chemistry**

well, first it only has one electron. The spectrum gives you possible energy levels (states or orbit radius) for that electron.

*February 16, 2016*

**math**

h = 1000 x = sqrt (1250^2 - 1000^2) = 750 meters horizontal r = distance (hypotenuse) r^2 = h^2 + x^2 2 r dr/dt = 0 + 2 x dx/dt so dr/dt = (x/r) dx/dt = (750/1250)(800)

*February 16, 2016*

**math**

38 = 2 * 19 57 = 3 * 19 so 2/3

*February 16, 2016*

**Algebra**

Yes, an hour, 60 min

*February 16, 2016*

**Algebra**

stan speed = s lawns/min Hilda speed = 2s lawns/min (s + 2s) = total speed in lawns/min so (s + 2s) (20 min) = 1 lawn 60 s = 1 s = 1/60 lawns/min or 60 min/lawn

*February 16, 2016*

**Algebra**

80 t = 125 (t-1) 125 = 45 t t = 2.7777 hours or 2 hours and 47 min for car 1 and 1 hour and 47 minutes for car 2 check 80 * 2.777 = 222 125 * 1.777 = 222 good so 1 hour and 47 minutes

*February 16, 2016*

**Algebra**

420 - 20 = 400 420 + 5 = 425 so 400</= T </= 425

*February 16, 2016*

**Algebra**

8 parts total (3/8)(568) alcohol (5/8)(568) acid

*February 16, 2016*

**Algebra**

.04 x + .06 ( 67000-x) = 3440

*February 16, 2016*

**math**

I guess it starts at 0 height h = a x^2 + b x 148 = a (1)^2 + b(1) 272 = a(2)^2 + b(2) b = 148 - a 272 = 4 a + 2 (148-a) 272 = 4 a -2 a + 296 2 a = -24 a = -12 (should be 16 on earth but anyway) b = 148 +12 = 160 so h = -12 x^2 + 160 x if x = 6 h = -12*36 + 160(6) = 528

*February 16, 2016*

**Algebra**

f = 4 t 5 f + 10 t = 1050 so 20 t + 10 t = 1050 30 t = 1050 t = 35 tens

*February 16, 2016*

**Help please? Math 141 (Pre-Cal)**

as t gets huge the 84 and the 28 are small potatoes s ---> 51/3 = 17 16.5 = (51 t + 84)/(3t+28) solve for t

*February 16, 2016*

**Math**

are you doing geometric sequences maybe? 32 32*4.5 32*4.5^2 32*4.5^3 32 144 648 2916

*February 16, 2016*

**Physics**

Torque = I alpha Tension in line = T weight = m g = 1 * 9.8 = 9.8 N so 9.8 - T = 1(4.5) T = 5.3 N or kg m/s^2 torque = T * R = 5.3 R Nm or kg m^2/s^2 so 5.3 R kg m^2/s^2 = I alpha but a = alpha R so alpha = a/R so 5.3 R^2 kg m^3/s^2 = I kg m^2 * 4.5 m/s^2 I = 5.3 * .45^2 /4.5...

*February 16, 2016*

**physics**

assuming that then v = dx/dt = 2 A t + B a e^(at) acc = dv/dt = 2 A + B a^2 e^(at) now constraints at t = 0 -2 = B so 4 = -2 a a = -2 so in fact x = A t^2 -2 e^(-2t) v = 2 A t + 4 e^(-2t) acc = 2 A -8 e^(-2t) now at t = .2 , v = 5 so 5 = 2 A(.2) - 8 e^-.4 5 = .4 A - 5.36 A = ...

*February 16, 2016*

**?**

do you mean x = A t^2 + B e^(at) ?

*February 16, 2016*

**Social Studies (Check, Please!)**

Typo in #2 fight, they were old enough to fight. You mean VOTE

*February 16, 2016*

** jewellry**

Amma said to do what she typed, y = -3/x + 1

*February 16, 2016*

**Math-asymptotes**

ok if it is y = -(3/x) + 1 then clearly when x -->0 this becomes huge positive or negative depending on if x is positive or negative. That is the poit of vertical asymptotes as x becomes huge positive or negative, y---> 1 horizontal

*February 16, 2016*

**huh?**

do you mean y = -3/(x+1) or what you typed?

