Saturday

August 29, 2015
Total # Posts: 21,799

**algebra**

-2 v - 7 = -23 add 7 to both sides -2 v = -23 + 7 = -16 divide both sides by -2 v = -16/-2 = +8
*December 22, 2014*

**AP CALC**

sin 3 pi/2 = sin 270 = -1 sin - 3 pi/2 = +1 change in sin x = -1 - +1 = -2 change in x = 3 pi/2+3pi/2 = 3 pi so slope from left to right = -2 / 3pi = -.2122 so where does the derivative of sin x = -.2122 ? d/dx (sin x) = cos x so cos x = -.2122 x = 102.25 degrees = 1.78 radians
*December 21, 2014*

**Physics**

if initial speed in +x direction impulse = change of momentum .0420 (-7.4 - 18.3)
*December 21, 2014*

**ap calc**

when x = 2, y = 2(4)-8+3 = +3 when x = 0, y = 2(0) -0^2 = 0 delta y/delta x = (3-0)/2 = 1.5 so where in there does f' = 1.5 ? between 0 and 1 f' = 2 - 2x so 2 - 2x = 1.5 2x = .5 x = .25 is one spot between 1 and 2 f' = 4 x - 4 so 1.5 = 4 x - 4 4 x = 5.5 x = 1.375 ...
*December 21, 2014*

**Physics**

call + x direction the initial direction of the first (3 kg) mass initial momentum = 3*2 -5*2 =6-10 = -4 final momentum also -4, mass = 8 8 * v = -4 v = -1/2
*December 21, 2014*

**ap calc**

h = e^sin x h' = cos x e^sin x cos pi/2 = 0 sin pi/2 = 1 so 0 * 1 = 0
*December 21, 2014*

**been there done that**

I just did this a little while ago
*December 21, 2014*

**math**

0.34* 10^7 + 4.7 * 10^7 = 5.04 * 10^7 but you are only using 2 significant figures so 5.0 * 10^7
*December 21, 2014*

**math i really need help!!**

5.93 * 10^5 - 0.271 * 10^5
*December 21, 2014*

**College Math**

probably sqrt (30)
*December 21, 2014*

**physics**

Now this is very similar but easier than the one you threw up from the roof of the building. You try it. I have grand kids playing hockey now.
*December 21, 2014*

**physics**

That t top in part B is the time to slow down on the way up from the top of the building to the max height. 10/9.81 seconds. THEN, it starts falling from that top point I called Htop. By the way it will pass the roof on the way down at 10 m/s down :)
*December 21, 2014*

**physics**

v = Vi - 9.81 t v = 0 at top so t = 10/9.81 at top (part B) Htop = 150 + 10 t - 4.9 t^2 (part A) now simply drops from Htop to ground Pe at top = m g Htop Ke at bottom = (1/2) m v^2 so v = sqrt (2 g Htop) (part C) we have original t rising to top now time falling v = 0 + g ...
*December 21, 2014*

**math**

6/9 = 2/3 chance of not blue on each pick if replaced, then independent 2/3 * 2/3 * 2/3 = 8/27
*December 21, 2014*

**algebra**

2 s + 5 a = 950 s+a = 250 so a = 250 - s 2 s + 5 (250-s) = 950
*December 21, 2014*

**Physics- revolutions**

Ac = v^2/r so .7 = .013 v^2/.93 solve for v we know r time = distance / speed = 2 pi r/v
*December 21, 2014*

**phys**

F = m a = 70 * acceleration = 70 * 5 * 9.81
*December 21, 2014*

**Physics~**

You are welcome :)
*December 21, 2014*

**Physics~**

sqrt (ge/gm) = sqrt 6 times period on earth
*December 21, 2014*

**Physics**

.145 * 9.81 - .4 = 1.022 N down a = F/m = 1.022/.145 = 7.05 m/s^2 down I get
*December 21, 2014*

**Static Friction..I really Have no Idea**

maximum friction force = mu m g = .2 * .4 * 9.81 = .787 Newtons so it is less than or equal to .787 Newtons (or .78 N if you use 9.8 for g and round to two significant figures)
*December 21, 2014*

**chemistry**

p V = n R T p/RT = n/V = constant here n of H2/V of H2 = n of NH3/V of NH3 V of H2 = (n of H2/ n of NH3)100 cm^3 for every 2 mols of NH3 you get 3 mols of H2 so n of H2/n of NH3 = 1.5 so V = 1.5 * 100 = 150 cm^3
*December 21, 2014*

