Thursday

October 30, 2014

October 30, 2014

Total # Posts: 19,067

**physics**

How much energy should it have? m g h = 1.6 * 9.81 * 2.9 How much does it have? (1/2) m v^2 = (1/2) * 1.6 * (2.8)^2 so subtract
*June 9, 2014*

**math study guide**

1. no idea, do not have data 2. I get 8/20 = .40 3. again no data but in theory 3/4 4. 15/100 = 3/20 5. 20/100 = x/50 ??? Hey, are you just guessing or what?
*June 6, 2014*

**Science**

You are welcome.
*June 6, 2014*

**Science**

a) yes b) yes c) yes d) yes, traveling wave, air particles moving
*June 6, 2014*

**Math**

19 marbles p(first is purple) = 2/19 now 18 marbles, what is p(yellow) first p(yellow) = 5/18 so p(NOT yellow) = 13/18 p purple then not yellow) = 2/19 * 13/18
*June 6, 2014*

**Math**

p(not 5) = 5/6 then p(green) = 1/6 so 5/6 * 1/6 = 5/36
*June 6, 2014*

**Math**

Permutations of 7 items taken 3 at a time. The order matters so it is permutations, not combinations. Look at "ordered subsets" in the link: http://dwb4.unl.edu/Chem/CHEM869N/CHEM869NMats/Permutations.html 7! / (7-3)! = 7!/4! = 7*6*5 = 210
*June 6, 2014*

**Math**

There are four possible results A. Mike and Dave both miss B. Mike hit, Dave miss C. Dave hit, Mike miss D. both hit p mike hits = .6 so misses = .4 p dave hits = .3 so misses = .7 So p(A) = .4 * .7 p(B) = .6 * .7 p(C) = .3 * .4 p(D) = .6 * .3 We want p(A) + p(D) = .28 + .18...
*June 6, 2014*

**Math**

say 8/64 are red then probability of two red is 8/64 * 7/63 = 1/8 * 7/63 the next one is yellow, again same answer but now twice the probability so in the end 8 * 1/8 * 7/63 = 7/63
*June 6, 2014*

**Science**

or yes, yes :)
*June 6, 2014*

**Science**

35 * g = weight weight * distance raised = work in which is exactly the increase in potential energy
*June 6, 2014*

**Algebra ll**

You are welcome.
*June 6, 2014*

**Algebra ll**

(x - a)^2 + (y-b)^2 = r^2 for circle of radius r and center at (a,b)
*June 6, 2014*

**Math**

This is more fun every hour! Four ways now :)
*June 6, 2014*

**Math**

LOL !!!
*June 6, 2014*

**Math**

sketch a graph first If it goes through (0,4) and (2,4) I suspect that the center is on the line x = 1 (x-1)^2 + (y-b)^2 = r^2 when x = 0, y = 4 1 + (4-b)^2 = r^2 when x = 2, y = 4 1 + (4-b)^2 = r^2 again of course when x = -5, y = 0 36 + b^2 = r^2 so 1 +(4-b)^2 = b^2+36 1 + ...
*June 6, 2014*

**Science**

8.b yes 9.c Huh? 21/21 = 1 10.a I do not think so. She, not the wheelbarrow, supplied the work. If it weighed 35 N and she lifted it 2.5 meters, then D would be correct. The problem is poorly written. It is not clear if the force is in the direction of motion.
*June 6, 2014*

**physics**

PE = - G m Me/R where G = 6.67 * 10^-11 Look at change in potential energy at R = 6.38*10^6 and at 6.38*10^6 + .120 *10^6 meters I bet it would not be far off to use m g h where g = 9.81 m/s^2 :) because 120 km is not far compared to Rearth
*June 6, 2014*

**calc**

draw a sketch If the interval means from x = -1 to x = +2, then it is also from y = 2 to y = 8 As I read it then this base is a triangle with corners at (-1,8) (2,2) and (-1,2) The volume of the figure would then be 2 times the area of the base Area of base = (1/2) (3)(6) = 9 ...
*June 6, 2014*

**pre calc**

(x+5)^2 = 4 (y + 1/2) vertex at (-5, -1/2) so for the left half x is always less than (to the left of) -5 an y is above -1/2 I do not know what else to say
*June 6, 2014*

**physics**

F = m g = G M m /r^2 so g = G M/R^2 double m, double g double R , divide by 4 so 15.5 / 2
*June 6, 2014*

**Chemistry**

In a liter you have .1 mol of HCl .1 * (35.5 + 1) = 3.65 grams/liter so in half a liter you have 1.825 grams of HCl
*June 6, 2014*