*February 16, 2016*

**Math**

2 cups / 36 cookies = x cups/ 60 cookies

*February 16, 2016*

**Math**

cran/gran = 1/3 1/3 = 3/x x = 9

*February 16, 2016*

**Algebra**

24.5 * 10^4 = 2.45 * 10^5 so yes, b

*February 16, 2016*

**Algebra**

correct, 100 is not twice ten

*February 16, 2016*

**Algebra**

a is actually 4.01 * 10^-5 so yes it is the biggest

*February 16, 2016*

**Algebra**

right

*February 16, 2016*

**Math**

You are welcome

*February 16, 2016*

**Math**

8/3 * 4/3 = 32/9 = 27/9 + 5/9 = 3 + 5/9 = 3 5/9

*February 16, 2016*

**Math**

8/8 + 1/8 = 9/8 4/2 + 1/2 = 5/2 so 9/8 * 5/2 = 45/16 = 32/16 + 13/16 = 2 13/16

*February 16, 2016*

**Math**

1 1/2 * 2 3/5 3/2 * 13/5 39/10 3 9/10

*February 16, 2016*

**URGENT! Due soon and I used 8 of 10 attempts**

.145 = (1/2)^n log .145 = n log .5 n = 2.786 half lives 2.786 * 5730 = 15963 = 1.5963*10^4 years

*February 14, 2016*

**precalc11**

check 700 * 1.0356^30 = 1999.99

*February 14, 2016*

**precalc11**

2000 = 700 x^(2000-1970) 2.857 = x^30 log 2.857 = 30 log x log x = .0151977 x = 1.0356 so 3.56 percent per year

*February 14, 2016*

**Physics**

total mass = 8.10+3.90 = 12.0 kg gravitational force = 3.90*9.81 = 38.3 N f = m a so a = 38.3/12 = 3.19 m/s^2 the 38.3 - T = 3.90 a = 3.90(3.19) T = 38.3 - 12.4 = 25.9 Newtons

*February 14, 2016*

**Physical science**

G = 6.67 * 10^-11 so 6.67*10^-11 * 1215^2 /(31)^2

*February 14, 2016*

**Physical science**

G M1 M2 /d^2

*February 14, 2016*

**MATH**

well, I guess we could use 6 - 2x for y 3 x + 2 (6-2x) = 6 3 x -4 x + 12 = 6 x = 6 then y = 6 - 2(6) = -6

*February 14, 2016*

**Chemistry**

HNO3/CU(NO3)2 = 4 mols /1 mol so 6/x = 4/1 4 x = 6 x = 1.5

*February 14, 2016*

**Math**

if x>/=0, y = 2-2e^-x if x <2, y = -1

*February 14, 2016*

**science chemistry**

note, absorbed high energy radiated much lower energy therefore, energy of atom went up.

*February 13, 2016*

**science chemistry**

http://www.jiskha.com/display.cgi?id=1455410600

*February 13, 2016*

**science chemistry**

Now I just did one using the same relationships between frequency, period, speed of light, wavelength and energy. This one is the same.

*February 13, 2016*

**Chemistry**

E = h f 3.2 * 10^-19 = 6.6*10^-34 f f = .485 * 10^15 Hz T = 1/f = 2.06 * 10-15 seconds if c = 3*10^8 m/s lambda =c T =3*10^8 * 2.06*10^-15 = 6.19 * 10^-7 meters = 619 * 10^-9 meters

*February 13, 2016*

**math**

Tara, the legs are 90 degrees from each other

*February 13, 2016*

**math**

north 55*3 west 65 * 3 hypotenuse = 3 sqrt (65^2+55^2)

*February 13, 2016*

**Chem**

4 mols of NH3 for every 3 of O2 so 4 4/3 = 8/6 so 6 of O2 also 4/2 = 8/4 so 4 of N2 4/6 = 8/12 so 12 of H2O I am getting bored :( 4/2 = 2/1 so 2 of NH3 3 of H2O enough already

*February 13, 2016*

**physics**

LOL, well we all know that pressure is density * v^2 but we better answer the question anyway. pressure = force/area = mass * acceleration / area^2 = M L/T^2 / L^2 = M /(L T^2) density = M/L^3 velocity = L/T so density * velocity^2 = M/L^3 *L^2/T^2 = M (L T^2) which sure ...

*February 13, 2016*

**Physics**

Google "Lagrange point"

*February 13, 2016*

**MATH>:(**

space 1, any of 7 space 2, any of 6 space 3, any of 5 etc 7! = 7*6*5*4*3*2*1 = 5040

*February 11, 2016*

**Pre-Calc**

(x+a)(x+a) x = -a or x = -a :) -a,-a (-a)^2 + 2a(-a) + a^2 a^2 - 2 a^2 + a^2 = 0 would you believe?

*February 11, 2016*

**Math**

height = 4 cm length = width = x-8 (x-8)(x-8)4 = 324 x^2 -16 x + 64 = 81 x^2 - 16 x - 17 = 0 (x-17)(x+1) = 0 well it is not -1 so x = 17 17 by 17

*February 11, 2016*