**Physics**

T - m g = m a T = 10.0 (9.81 + 1.50)
*December 21, 2014*

**Math**

8 + 3 = 11 37 + 15 = 52 so 11:52 pm
*December 21, 2014*

**Wolfram disagrees with me, check my algebra**

http://www.wolframalpha.com/input/?i=plot+xln%28x%29%2B+%281-x%29ln%281-x%29
*December 21, 2014*

**ap calc**

y = x ln x + ln(1-x) - x ln (1-x) = ln x^x + ln [ (1-x)/(1-x)^x = ln [ x^x (1-x)^1/(1-x)^x ] = ln [ x^x (1-x)^(1-x) ] let z = 1-x dz = - dx y = ln [ x^x z^z ] = ln x^x + ln z^z = x ln x + z ln z y' = x (1/x) + ln x + z(1/z)dz/dx + ln z dz/dx = 1 + ln x -1 - ln(1-x) = 0 all...
*December 21, 2014*

**ap calc**

y = sin x y' = cos x I guess that is -3 pi/2 to + 3 pi/2 sin 3 pi/2 = -1 sin -3 pi/2 = 1 -1 - 1 = -2 -1/(3 pi) = -.1061 cos^-1 -.1061 = 96.1 degrees = 1.677 radians cos is odd function so also -1.677 radians
*December 21, 2014*

**History**

He sent General Zachary Taylor to claim an area of disputed land for the United States. http://en.wikipedia.org/wiki/South_Pass_%28Wyoming%29 The journey was surprisingly easy. the idea that it was God's plan for the nation to expand across the continent
*December 21, 2014*

**Math-How do I do this problem?**

sure change in volume = surface area * change in depth or dV = pi r^2 dh dV/dt = pi r^2 dh/dt = 12 ft^3/min so dh/dt = 6/(pi r^2) if r = 7, h = 24 or r = (7/24)h = (7/24)(10) = 70/24 so dh/dt = 6 / [ pi (70/24)^2 ]
*December 21, 2014*

**physics**

two arrows right, one left <-.------>-->
*December 21, 2014*

**multiplcation**

6*1000 = 6000 6*700 = 4200 6*50 = 300 6 * 0 = 0 ------------------add 10500
*December 21, 2014*

**math**

p = price of kerosene/liter 5 p/3 = price of diesel 5 p = price of petrol x = liters of diesel purchased cost of x liters of diesel = 5 x p/3 = 510 cost of x liters of kerosene = x p but x p = (3/5)(510) = 306
*December 21, 2014*

**Calculus**

6 x dx + 2 y dy = 0 dy/dx = -3 x/y at (1,2) this is-3/2 d^2y/dx^2 = -3 [ y - x dy/dx ]/y^2 at (1,2) = -3[2+3/2]/4
*December 21, 2014*

**calculus**

ln y = 3 x ln (x+8) (1/y ) dy/dx = 3x[1/(x+8)] + 3 ln(x+8) dy/dx = 3x(x+8)^3x {[1/(x+8)]+3 ln(x+8)}
*December 21, 2014*

**Calculus**

dy/dx = 2 x so -1/slope = -1/2x = -1/4 y = -x/4 + b 9 = -1/2 + b b = 9.5 y = -x/4 + 9.5 4 y = -x + 38
*December 21, 2014*

**Math**

dy/dx = 3 x^2 + 10 x -8 yes 0 d^2y/dx^2 = 6 x + 10 positive so min at 0 I get about .2 so not 0 so I think only A
*December 21, 2014*

**Physics- Horizontal Velocity**

You dropped it from 5 meters and it went 25 meters maybe ?? If so: time to drop 5 meters 5 = (1/2)(9.8)t^2 t = 1.43 seconds u = 25 m/1.43 s = 17.5 m/s
*December 21, 2014*

**Biology**

Sometimes mechanical (rubbing) , sometimes chemical (reacting with O2), etc. The one thing you can count on is that whatever happens, it will end up losing heat to the environment :)
*December 19, 2014*

**physics please help**

Bart does 400/60 m/s how many meters does he do in 58 s ? (when Wyatt finishes) 400 (58/60) = 386.66666666666666666667 400 - that = 13.3333333333 meters
*December 19, 2014*

**NEED HELP ASAP PHYSICS**

35.79 miles per hour { Google 16 m/s = miles/hour } a = change in velocity/change in time = -16/.08 = -200 m/s^2
*December 19, 2014*

**did that**

see question above
*December 19, 2014*

**physics**

stuff shoots out the rear, body moves forward Conservation of momentum (Newton #1) initial momentum before reaction = 0 so momentum of body/exhaust system remains zero forever therefore if exhaust moves back then body must move forward to keep the total momentum zero
*December 19, 2014*

