Tuesday

September 23, 2014

September 23, 2014

Total # Posts: 18,627

**world history**

That is corrct.
*May 1, 2014*

**Physics**

P V = NRT = constant if n and T constant so P1 V1 = P2 V2 if V2 is half V1 then P2 is TWICE P1 difference in pressure from one side of piston to the other = 1 atm which is about 10^5 Pascals or Newtons.m^2 F = P A = 10^5 newtons.m^2 * pi .23^2 / 4
*May 1, 2014*

**Math**

For example (-1,-3/4) (4,-3/4) (4,3) (-1,3)
*May 1, 2014*

**Physic II**

Nothing happens with 100% efficiency
*April 30, 2014*

**Physics ? geometry**

I do not know V, the initial Volume of gas so can not do the problemP V = n R T P dV + V dP = 0 if n R and T do not change P initial = 10^5 Newtons/m^2 ( or Pacals) dV = (24*10^-4) x V = I have no idea. You left this out. dP = 5*9.81/(24*10^-4)
*April 30, 2014*

**physics**

Ke = (1/2) m v^2 + (1/2) I omega^2 v = omega r so omega = v/r Ke = (1/2) m v^2 + (1/2) I v^2/r^2 = m g (.25) (1/2) m v^2 + (1/2) (2/5) m v^2 = .25 m g (7/10) v^2 = .25 * 9.81
*April 30, 2014*

**geometry**

17 * 17 * 1/6 = 48.167 ft^3 1 yd^3 = 3*3*3 = 27 ft^3 48.167 ft^3/27 ft^3/yd^3 = 1.784 yd^3 1.784 yd^3 * $ 40/ yd^3 = $ 71.36 by the way, concrete people refer to a cubic yard as a "yard". They are not likely to send a truck with 1.784 yards, so you will pay for 2 ...
*April 29, 2014*

**English**

A is wrong. you're means "you are" not "your".
*April 29, 2014*

**Calculus Help and Check**

calculate C' = dC/dx at x = 2000 then dC = C' dx dC = C' (4000-2000) C' = 3 - 20 + 40 = 23 dC = 23 (2000) = 46,000
*April 29, 2014*

**Physics**

.6 seconds is quarter period so period = .6*4 = 2.4 s
*April 29, 2014*

**Physics**

(1/2) m Vmax^2 if x = a sin w t v = a w cos wt so Vmax = a w a is amplitude w is circular frequency = 2 pi f so Ke max = (1/2) m (a^2 w^2) = 2 pi^2 m a^2 f^2
*April 29, 2014*

**Math**

Perhaps they want us to assume it is possible. 4 out of the 15 sides are less than 5 so about 4/15 in each roll so in each roll the probability of NOT getting less than 5 is 11/15 so the probability of NEVER getting less than 5 is (11/15)^45 so our answer is 1 - (11/15)^45 ...
*April 29, 2014*

**Math**

The concept of a 15 sided cube startles me. Did you make this question up yourself?
*April 29, 2014*

**social studies 9**

What country?
*April 29, 2014*

**Math**

Hector cash = 450 + 20 t Tim cash = 1200 - 30 t Are you interested in how many weeks until they are equal? If so 1200 - 30 t = 450 + 20 t 50 t = 1200-450 t = 15 weeks
*April 29, 2014*

**Physics**

(1/2) m v^2 = potential energy potential energy is mgh for low altitude but that will not work for high altitude where g is less than 9.81 m/s^2 increase in potential = G M m (1/Re - 1/(Re+h) call z = Re +h (1/2) v^2 = G M (1/Re - 1/z) solve for z then h = z - Re
*April 29, 2014*

**Physics**

v^2/r = 8.26 F/m = local g = G M/r^2 = 8.26 6.67*10^-11 * Mass earth/r^2 = 8.26 solve that for r then v^2 = 8.26 r solve for v v T = 2 pi r T = 2 pi r/v
*April 29, 2014*

**history**

http://www.ers.usda.gov/data-products/farm-income-and-wealth-statistics/ranking-net-value-and-farm-income.aspx
*April 29, 2014*