**Math**

2(117) - 1 is not 2001
*June 6, 2014*

**Math**

1, 3 , 5 , 7 , 9 ....... first is 1 = 2 - 1 second is 3 = 4 - 1 third is 5 = 6 - 1 number (n) = 2 n - 1 number (117) = 2(117) - 1
*June 6, 2014*

**MULTIPLY. WRITE EACH PRODUCT IN SCIENTIFIC NOTATIO**

a^x * a^y = a(x+y) a^x / a^y = a^x * a^-y = a^(x-y)
*June 6, 2014*

**algebra**

-6x^2 + 7 x just to be sure you followed all that
*June 6, 2014*

**physics**

Fx * x = 40 cos 28 * 100 foot pounds
*June 6, 2014*

**Math**

p(not red) = 1 - p(red)
*June 6, 2014*

**Calculus**

2 W + L = 40 so L = 40 - 2 W A = W L = W (40 - 2 W) = 40 W - 2 W^2 dA/dW = 40 - 4 W W = 10 so yes
*June 6, 2014*

**mathematics**

dy/dx = 6 x^2 + 15 x^4 then y = 2 x^3 + 3 x^5 + c find c 7 = 2(8) + 3(32) + c 7 = 16 + 96 + c c = -105 so y = 2 x^3 + 3 x^5 - 105
*June 6, 2014*

**Calculus**

A = x^2 = (3t+1)^2 = 9 t^2 + 6 t + 1 dA/dt = 18 t + 6 when t = 2 dA/dt = 36 + 6 = 42
*June 6, 2014*

**algebra**

excuse me, typo like 2^2 * 2^3 = 2^5 = 32 which is also 4*8
*June 6, 2014*

**algebra**

x^(9-2) = x^7 because x^a * x^b = x^(a+b) like 2^2 * x^3 = 2^5 = 32 which is also 4*8
*June 6, 2014*

**physics**

680C = 273+680 = 953 K 220 C = 273 + 220 = 493 K e = (953-493)/953 = .483 IF and ONLY IF it is a Carnot cycle heat engine (maximum efficiency)
*June 6, 2014*

**math**

36/60 = 6/10 = 3/5
*June 5, 2014*

**science pls help asap!!!**

the A horizon is topsoil wind removes topsoil mostly by abrasion loess is soil settled from the wind often in the lee of an obstacle. I am not sure dunes need an obstacle.
*June 5, 2014*

**math**

A) correlation coefficient is between -1 and +1 , not 1.09 B) negative coefficient means that y is pretty well correlated with negative x. It is pretty much a straight line but with negative slope. like y = -5x + 3 http://www.dmstat1.com/res/TheCorrelationCoefficientDefined.html
*June 5, 2014*

**math**

You got three even numbers (4 , 2 and 6) out of eight tosses.
*June 5, 2014*

**math**

5! 120
*June 5, 2014*

**math**

4*6*3 = ?
*June 5, 2014*

**Physics**

Fx dx + Fy dy (-3 * 3.6) - (7.6 * -2) 4.4
*June 5, 2014*

**algebra**

You are welcome.
*June 5, 2014*

**algebra**

I did. It is not a straight line. answer is no
*June 5, 2014*

**algebra**

what is (25-17)/(2-1) ? 8 what is (1 - -7) /( -1 - -2) ? 8/1 = 8 humm looks like slope = 8 so far but what about (17 -8)/ (1 - 0) = 9 !!!!! oh my, not the same slope crash not on a straight line of constant slope
*June 5, 2014*

**algebra**

Oh ! 5*3^1 = 15 5*3^2 = 5*9 = 45 45* 3 = 135 135 * 3 = 405
*June 5, 2014*

**algebra**

nor do I unless you have a value for n
*June 5, 2014*

**algebra**

You are welcome :)
*June 5, 2014*

**algebra**

If x = 2 2 * 1^2 = 2*1 = 2
*June 5, 2014*

**Science**

Hey, in orbit there is no air around you and therefore no air pressure. You must maintain approximately atmospheric pressure inside if manned. If unmanned, you still must make sure nothing blows up when the outside pressure goes to zero. There is no nice layer of air to ...
*June 5, 2014*

**Science**

It sounds like you might have proposed a space mission as a class project or something and the question is asking why it should be funded and how it would work with other efforts.
*June 5, 2014*

**Science**

1200 * 15 Joules 2500 * 16 Joules work = Force component in direction of motion * distance moved. I wonder why you are asking. This should be in the first sentence of the first paragraph of your text on the subject.
*June 5, 2014*