**Helppp**

1 2 3 4 5 ---- 5.5 ---- 6 7 8 9 10 1 2 3 4 5 ----- 6 ----- 7 8 9 10 11 so A = 5.5 B = 6 11.5/2 = 5.75
*December 19, 2014*

**math**

No, .025*2,015,000 is the commission. You wrote what the seller gets after commission.
*December 19, 2014*

**Juba Day SS**

10/20 * 9/19 10/20 * 3/19 7/20 * 3/19
*December 19, 2014*

**PRE-ALGEBRA MRS.SUE PLEASE!!!!!!!!!**

Did you read my answer below? I have answered this question twice. 59.95/11.99 = 5 so you can buy 5 you can also buy four or three or two or one or none
*December 18, 2014*

**PRE-ALGEBRA MRS.SUE PLEASE!!!!!!!!!**

We can not always answer instantly.
*December 18, 2014*

**PRE-ALGEBRA MRS.SUE PLEASE!!!!!!!!!**

Check below you are fine except for #8 and #10
*December 18, 2014*

**PRE-ALGEBRA**

59.95/11.99 = 5 so you can buy 5 you can also buy four or three or two or one or none Please do not submit the same question twice !
*December 18, 2014*

**PRE-ALGEBRA**

1. 7 yes 2. 8 yes 3. 7x + 5 = 4x + 5 + 3x yes 5. k < 0 yes 6. q ≥ –1 yes 7. p < 8 yes 8. g > –90 #####I get g >90#### 9. n – 6 ≥ 2; n ≥ 8 yes 10. ??????? n </= 5 you could buy one or 4 but not 6
*December 18, 2014*

**Algebra 1**

since 7 x and -7 x appear just add the two equations to eliminate x like: 3 y = 3
*December 18, 2014*

**Math**

n/(n+1) (n+2) /[(n+1)+2 ] = 4/5 (n+2) / (n+3) = 4/5 5(n+2) = 4(n+3) 5 n + 10 = 4 n + 12 n = 2 2/3
*December 18, 2014*

**Science yes, agree**

Check my answers please? Imagine that you remove all the atoms from a chair. What remains? 1. nothing 2. a pile of dust I choose 1. YES Which of the following is not made of atoms? 1. heat 2. a solid 3. a gas I choose 1. YES What about matter is true? 1. atoms are not matter ...
*December 18, 2014*

**Algebra 1**

x-1 = -3x -5 4 x = -6 x = -1.5 y also negative yes quad three
*December 18, 2014*

**math**

or we could say 3/4 = Juice /(32-juice)
*December 18, 2014*

**math**

there are 3+4 = 7 parts
*December 18, 2014*

**math**

(3/7)32
*December 18, 2014*

**statistics**

http://davidmlane.com/hyperstat/z_table.html
*December 18, 2014*

**algebra 1**

use FOIL or distributive property (same thing really) 7 p^2 + 10 p + 3 or 7p (p+1) + 3 (p+1) = 7 p^2 + 7 p + 3 p + 3 = 7 p^2 + 10 p + 3 again
*December 18, 2014*

**math**

5 years = 20 quarters at .05/4 = .0125 per quarter 1.0125^20 = 1.282037232 so 55,000/1.282037232 = $ 42,900.47
*December 18, 2014*

**Honors Physics**

Try to answer and we will look.
*December 18, 2014*

**Honors Physics**

Honors physics?
*December 18, 2014*

**algebra 1**

10 x - 24 y = -6 10 x - 4 y = -25 ----------------- 0 x - 20 y = 19 y = -19/20 etc
*December 18, 2014*

**phy**

a up on 6 kg mass, so down on 10 kg mass 6 kg mass T - 6 g = 6 a 10 kg mass 10 g - T = 10 a add 4 g = 16 a a = g/4 then go back T - 6 g = 6 g/4 T = 7.5 g = 7.5(9.81)
*December 18, 2014*

**algebra**

40 + n = 10 + 4 n 30 = 3 n
*December 18, 2014*

**Math**

.65 * 80 100 (.65*80)/327
*December 18, 2014*

**Math**

(4x-1)/[(x+3)(x+4)] * (x+4)(x-3)/(2x-1) the (x+4) cancels, not much else to do
*December 18, 2014*

**Math**

I think it just blows up if x = -3
*December 18, 2014*

**Math**

x(x-2) /(x+1) * (x+1)(x-1)/[(x+3)(x-2)] = x (x-1)/(x+3)
*December 18, 2014*

**math solution on algebra**

half this triangle is a 30, 60, 90 triangle with the altitude (sqrt 3) as the long leg and half(1) the base as the short leg. (1/2) b h = (1/2)(2) sqrt 3 = sqrt 3
*December 18, 2014*

