Thursday

August 21, 2014

August 21, 2014

Total # Posts: 17,955

**Math**

-1 * 14.8 -2 * 7.4 -4 * 3.7
*March 18, 2014*

**help i have no idea!!!!!!**

Now wait a minute, try this yourself.
*March 18, 2014*

**help i have no idea!!!!!!**

1 m/s * 5 * 60 = 300 so she has 100 left to walk
*March 18, 2014*

**help i have no idea!!!!!!**

d = rate * time 45 * 4 = rate * 5 rate = 45 * 4 / 5 = 36 km/h
*March 18, 2014*

**carver**

If each grandchild gets half a cup of sugar in punch, Bruce missed the class on nutritional errors.
*March 18, 2014*

**Linear Algebra**

That is fine as long as you did not skip any parentheses when you typed the question as Steve asked. We are all assuming that h^3 is in the numerator.
*March 18, 2014*

**Linear Algebra**

2 were wrong, he told you what was wrong.
*March 18, 2014*

**Physics**

work is the product of force and the distance moved in the direction of the force. No motion = no work
*March 18, 2014*

**physics**

Initial momentum = 2(200) -9(20) = 400 - 180 = 220 final momentum = 11 v Conservation of momentum, Newton's First Law ---> 220 = 11 v so v = 20 m/s
*March 18, 2014*

**Discrete Mathematics**

36 possibilities total white = 1 ---> 5 with white smaller white = 2 --> 4 . . . white = 5 --> 1 In other words 5+4+3+2+1 = 15 out of 36 15/36 = .417
*March 18, 2014*

**Math**

275 - 225 = 50 degrees difference in heading In two hours Ship A went 16 * 2 = 32 Sbip B went 20 * 2 = 40 c^2 = a^2 + b^2 - 2 a b cos C c^2 = (32)^2 + (40)^2 -2(32)(40)cos 50 c^2 = 1024 + 1600 - 1646.5 c^2 = 978.4 c = 31.3 For pert B, similar triangle, double time, double ...
*March 18, 2014*

**Quadratic Functions in Algebra**

x^2 - 6 x = C-20 x^2 - 6 x + 9 = C - 11 (x-3)^2 = C-9 vertex at x = 3,000 and cost = 900
*March 18, 2014*

**Algebra: Quadratic Functions**

-16 t^2 + 128 t = s - 70 t^2 -8 t = -s/16 + 4.375 t^2 - 8 t + 16 = -s/16 + 20.375 (t-4)^2 = -(1/16) (s - 326) vertex at time = 4 and height = 326
*March 18, 2014*

**Math**

5 green 20 total first green = 5/20 = 1/4 second green = 4/19 (1/4)(4/19) = 1/19
*March 18, 2014*

**College Math**

"Union" Anything in A, B or both 2 , 3, 5 , 6 , 7 , 9 http://mbaker.columbiastate.edu/algebratips_pages/union%20and%20intersection.htm 5 is the intersection of A and B by the way
*March 18, 2014*

**physics**

M is irrelevant at acceleration a, v = a T L = (1/2) a T^2 a = 2 L/T^2
*March 18, 2014*

**vocabulary power unit 5 grade 6**

synonym ----> two words that mean the same thing eg if you had HAPPY then A) miserable B) joyful C) sad E) cantankerous You would circle B (I think :)
*March 18, 2014*

**Math**

4/7 = x/4 x = 16/7
*March 18, 2014*

**math**

0.9 - 6 r -2 (0.2) 0.9 - 6 r - 0.4 0.5 - 6 r
*March 17, 2014*

**Math**

If you multiply the top and bottom of a fraction by the same thing you do not change the value of the fraction. 0.4 * 10 ----------- 0.2 * 10 is exactly the same as 4 ---- 2
*March 17, 2014*

**math**

20 x + 8 - 6 so 20 x + 2
*March 17, 2014*

**Physics**

work to lift = m g h = 750 * 9.81 * 13.2 Joules/minute work for Ke = (1/2)(750)(17.4)^2 Joules/minute C) add those and divide by 60 to get Joules/second or Watts
*March 17, 2014*

**math**

draw radii from center to the three intersections on the circumference all length r sine of half angle up at intersection of 13 cm legs = 5/13 so half angle = 22.6 deg isosceles triangle now with legs r meeting base 13 at 22.6 angle cos 22.6 = r/6.5 r = 6.5 cos 22.6 r = 6
*March 17, 2014*

**Physics**

weight = m g normal force down on floor N= m g+Fsin 28 friction force back = .25 N so F cos 28 = friction force back (a) F = friction force back / cos 28 force component in direction of motion = F cos 28 Newtons d = 4.1 meters so (b) Win = 4.1 F cos 28 Joules (c) -4.1 F cos 28...
*March 17, 2014*