**math**

The dimensions are divisible by 6 except 15 so the cubes will fit exactly on the bottom area of 30*18 = 6*6 *15 so 15 cubes covers 30*18 now it can only be 2 cubes high because of the 15 inch height limitation so 15*2 = 30 cubes
*April 29, 2014*

**calculus**

Hey, this is getting a little silly.6x+30 = 6 (x+5) and 3 (x^2-25) = 3 (x+5)(x-5) I think you better forget the calculus and work on basic factoring.
*April 29, 2014*

**calculus**

(x-3) cancels top and bottom
*April 29, 2014*

**calculus**

I am sure you mean (x^2-1)/(5x+5 ) again factor x+1 cancels
*April 29, 2014*

**Information Literacy**

Building Design 27 July 2012 Note: It is real: http://www.bdonline.co.uk/buildings/london-2012-olympic-park/5040360.article
*April 29, 2014*

**Algebra**

x^2 + (x+4)^2 = 18^2 = 324 2 x^2 + 8 x + 16 = 324 2 x^2 + 8 x - 308 = 0 x^2 + 4 x -154 = 0 x = [ -4 +/- sqrt (16 + 616)]/2 = [-4 +/- 2 sqrt 158 ] /2 = -2 +/- sqrt 158 use + root 10.57 14.57
*April 29, 2014*

**maths**

I do not know any trick, sorry 9.45 * 10^12
*April 29, 2014*

**physics**

m g = 1500* 9.81 m g sin theta = 1500 * 9.81 * sin 2 = 514 N propulsive force Power = force * speed = 514 N * 20 m/s = 10.27 KW
*April 29, 2014*

**precalc**

arrgh, English units :( r = (11/12) ft 2 pi r = 5.76 ft/revolution 600 revolutions/min * 60 min/hr =36,000 rev/hr 36,000 rev/hr * 5.76 ft/rev = 207,360 ft/hr 207,360 ft/hr * 1 mile/5280 ft = 39.3 miles/hr
*April 29, 2014*

**precalc**

45 * 2 pi radians/min = omega v = omega r v = 45*2 pi * 16
*April 29, 2014*

**precalc**

(35 +30) * pi/180 radians times r = distance
*April 29, 2014*

**precalc**

Now wait a minute. You can look this up in your text or sketch it out on paper. There is no need to ask me. for example area of sector = (angle/2pi)area of circle I am sure you can do that isoceles triangle in there push down clutch, engage gears :)
*April 29, 2014*

**Math**

5/1.25 = x/6 x = 30/1.25
*April 29, 2014*

**chemistry**

If it is BASIC, it has an H+ concentration LESS than 10^-7 This is an acid !
*April 29, 2014*

**math**

g / (g/hr) ---> hr
*April 29, 2014*

**math**

gallons per hour hours time = total gallons / rate in gallons per hour
*April 29, 2014*

**phisics - no problem/ no copy and paste**

You can not copy and paste here
*April 29, 2014*

**math**

V = pi r^2 h = pi (4)(9) = 113 s^3 = 113 s = 4.84 cm
*April 28, 2014*

**Algebra**

2*2*2 = 8
*April 28, 2014*

**Algebra**

i = .089/2 = .0445 X = 35,000 (1.0445)^(2t)
*April 28, 2014*

**College Algebra**

w = c L^3 w = c [512] [ (1-e^-t)^3 ] = 512 c ----------- aside multiplication problem (1-e^-t)^3 = (1-e^-t)(1 - 2e^-t +e^-2t) =1(1 - 2e^-t +e^-2t) -e^-t(1 - 2e^-t +e^-2t) = 1 - 2e^-t +e^-2t -e^-t +2e^-2t -e^-3t = 1 -3e^-t +3e^-2t -e^-3t ------------------ w = 512 c [1 -3e^-t +...
*April 28, 2014*

**MATH 12**

4 s h + s^2 = 12 so h = (12-s^2)/4s v = s^2 h v = s^2 (12-s^2)/4s = (12 s^2 -s^4)/4s v = 3 s -(1/4) s^3 dv/ds = 0 for max = 3 - (3/4) s^2 (3/4) s^2 = 3 s^2 = 4 s = 2 h = (12 - 4)/8 = 1
*April 28, 2014*