**physics**

Vi = 54 sin 39 v = Vi - 9.8 t v = 0 at top so t = Vi/9.8 at top use that t h = Vi t - 4.9 t^2 it will turn out to be 1/2 Vi t
*December 17, 2014*

**Please look for reply before posting again**

I did that a lot of questions ago.
*December 17, 2014*

**physic**

http://www.jiskha.com/display.cgi?id=1418842081
*December 17, 2014*

**physic**

been there, done that
*December 17, 2014*

**calculus honor**

assume you mean y = 2 x^3 - 4 x dy/dx = 6 x^2 - 4 if x = 1 dy/dx = 6-4 = 2
*December 17, 2014*

**calculus honor**

V = x^2 h dV/dx = 2 x h dV/dh = x^2 dV/dt = dV/dx dx/dt + dV/dh dh/dt x = 4 h = 15 dV/dt = 120 dx/dt + 16 dh/dt = 120(2) -16(3) = 240-48
*December 17, 2014*

**done that**

I did this one a while ago as well :(
*December 17, 2014*

**calculus**

A = pi r^2 A/dr = 2 pi r (which is the circumference of course, draw a circle and a ring of thickness dr on the outside and look at the added area) if r = 5 dA/dr = 10 pi =================== this is most interesting if the radius is changing with time r = k t dr/dt = k dA/dt...
*December 17, 2014*

**physic**

power = work/time work = weight * distance up = 475*9.81*10 so power = 475*9.81*10 / 24 Joules/second or Watts divide by 1000 for kilowatts
*December 17, 2014*

**Math( Can you help me with starting this problem)**

dV/dr = area of surface = 4 pi r^2 so dV/dt = 4 pi r^2 dr/dt so dr/dt = (dV/dt) / (4 pi r^2)
*December 17, 2014*

**Physics**

If .392 Newtons is pulling it at constant speed then the friction is equal and opposite to the pull .392 = mu m g = mu (.2219)(9.81)
*December 17, 2014*

**Algebra**

height = 5 (L-10)(w-10)5 = 1760 (L-10)(w-10) = 352 L = 2 w (2w-10)(w-10) = 352 (w-5)(w-10) = 176 w^2 - 15 w + 50 = 176 w^2 - 15 w - 126 = 0 (w-21)(w+6) = 0 so w = 21 L = 42
*December 17, 2014*

**Algebra 1**

slope = m = 3 10 = 3 (2) + b b = 4 y = 3 x + 4
*December 17, 2014*

**Physics**

If the angle is 90 degrees to the x axis it is all y axis 0 i + 9 j
*December 17, 2014*

**Science-Physics**

500 * 5 force in direction of motion times distance moved
*December 17, 2014*

**physics**

300 * 9.81 * 6 Joules
*December 17, 2014*

**Physics**

500 cos 37 - .5 (350 + 500 sin 37) = m a m = 350/9.81 find a 4 = (1/2) a t^2 for part be find mu for: 500 cos 37 - mu (350 + 500 sin 37) = 0
*December 17, 2014*

**Physic**

potentials add Q1/r = Q2/(.5-r)
*December 17, 2014*

**physics**

g = 9.81 m/s^2
*December 17, 2014*

**Physics**

51 = 4.9 t^2 solve for t d = 31 t v = 9.81 t vertical and 31 horizontal so speed = sqrt ( v^2+31^2)
*December 17, 2014*

**Physics**

angular speed = 2 pi(1.15/4.5) = omega v = omega * r = omega * 5.50 F = m a = m v^2/r = .655(v^2)/5.50
*December 17, 2014*

**physics**

(g - v^2/r) = .8
*December 17, 2014*

**math**

360,000 / 600 = = 3600/6 = 600
*December 17, 2014*

**Physics**

T - mg = ma T = m (g+a) = 2.13 (9.81 + 3.10)
*December 16, 2014*

**Math**

R + J = 48 J = .5 R + 6 R + (.5 R + 6) = 48 1.5 R = 42 etc
*December 16, 2014*

**math**

5 x + 3 y = 3213 y = 4 x 5 x + 12 x = 3213 17 x = 3213 x = 189 for digital 4 x = 756 for video sum = 945
*December 16, 2014*

**pre-algebra**

(-1)(-x) = (-1)(-7) +x = + 7
*December 16, 2014*

**algebra**

a = A e^rt a = 400 e^.076(1.5) a = 448.
*December 16, 2014*

**chemistry**

density ice = 4.3/5 = .86 g/cm^3 density of that oil = 27/30 = .9 g/cm^3 the ice is less dense than the oil. It will float
*December 16, 2014*