**math**

30 + 10 w - w = 30 + 9 w
*March 17, 2014*

**Algebra**

(1/5) / 3 = 1/(5*3) = 1/15
*March 17, 2014*

**math**

.8 * 14 * 5 = $56
*March 17, 2014*

**chemistry**

CuNO3 molar mass = 63.5 + 14 + 3(16) = 125.5 grams/mol 8.22 g /125.5 g/mol = .0655 mols of the stuff .0655 mols/x liters = .59 mols/1 liter x = .111 liters
*March 17, 2014*

**Math**

2*3*2 = 12 4 of them are red (thick, thin, small Lg) 2 of them (a small and a large) -----------------red ---------small --yellow -----------------blue thick ------------------ red ---------large --- yellow -------------------blue -------------------red ---------small ----...
*March 17, 2014*

**Physics**

If your scale reads in grams or kilograms, that is mass assuming you do this on earth without acceleration (do not do it while in free fall before opening your parachute) If your scale reads in pounds, that is really force, not mass. Convert the pounds to kilograms.
*March 17, 2014*

**physics**

THINK !!! B goes up when current goes up, that is what causes B gets weak when you get away from wire of course. so the second choice
*March 17, 2014*

**Alegbra**

You do this one, same way as I did the other one.
*March 17, 2014*

**Alegbra**

8.2*10^5 / 2.75 * 10^-3 = (8.2/2.75) * 10^(5+3) = 2.98 * 10^8
*March 17, 2014*

**AP Calc**

sure, the base is y, the hypotenuse the center of the base is at y/2 half the base = the altitude
*March 17, 2014*

**AP Calc**

It is all in the first quadrant, base = y
*March 17, 2014*

**AP Calc**

area of triangle at x with base y: altitude of triangle is y/2, same as half the base so area = (y/2)(y/2) = y^2/4 y^2 = b^2 (1 - x^2/a^2) so y^2/4 = (b^2/4) (1 - x^2/a^2) integrate that from x = 0 to x = a
*March 17, 2014*

**College math**

LOL - now how am I to respond to that ? Thank you and you are welcome :)
*March 17, 2014*

**College math**

b^2 = 16 4 a c = 24 oh my b^2 - 4 a c is Negative :( That means we have a pair of complex conjugate roots
*March 17, 2014*

**PHS 105**

F = m a F is the same on both (Third Law) m2 a2 = m1 a1 10 m1 a2 = m 1 a1 a 2 = a1 /10 if a1 is 1 then a2 = 0.1 m/s^2
*March 17, 2014*

**scince i try i have no idea**

Google them for example force definition physics yields among other links: http://physics.info/newton-first/
*March 17, 2014*

**math**

200 * 1/3 is one way
*March 17, 2014*

**math**

9/16 or anything else greater than 1/2 and less than 1
*March 17, 2014*

**AP Calculus**

I assumed circumscribed meant outside, but it is unclear indeed.
*March 17, 2014*

**AP Calculus**

sketch the graph of e^x with the rectangles of height e^2, e^4 and e^6 and base of 2 each 2 e^2 + 2 e^4 + 2 e^6 = 2 (e^2 + e^4 + e^6)
*March 17, 2014*

**physical science**

Period = 1/f = (1/5.3)10^-14 seconds distance = speed * time lambda = 3*10^8 m/s * (1/5.3)* 10^-14 = .566 * 10^-6 meters = 566 * 10^-9 meters 10^-9 meters is nanometers, usually used for visible light wavelength
*March 17, 2014*

**physics**

P = angular momentum = I omega I1 = (1/2) m r^2 = (1/2)(4.7)(.17)^2 = .0679 P1 = (.0679) 2 pi (1.8) I2 = I1 + (1/2)(3.1) (.065)^2 = .0679 + .00655 = .0744 P2 = P1 so .0744 (2 pi)(rps) = .0679 * 2 pi *1.8 rps = 1.64 revs/s so I agree with you wholeheartedly
*March 17, 2014*

**Physics**

You are welcome :)
*March 17, 2014*

**Physics**

short string ----> higher frequency !!! f = k/L so (5/4) 440 = 550
*March 17, 2014*

**English**

Not Thanks but Satire :)
*March 17, 2014*

**math**

P = R - C P = 4 x - 2 x - 20 P = 2 x - 20 for 0 profit, x = 10
*March 17, 2014*

**math**

y = 5(1/x) is inverse 5 is the constant You only gave me one relationship.
*March 17, 2014*

**Physical Science**

This is the trouble with OTEC (Offshore Thermal Energy Conversion) where the difference in temperature between deep ocean water and water at the surface (in tropics of course) can be used to run a turbine system and generate electricity or whatever. However the efficiency is ...
*March 17, 2014*