**physics**

V = 60 volts d = .03 meters E = 60/.03 = 2000
*April 28, 2014*

**physics**

no I do not know what question 4 is but divide the voltage by .03 meters to get E in a capacitor E = volts/ distance
*April 28, 2014*

**physics**

d = .03 meters E = V/d
*April 28, 2014*

**physics**

voltage is potential energy per unit charge. because The force on a charged particle in an electric field is q E between the plates of your capacitor E= V/d so the work done on the charge = Force * distance = q E d = = q V so 5*10^-4*60 = 300 *10^-4 = 3*10^-2 or .03J
*April 28, 2014*

**physics**

.1 Joules = 2*10^-6 V V = .1 * 10^6 /2 = .05*10^6 = 5*10^4 = 50,000 volts Yes :) and yes, volts is Joules per coulomb
*April 28, 2014*

**physics**

same thing again and again Volts is potential energy PER UNIT charge That is why they call Volts electric potential change in potential energy = charge * volts !!!
*April 28, 2014*

**physics**

Hey, this is the first problem I did for you backwards.
*April 28, 2014*

**physics**

Yes !!! :)
*April 28, 2014*

**physics**

Amanda, all your questions are answered by Voltage = potential energy per unit charge
*April 28, 2014*

**physics**

E q = Force (Newtons) { like m g ) so E q d = work (Joules) = increase in potential energy (like m g h) so E d = increase in potential energy per unit charge which we call V, voltage or electric potential (per Coulomb implied). like g h (increase in potential energy per unit ...
*April 28, 2014*

**physics**

Yes, m g h is joules in gravitational acceleration g E q = Force (Newtons) so E q d = work (Joules) = increase in potential energy so E d = increase in potential energy per unit charge which we call V, voltage or electric potential (per Coulomb implied).
*April 28, 2014*

**physics**

That is 30 Joules
*April 28, 2014*

**TYPO 60 not 90**

Yes, 60 volts * .5 coulombs = change in potential energy
*April 28, 2014*

**physics**

Yes, 90 volts * .5 coulombs = change in potential energy
*April 28, 2014*

**physics**

I am going to scream! Voltage = change in potential per unit charge. change in potential energy = q * change in V
*April 28, 2014*

**Help- Math**

You are welcome.
*April 28, 2014*

**Help- Math**

F = k/d^2 b) undefined because zero denominator (gets very big as d gets small) c) If an object has mass, it also has size. It is impossible to get d = 0 because the objects bump before their centers of gravity collide. So, although the force can become large, it does not ...
*April 28, 2014*

**Math-Help**

max profit is at 250 so if spending more than that, spend less
*April 28, 2014*

**Math-Help**

5000 = 1+ 50 a -.1 a^2 .1 a^2 - 50 a - 1 = -5000 .1 a^2 - 50 a + 4999 = 0 solve quadratic roots are 250+/-3sqrt1390 250 +/- 112 so 362 or 138
*April 28, 2014*

**Math-Help**

a) where is the vertex? .1 a^2 - 50 a -1 = -p a^2 -500 a -10 = -10 p a^2 - 500 a = -10 p + 10 a^2 - 500 a + 250^2 = -10 p + 62510 (a-250)^2 = -10 (p-6251 so max profit of 6251 at a = 250
*April 28, 2014*

**Math-Help**

No one, like no one, uses feet any more for physics problems but anyway It is a parabola (uppside down, sheds water) c) at t = 0, h = 5,1 d) find the vertex by completing the square or know that the rock is at the top when the velocity is zero which is when -32 t + 100.4 = 0 t...
*April 28, 2014*

**Science**

I is Iodine Cl is Chlorine
*April 28, 2014*

**math**

(1 dollar/16 oz)(40 oz/can)(18 cans) = $45
*April 28, 2014*

**Science**

NH4 +1 and Cl -1 and Na1+1 and OH1-1 are all ions
*April 28, 2014*

**physics**

.45 WHAT? millimeters, meters? pounds ? m/s^2 ? Newtons? Moreover, what is the question? Did you make it up or copy it incorrectly from somewhere?
*April 28, 2014*