**science 1 question!!!**

Number 1 is really an English comprehension question. Rivers generally run down valleys. therefore I am at a loss to understand why a valley glacier would spread out over a continent while a continental glacier would stick to a spot in the mountains.
*June 5, 2014*

**science**

Potential energy gain = m g h where h is the distance lifted
*June 5, 2014*

**physics**

I assume you mean in a centrifuge? If so Ac = v^2/R so g = v^2/R v = sqrt ( R g) = sqrt (9.81 R)
*June 5, 2014*

**Physics**

The loudness is the amount of power passing through a square meter of area surrounding the source. As you get further from a constant power source, the loudness decreases because the area of a sphere surrounding the source increases. ( You know that. As you get further from a ...
*June 5, 2014*

**physics**

get V from momentum (75 + 52) V = 75 (1.8) calculate V calculate (1/2) m V^2 friction force = .042 * m * g friction force * distance = (1/2) m V^2 or actually m cancels .042 g d = .5 V^2
*June 4, 2014*

**physics**

(1/2) m v^2 = (1/2) k x^2
*June 4, 2014*

**physics**

Hey, you have done several of these now. Try
*June 4, 2014*

**Math**

cost per unit = cpu = C(x) / x = 36,100/x + 100 +.01 x d cpu/dx = 0 at min = -36,100/x^2 + .01 .01 x^2 = 36,100 x^2 = 3,610,000 x = 1900 units now go back and get cpu = 36,100/1900 + 100 + .01(1900) = 2019
*June 4, 2014*

**Math**

2 dimensional with 3 or more sides side angle
*June 4, 2014*

**Physics**

k = 30 N/.2 m = 150 N/m PE of spring = (1/2) k x^2 = 75(.04)=3 Joules normal force = m g friction force = .4 m g work done against friction = .2 *.4 * mg = .08*.25*9.81 = .196 Joules so Ke left = 3 - .196 = 2.8 Joules (1/2) m v^2 = 2.8 calculate v
*June 4, 2014*

**Precalculus**

6 letters if start with A so 5 left c(5,3) = 10 10 more start with I so 20 total others similar
*June 4, 2014*

**Precalculus**

2a 9*10*10 = 900 2b 4 * 5 * 5 2c 9 * 1 * 10
*June 4, 2014*

**Precalculus**

c(20,5) = 20!/(5!*15!) = 20*19*18*17*16 /(5*4*3*2) = 15504
*June 4, 2014*

**Precalculus**

1. NO The order does not matter, Disney first or white mountains first so COMBINATION C(20,5)
*June 4, 2014*

**Math**

x = 15 - 2y x^2 = 225 - 60 y + 4 y^2 F = 5 y^2 -60 y + 225 dF/dy = 10 y - 60 zero when y = 6 then x = 3 is that min or max? d^2F/dy^2 = 10 so it is min F here = 9+36 = 45 check ends if x = 0 y = 7.5 and F = 56 1/4 if y = 0, x=15 and F = 225 ok, done
*June 4, 2014*

**Math - Business Calc.**

Hey, use that h, calculate L and w find L W h
*June 4, 2014*

**Math - Business Calc.**

L = 17 - 2 h W = 5 - 2 h V = L W h V = (17-2h)(5-2h)h = (17-h)(5h-2h^2) dV/dh = (17-h)(5 - 4h) +(5h-2h^2)(-1) = 85 - 73 h +4 h^2 -5h + 2 h^2 = 85 - 78 h + 6 h^2 where is that derivative zero? h = [ 78 +/- sqrt (6084-2040) ]/12 h = [ 78 +/- 63.6 ] / 12 h = 11.7 impossible, ...
*June 4, 2014*

**physics**

hey, just like the last one ! PE = (1/2) k x^2 PE = m g h = m g d sin 30 = .5 m g d if d is distance along the ramp
*June 4, 2014*

**Math**

sum of degrees of exterior right turns = 360 (all the way around) 360/5 = 72 so each interior angle is 180 - 72 = 108 and 5*108 = 540
*June 4, 2014*

**physics**

loss of potential energy by ball = m g (1.5 + x) gain of potential energy by spring = (1/2)(150)x^2 so 2.2 * 9.81 *(1.5+x) = 75 x^2 21.6 x + 32.4 = 75 x^2 or 75 x^2 - 21.6 x - 32.4 = 0 x = [21.6 +/-sqrt(467+9720) ]/150 x = [ 21.6 + 101 ] /150 x = .817 meter
*June 4, 2014*