**Physical Science**

if you mix hot and cold water and get warm water the entropy is higher, even if the energy did not change. The availability of that energy is what changed. Between a glass of hot water and a glass of cold water you can run an engine. However there is not much you can do with a...
*March 17, 2014*

**Physical Science**

increase
*March 17, 2014*

**Physical Science**

greater than Carnot cycle 1 - (Tcold/Thot) T in KELVIN (dge C + 273)
*March 17, 2014*

**Physical Science**

P V = n R T well, R does not change :) R = P V/(nT) = P' .5V /(.5n 2T) = P'(.5)V/(nT) so .5 P' = P P' = 2 P
*March 17, 2014*

**Physical Science**

Heat out = Specific heat of ice * mass of ice * change in temp
*March 17, 2014*

**Physical Science**

heat out = specific heat of water * mass of water * (30-0)
*March 17, 2014*

**Physical Science**

go boom !
*March 17, 2014*

**Physical Science**

heat in = SH * m * delta T SH = heat in / ( m* delta T)
*March 17, 2014*

**Physics**

F = k Q1 Q2 / d^2 = 9*10^9 * 1.6*10^-19*1.6*10^-19 / (26.1*10^-30) = .882 * 10^1 = 8.82 Newtons
*March 17, 2014*

**Dynamics**

m = 20*10^6 g = 20*10^3 kg v = 8000m/3600 s = 2.22 m/s Ke = (1/2) m v^2 = 10*10^3 * 4.94 = 4.94 * 10^4 Joules = (1/2) k x^2 x = .4 meter (wow!) x^2 = .16 (1/2) x^2 = .08 so k = 4.94 * 10^4/.08 =61.7 *10^4 N/m = 617,000 N/m
*March 17, 2014*

**Physics**

http://www.jiskha.com/display.cgi?id=1395061565
*March 17, 2014*

**Physics**

I did this already.
*March 17, 2014*

**Math plz help me!!! URGENT!!**

You are welcome.
*March 16, 2014*

**Math plz help me!!! URGENT!!**

(1/3) pi r^2 h = (1/3)(3.14) (100)(6) =628 mm^3 pi r L = 3.14 * 7 * 13 = 286
*March 16, 2014*

**Calc**

what is x is negative or zero Tim ?
*March 16, 2014*

**Calculus Help Please!!!**

I figured the same but he said specifically that a was variable.
*March 16, 2014*

**Calculus Help Please!!!**

2 y dy/dx = 2 x + 2 a da/dx y dy/dx = (x+a da/dx) dy/dx = (x + a da/dx)/y or dy/dx = (x + a da/dx)/(x^2+a^2)^.5 --------------------------------- 2 y dy/dx + a dy/dx + y da/dx = 2 x^2 + a + x da/dx + 2 a da/dx (2y+a)dy/dx = 2 x^2 +a +(x-y+2a)da/dx dy/dx = [2 x^2 +a +(x-y+2a)da...
*March 16, 2014*

**Physical Science 9**

2 H2O ----> 2 H2 + O2 That is a reaction in the outer valence electron shells so despite being a physicist, I call it chemical.
*March 16, 2014*

**physics**

initial momentum = 28000 u final momentum = (m+28000) v so 28000 u = m v + 28000 v initial ke = 14000 u^2 final ke = (14000+.5m)v^2 (14000+.5m)v^2 = .8 (14000 u^2) (14000+.5m)v^2= 11200 u^2 so I have these two equations to work with: 28000 u = m v + 28000 v and 11200 u^2 = (...
*March 16, 2014*

**Physics**

r = .14 meter w = omega, angular rate in radians/sec Ac = w^2 r F = m Ac 4*10^-11 = 3 *10^-16 (w^2)(.14) w^2 = 9.52 * 10^5 = 95.2 * 10^4 w = 9.76 * 10^2 radians/second rev = 2 pi radians 976 rad/s * 1 rev/2pi rad = 155 rev/s
*March 16, 2014*

**algebra**

- (-3)^2 - 5 (-3) + 6 - 9 + 15 + 6 21 - 9 12 your turn
*March 16, 2014*

**algebra**

You try first. Remember anything at all to the 0 power is ONE.
*March 16, 2014*

**Physical Science 9**

mass heat in = specific heat * mass * temperature rise
*March 16, 2014*

**Physical Science 9**

a compound
*March 16, 2014*

**Physical Science 9**

Pressure. When you reduce the pressure over a liquid surface to below vapor pressure, it boils off. If you increase the pressure, it does not boil until a higher temperature (eg - pressure cooker). The pressure is high enough in the can to hold the contents in a liquid state, ...
*March 16, 2014*

