Friday

August 1, 2014

August 1, 2014

Total # Posts: 17,591

**Constituion**

All of it.

**Chemistry**

.25 (100/65)

**Calculus Help Please Urgent!!!**

Oh, I take that back, their function includes the proper period and amplitude.

**Calculus Help Please Urgent!!!**

Hey, I just gave you the method, not the answer You have to put in the given period and amplitude

**Calculus Help Please Urgent!!!**

dV/dt = f(t) = (3/10) sin (2 pi t/3) V = integral of that dt = -(3/10)(3/2pi) cos (2 pi t/3) = -(9/20pi)cos (2 pi t /3)

**Chemistry**

I also typed it wrong 4.184 not 4,184

**Chemistry**

Specific heat water - 4.187 kJ/kgK = 4,187 J/gC

**Chemistry**

change of water temp = +2 deg C heat energy into water = Cwater*m *2 deg heat energy out of rock = 532.1 J so 531 J = Cwater * m * 2 Cwater is specific heat of water in Joules/(gram deg C)

**science**

carbon credits? http://en.wikipedia.org/wiki/Carbon_credit

**Physics**

Now think! Did the mass of the sphere change? Was it a nuclear reaction? What dos the fluid pressure have to do with good old Archimedes? How long would the temperature of the sphere and the fluid stay different? LOL How did the volume inside the sphere change if the glass did...

**Pysical science**

.05 kg = 50 grams 50 g / 7.9 g/cm^3 = (50/7.9) cm^3

**Physics quick help please**

Voltage * charge = work done by E field on charge Same thing really Volts = E * d Use METERS volts, Coulombs

**PHYSICS URGENT**

Volts + charge = work done If + charge moves in direction of E field, potential goes down .02 meters E = V/d

**algebra**

sure (5) /2 = 2 Remainder 1 which is exactly the same as 2 1/2 That is really what "remainder means" .

**world history**

That is corrct.

**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

**Math**

For example (-1,-3/4) (4,-3/4) (4,3) (-1,3)

**Physic II**

Nothing happens with 100% efficiency

**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)

**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

**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 yar...

**English**

A is wrong. you're means "you are" not "your".

**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

**Physics**

.6 seconds is quarter period so period = .6*4 = 2.4 s

**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

**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 whi...

**Math**

The concept of a 15 sided cube startles me. Did you make this question up yourself?

**social studies 9**

What country?

**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

**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

**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

**history**

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

**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

**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.

**calculus**

(x-3) cancels top and bottom

**calculus**

I am sure you mean (x^2-1)/(5x+5 ) again factor x+1 cancels

**Information Literacy**

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

**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

**maths**

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

**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

**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

**precalc**

45 * 2 pi radians/min = omega v = omega r v = 45*2 pi * 16

**precalc**

(35 +30) * pi/180 radians times r = distance

**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 :)

**Math**

5/1.25 = x/6 x = 30/1.25

**chemistry**

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

**math**

g / (g/hr) ---> hr

**math**

gallons per hour hours time = total gallons / rate in gallons per hour

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

You can not copy and paste here

**math**

V = pi r^2 h = pi (4)(9) = 113 s^3 = 113 s = 4.84 cm

**Algebra**

2*2*2 = 8

**Algebra**

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

**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 +...

**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

**physics**

V = 60 volts d = .03 meters E = 60/.03 = 2000

**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

**physics**

d = .03 meters E = V/d

**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

**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

**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 !!!

**physics**

Hey, this is the first problem I did for you backwards.

**physics**

Yes !!! :)

**physics**

Amanda, all your questions are answered by Voltage = potential energy per unit charge

**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 m...

**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).

**physics**

That is 30 Joules

**TYPO 60 not 90**

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

**physics**

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

**physics**

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

**Help- Math**

You are welcome.

**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 real...

**Math-Help**

max profit is at 250 so if spending more than that, spend less

**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

**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

**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...

**Science**

I is Iodine Cl is Chlorine

**math**

(1 dollar/16 oz)(40 oz/can)(18 cans) = $45

**Science**

NH4 +1 and Cl -1 and Na1+1 and OH1-1 are all ions

**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?

**physics**

vetical speed = sqrt (2 g h) = sqrt (232) =15.2 m/s speed = sqrt (15.2^2 + 5.3^2)

**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

**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 ...

**biology**

Oh my heavens, best Google that

**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.

**math**

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

**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.)

**Algebra 2**

twelve draw tree branches or do 3*2*2

**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.

**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 (a...

**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...

**Physics MCQ - Quick check**

You are welcome :)

**Physics MCQ - Quick check**

tan theta = sqrt 3/1 theta = 60 deg = pi/3 right

**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...

**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

**Engineering Physics**

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

**Engineering Physics**

omega = angular VELOCITY = d Theta/ dt alpha = angular ACCELERATION = d^2Theta/dt^2 Therefore b)

**physics**

How can I tell you if you do not tell me h, the height of the building? For heavens sake look up the height of the empire state building in meters and do the problem.

**physics**

rho g Hg = 12.65 * h Pascals I left the h out of this line

**physics**

I did not know how many meters tall the building was yesterday or today :) decrease in air pressure = rho g h = 1.29 * 9.81 h in Pascals = 12.65 h Pascals if Hg = change in Hg height IN METERS rho g Hg = 12.65 Pascals 13600 *9.81 Hg = 12.65 h Pascals Hg = 9.48*10^-5 h so if I ...

**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 deg...

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