**physics**

F = .15 * 45 a = F/m
*June 4, 2014*

**Physics**

first ball stops in 2.3/2 = 1.15 seconds 0 = Vi - g t Vi = 9.81 (1.15) = 11.3 m/s second ball has same Vi Vi = V sin 42 V = 11.3/sin 32 = 21.3 m/s
*June 4, 2014*

**MATH PLZ HELP**

one every 15 minutes is 4 per hour
*June 4, 2014*

**Physics**

0 = 0 + Vi t - 4.9 t^2 Vi = 9.95 sin 35 = 5.71 so 0 = 5.71 t - 4.9 t^2 t = 0 or t = 1.16 t = 0 was zero height when it started t = 1.16 seconds is zero height when it landed
*June 4, 2014*

**Physics**

That is how much negative charge it is missing. (How much positive charge it has)
*June 4, 2014*

**Physics**

F = q E = m a E = m a/q m is given q = 5*10^3 * electron charge a is given
*June 4, 2014*

**Physics**

(2L/3)(3W)(3H)
*June 4, 2014*

**civics**

I do not know. What is the correct C?
*June 4, 2014*

**typo**

You B and C are the same and you left out the right choice.
*June 4, 2014*

**science**

This is oversimplified. Yes, you need data, but you also need a mathematical model and theory.
*June 4, 2014*

**History**

Oligarchy means government by a select few. Therefore I would say B. However it is not necessarily a political party. It could be just a group of rich people or guys with guns.
*June 4, 2014*

**physics**

normal force = 55 g friction force = .11 * 55 g acceleration = F/m = -.11 * 55 * g /55 = -.11 g = -1.08 m/s^2 v = Vi + a t 0 = 5.6 - 1.08 t t = 5.2 seconds to stop go at average speed (5.6 /2) for 5.2 seconds d = 14.5 meters
*June 4, 2014*

**Delcambre High**

(4/15) / (1/3) multiply top and bottom by 15 4 / 5
*June 4, 2014*

**civics**

Mexicans often migrate North to get jobs. Of course Texas and half of California and Arizona and New Mexico ... were Mexico.
*June 4, 2014*

**civics**

Halifax, Quebec, Montreal Ottawa, Toronto --- Vancouver Which are in the North of Canada on the Arctic Ocean ?
*June 4, 2014*

**civics**

It certainly is NOT A !!!! Hey, take a good look at where cities are in Canada Come on, why do Mexicans move North ? Is New York or Chicago or Montreal or Toronto subtropical or tropical ?
*June 4, 2014*

**math**

now wait a minute, time to learn this stuff: In a right triangle: sin theta = opposite / hypotenuse cos theta = adjacent / hypotenuse tan theta = opposite / adjacent so here we have hypotenuse is ladder, 13 adjacent = along ground = 3.7 so cos theta = 3.7/13
*June 4, 2014*

**math**

tan theta = 5.5 / d
*June 4, 2014*

**civics**

By the way, cost on a ship for freight is much less per mile than by any other method.
*June 4, 2014*

**civics**

That would be my answer, but you could disagree if you say why :) I see oceans at the borders, not rivers or lakes for the most part (except the Rio Grande and some Great Lakes of course)
*June 4, 2014*

**civics**

Well, from Halifax to San Diego, North America abounds in seaports on the Atlantic and Pacific although Mexico has relatively small ones.
*June 4, 2014*

**Math**

total length = 20 + 10 = 30 total width = 10 + 10 = 20 so total area = 600 but area of photo itself = 20*10 = 200 so frame area = 400 400/600 * 100 = 67 % is frame
*June 4, 2014*

**chemistry**

PV = n R T = constant so P1 V1 = P2 V2 565 (235) = P2 (215)
*June 4, 2014*

**physics**

We do not know yet if the top block slips. First, assume it does not slip. F = m a 30 = (4+2) a a = 5 m/s^2 Now How much force is required to accelerate the top block at 5 m/s^2? F = 2 (5) = 10 N required How much do we have? Fnormal = m g = 2*9.81 = 19.62 N so friction max...
*June 4, 2014*

**statistics**

http://davidmlane.com/hyperstat/z_table.html here z = (.62 - .60) / .02 = 1
*June 4, 2014*

**Math**

(p q)^3 ( q + p q^2) 3^3 ( q + 3 q) 3^3 (4q) 27 (4 q) 108 q
*June 4, 2014*

**Math**

total marbles = 6 + 10 + 9 = 25 first draw 9/25 second draw 8/24 so (9/25)(1/3) = 9/75
*June 4, 2014*

**science**

v= 3^3 = 27 cm^3 rho = m/v = 54/27 = 2 grams/cubic centimeter
*June 4, 2014*

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