**math**

can vol = pi r^2 (10) = (22/7)(3.5)^2(10) = 385 cm^3 pan vol = 20*9*14 = 2520 cm^3 2520/385 = six and a half
*March 16, 2014*

**cal**

fx = 3 x^2 + 4 y level if x = +/-(4y/3)^.5 fxx = 6 x fxy = 4 fy = 4 x - 4 y level when x = y fyy = -4 fyx = 4 extreme only when x = y = 0 H matrix 6 x 4 4 -4 det = -6x - 4 if x = 0, det = -4 if det <0 then (0,0) is a "saddle point"
*March 16, 2014*

**math**

x^2 y = 2009 I fooled around factoring 2009 and the only square I found that was a factor was 49 49 * 41 = 2009 so 7 * 7 * 41 = 2009 so I have 2 faces that are 7*7 or 49+49 = 98 stickers then I have fours faces that are 7*41 so 4*7*41 = 1148 1148 + 98 = 1246 stickers used 2009...
*March 16, 2014*

**Physics - Current ????**

There is no current specified so row straight across :)
*March 16, 2014*

**Physics ?**

Why would I need a torque to move straight? why would I need any force to move at constant velocity? I am wondering who assigned this question.
*March 15, 2014*

**Math**

width = x length = y kitchen is 10 by x dining room is square so (y-10) = x kitchen area = 10 x dining area = x^2 so 10 x + x^2 = 264 x^2 + 10 x - 264 = 0 (x-12)(x+22) = 0 x = 12 y = x+10 = 22 so living room is 12 by 12 length is 22
*March 15, 2014*

**Calc**

I want a line perpendicular to that line that passes through the point. (There are quick formulas for this but I do not remember them) the line in slope intercept form: 2 y = 2 x + 3 m = 2/2 = 1 so slope of out perpendicular is -1/1 = -1 so y = - x + b goes through (-4,-4) -4...
*March 15, 2014*

**Linear Algebra**

1 4 0
*March 15, 2014*

**Linear Algebra**

1 4 2 17 3 1 -5 7 2 -3 -7 -10
*March 15, 2014*

**Linear Algebra**

http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
*March 15, 2014*

**Probability**

prob first one walked, second did not = (18/50) (32/49) = .235 prob second one walked, first did not is the same so .235 * 2 = .47
*March 15, 2014*

**Probability**

18 of the 50 walked probability that the first one walked = 18/50 now you pick a second out of a population of 49 of whom 17 walked so 18/50 * 17/49 = 306/2450 = .125
*March 15, 2014*

**I really need help**

You are welcome, good luck :)
*March 15, 2014*

**I really need help**

5 * 7 * 3 =
*March 15, 2014*

**I really need help**

area of one side of pyramid = (1/2)(11)(15) = 82.5 cm^2 so area of 4 sides = 330 cm^2 but we also have the area of the bottom which is 11*11 = 121 cm^2 so total = 451 cm^2
*March 15, 2014*

**I really need help**

anything with straight sides and a pointed top has volume = (1/3)base area * height here base area = pi r^2 = 314.159 so vol = (1/3)(314.159)(6) = 628.31 mm^3
*March 15, 2014*

**Pre-Calculus**

OIC, ok r = sqrt (25 + 144) = sqrt (169 ) = 13 angle in quadrant 4 tan angle below x axis = 12/5 angle below x axis = 67.4 degrees or 360 - 67.4 = 292.6 degrees
*March 15, 2014*

**Huh ??**

usually they are of form: a i +/- b j
*March 15, 2014*

**Pre-Calculus**

e^i theta = cos theta + i sin theta so 9 e^i(3 pi/2) ----------------- 3 e^i(pi/4) = 3 e^i(5 pi/4) = 3 [cos (5 pi/4) + i sin (5 pi/4)] = 3 (-.707) + 3i(-.707) or -(3/2) sqrt 2 - (3/2) i sqrt 2
*March 15, 2014*

**Pre-Calculus**

cos pi/3 = 1/2 sin pi/3 = sqrt 3/2 so x = 3/2 and y = (3/2)sqrt 2
*March 15, 2014*

**Pre Calculus**

2 e^i(pi/6) * 4 e^i(4pi/6) = 8 e^i(5 pi/6) = 8 [cos (5 pi/6) + i sin (5 pi/6)] 150 degrees , quadrant 2 , 30 above -x axis 8 [ -sqrt3/2) + i (1/2) ] -4 sqrt 3 + 4 i
*March 15, 2014*

**Physics**

well, you must have found the east and south speeds to get the angle from tan angle = speed south/speed east then Vf = sqrt (Vsouth^2 + Veast^2)
*March 15, 2014*

**Money**

No, but I could 86/102 = x/100 x = 100 (86/102)
*March 14, 2014*

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