**physics**

vetical speed = sqrt (2 g h) = sqrt (232) =15.2 m/s speed = sqrt (15.2^2 + 5.3^2)
*April 28, 2014*

**Math**

7! = 5040 if the two oldest are one, then we only really have six 6! = 720 but one could be right and the other left or reverse so twice that many *2 = 1440
*April 28, 2014*

**biology**

First, the vegetation takes in CO2 and uses it through photosynthesis to make vegetation and release O2. It also prevents runoff of the soil in gigantic floods by absorbing rainfall, protects all sorts of wildlife and flora that does not exist elsewhere, and grows many useful ...
*April 28, 2014*

**biology**

Oh my heavens, best Google that
*April 28, 2014*

**biology**

One might send the residents free firewood or solar panels and stop drinking coffee and stop the out of control growth of the human population.
*April 28, 2014*

**math**

(3b+2) / (9b+6) = 1(3b+2)/3*(3b+2) = 1/3 so the length is one third of the width :)
*April 28, 2014*

**biology**

More CO2 and less O2 in atmosphere (greenhouse effect) Loss of biodiversity (species go extinct even before we even knew their blood cured cancer or whatever.)
*April 28, 2014*

**Algebra 2**

twelve draw tree branches or do 3*2*2
*April 28, 2014*

**algebra2**

She gets four raises 30,000 (1 +1.02 +1.02^2 +1.02^3+1.02^4) You could just calculate that out or do it as a geometric sequence.
*April 28, 2014*

**Physics**

r = .039875*10^6 +1.74*10^6 = 1.78*10^6 G = 6.67*10^-11 M = 7.35*10^22 F = m v^2/r G M m /r^2 = m v^2/r v^2 = G M /r T^2 = (2pi)^2 * r^2/v^2 T^2 = (2pi)^2 * r^3 /GM T^2 = 39.5*5.64*10^18/(6.67*10^-11*7.35*10^22) T^2 = 4.54 * 10^7 = 45.4 * 10^6 T = 6.74 * 10^3 = 6740 seconds (...
*April 28, 2014*

**Physics**

Take a good look at the one I just did for help please. The numbers are different but the problem uses the same logic, primarily: T^2 = (2pi)^2 * r^3 /GM ------------------------------------ r = .039875*10^6 +1.74*10^6 = 1.78*10^6 G = 6.67*10^-11 M = 7.35*10^22 F = m v^2/r G M...
*April 28, 2014*

**Physics MCQ - Quick check**

You are welcome :)
*April 28, 2014*

**Physics MCQ - Quick check**

tan theta = sqrt 3/1 theta = 60 deg = pi/3 right
*April 28, 2014*

**Physics MCQ - Quick check**

A cube of mass 2.0 kg is kept pressed against a vertical wall by applying a horizontal force of 60N. If the coefficient of friction between the cube and the wall is 0.50, the frictional force between the cube and the wall is ? 19.6 N ---------------------------- If the cube is...
*April 28, 2014*

**Physics MCQ - Quick check**

Ac = v^2/R = c = 2 pi R Hey, you need to go faster, not slower ! T = c/v = 2 pi R/v so v^2 = (2 pi R)^2/T^2 v^2/R = {(2pi)^2/R T^2] 3 v^2/R = {(2pi)^2/R T^2] *3 so 3/T^2 = 1/T'^2 3 T'^2 = T^2 T'^2 = T^2/3 T' = T /sqrt 3
*April 28, 2014*

**Engineering Physics**

This is comparable to the position derivatives where: velocity = dx/dt and acceleration = d^2x/dt^2
*April 28, 2014*

**Engineering Physics**

omega = angular VELOCITY = d Theta/ dt alpha = angular ACCELERATION = d^2Theta/dt^2 Therefore b)
*April 28, 2014*

**physics**

I answered this before but the question disappeared Heat out of steam= 20 {2260+4.2(100-T)} Heat into water = 80 (T-20) so 4(T-20) = 2260 + 4.2(100-T) 4 T - 80 = 2260 + 4200 - 4.2 T 8.2 T = 6540 T = 797 which is silly of course What it means is that 80 grams of water at 20 ...
*April 27, 2014*

**math**

first pie cost 6 * 20 = 120 cents second pie cost 8 * 30 = 240 cents it doubled which is an increase of 100 % [ (240 -120)/120 ] * 100 = 100%
*April 27, 2014*

**Algebra 1**

This is Algebra 1 where ?
*April 27, 2014*

**Algebra 1**

1 agree https://hrdag.org/convenience-samples-what-they-are/ 2 agree http://en.wikipedia.org/wiki/Sampling_%28statistics%29#Systematic_sampling
*April 27, 2014*

**Maths**

You need five if you have no typos. Draw it on a piece of paper. to use math: tile area = 1/6*1/6 = 1/36 rectangle area = 1/6 * 5/6 = 5/36 5/36 / 1/36 = 5
*April 27, 2014*

**Maths**

Unless you have a typo (which I suspect), five of them in a row would cover it.
*April 27, 2014*

**Math**

I am taking the easy way out: http://www.cs.virginia.edu/~lat7h/blog/posts/219.html
*April 27, 2014*

**Algebra 1**

If that is Algebra 1, you are at a good school :)
*April 27, 2014*

**Algebra 1**

1 Yes (I had to think for a minute:) 2 Yes 3 Yes
*April 27, 2014*

**algebra**

2+3 = 5 so 2/5 and 3/5 2/5 = 10/25 3/5 = 15/25 check: 10 + 15 = 25 yes 10/15 = 2/3 check :)
*April 27, 2014*

**Disappearing questions now ?????**

There was another question in here that seems to have disappeared but my answer remained ?
*April 27, 2014*

**physics**

Heat out of steam= 20 {2260+4.2(100-T)} Heat into water = 80 (T-20) so 4(T-20) = 2260 + 4.2(100-T) 4 T - 80 = 2260 + 4200 - 4.2 T 8.2 T = 6540 T = 797 which is silly of course What it means is that 80 grams of water at 20 degrees simply can not condense 20 grams of steam. The ...
*April 27, 2014*

**physics**

Yes, it is just the ratio of heat of vaporization to heat of fusion. I get 2260 J/gram / 334 J/gram = 6.77 g
*April 27, 2014*

**Linear algebra**

note first that if a = 1, the first and third rows are identical (infinite number of solutions) then calculate the determinant of the coefficient matrix. Find its zeros. One will be a = 0 Look at second equation when a = 0, x+y = 0 and first equation gives x+y = 0 and third ...
*April 27, 2014*

**math**

9 x^2 - 2 x - 4 = 0 x= [ 2 +/- sqrt (4 + 144 ) ] / 18 x = [ 2 +/- 12.2 ] /18 it says approximate so I will say 12.2 = 12 x = 14/18 or -10/18 or x = .8 or -.6
*April 27, 2014*

**physics**

Hey look, Bob Pursley told you how to do these heat gained/ heat lost problems. You keep posting basically the same problem over and over. You are supposed to learn how to do them. Try. Post your attempts.
*April 27, 2014*

**Physics**

south momentum = 1900 * 13.6 = 25840 east momentum = 3854 * 9.8 = 37769 same after of course mass = 1900+3854 = 5754 south momentum = 5754 Vs = 25840 Vs = 4.49 m/s east momentum = 5754 Ve = 37769 Ve = 6.56 m/s V = sqrt (Vs^2+Ve^2) = 7.95 m/s tan angle E of S = Ve/Vs = 6.56/4....
*April 26, 2014*

**Precalculus**

To be in A intersect B, a number must be both prime and a factor of 36 factors of 36 less than 16: 1 3 4 6 9 12 of those only 1 and 3 are prime unite those with the multiples of 4 which are 4 8 12 and you get 1 3 4 8 12
*April 26, 2014*

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