Sunday

December 21, 2014

December 21, 2014

Total # Posts: 19,972

**Physics**

(v+c)19.8 = (v-c)21 and (v+c)19.8 = 208
*September 15, 2014*

**Algebra 2**

5 n + 25 q = 620 25 n + 5 q = 970
*September 15, 2014*

**Statics**

102
*September 15, 2014*

**World History (Ms. Sue)**

Pretty good.
*September 15, 2014*

**Math using quadratic equation**

I suspect typos and there is no quadratic involved as it is stated. v = passenger train speed (v - 12) = freight train speed (v-12)t = 65 v t = 165 so 65/(v-12) = 165/v 65 v = 165 v - 1980 100 v = 1980 v = 19.8 mph v-12 = 7.8
*September 15, 2014*

**Math using Quadratic equation**

s^2 = 196 s = 14 check : 12 * 14 = 196
*September 15, 2014*

**Curriclum**

You are right !
*September 14, 2014*

**math**

-32 - 13
*September 14, 2014*

**physics**

average speed during deceleration = 2.5*10^3 m/s time is then 4 m/2.5*10^3 m/s = 1.6*10^-3 seconds to stop a = - 5*10^3/1.6*10^-3 = -3.125*10^6 m/s^2 = - 3,125,000 m/s^2:)
*September 14, 2014*

**physics**

u = 75 cos 57.3 so t = 21.5 /(75 cos 57.3) Vi = 75 sin 57.3 h = Vi t - 4.9 t^2 answer = h-11
*September 14, 2014*

**Physics**

I just answered this a few minutes ago. I used the rest mass here because .3*.3 is just about .1 and not worth calculating beta. However look at the problem below this one if you want to do the relativistic problem. Posted by Paul on Sunday, September 14, 2014 at 4:30pm. ...
*September 14, 2014*

**Physics**

m at .77 c beta = .77 sqrt (1 - beta^2 )= sqrt(.4071) = .638 so m' = 1/.638 = 1.57 kg (1/2)m' v^2 = 4.19*10^16 Joules
*September 14, 2014*

**Physics**

(1/2) m v^2 = 5,000 * (.3*3*10^8)^2 = 5*10^3 * .81 * 10^16 = 4.05 * 10^19
*September 14, 2014*

**Pre-Calculus**

http://www.mathportal.org/calculators/polynomials-solvers/polynomial-roots-calculator.php
*September 14, 2014*

**math**

L = (3w-5) L w = 782 (3w-5)w = 782 3 w^2 -5 w -782 = 0 (3w+46)(x-17) =0 x = 17 or x = -46/3 use x = 17 then L = 782/17 = 46
*September 14, 2014*

**math**

over in the triangle between shadows we have a 32 degree angle. At the other end of our 60 meters we have a 180=54 = 126 degree angle. Therfore up at the top of that triangle we have a 180 - 32 - 126 = 22 degree angle law of sines for long hypotenuse ray call it x sin 126/x = ...
*September 14, 2014*

**alg 2**

If x > -8 y < x+8 - 4 or y < x+4 If x <-8 y < -(x+8) - 4 or y <-12 -x
*September 14, 2014*

**Physics**

I answered this a few minutes ago (29.5+15.5)/(5*10^-3)
*September 14, 2014*

**history pt 2**

Romans wanted first of all control of Sicily. Carthaginians wanted the Romans to stop trying to take over their trade routes and territory.
*September 14, 2014*

**Physics**

3/x = 2/(x-5) 2 x = 3 (x-5) 2 x = 3x-15 x = 15
*September 14, 2014*

**Pre-Calculus**

Hey, I did this down below.
*September 14, 2014*

**Pre-Calculus**

5/4 +/- 2 i sqrt(11)
*September 14, 2014*

**Pre-Calculus**

*************_2x^2___________-1x+1 (3x^2 + 13) / 6x^4-3x^3+29x^2+0x+0 **************6x^4_____+26x^2_____ *******************-3x^3+3x^2 +0x+0 *******************-3x^3______-13x ************************ +3x^2+13x+0 ************************ +2x^2____+13...
*September 14, 2014*

**history**

Yes
*September 14, 2014*

**Physics**

change in velocity/change in time = (15.5 +29.5)/5*10^-3 if the second part asks for the average force, multiply by the mass
*September 14, 2014*

**Physics**

how far does it fall in .19 s ? delta h = (1/2) g t^2 = 4.9*.19^2 = .177 meter = 17.1 cm u = 14 d = u t = 14 *.19 = 2.66 m to board
*September 14, 2014*

**Pre-Calculus**

18 x^2 - 6 x +1 = 0 x = [6 +/- sqrt ( 36 - 72) ] /36 = [(1/6) +/- sqrt(-1) ] = 1/6 +/- 1 i
*September 14, 2014*

**Physics**

power = i V 400 = i (120) i = 3.33 rms i peak = i rms * sqrt 2 = 4.71 amps peak
*September 14, 2014*

**Physics**

12 V * 5.9 amps * time in seconds = 4.8*10^3
*September 14, 2014*

**Science**

v = Vi + a t 0 = 100 - 5 t t = 20 seconds
*September 14, 2014*

**Math**

of course if you can not split a pack, it is 63*5 = 315 apples
*September 14, 2014*

**Math**

sells for 2.40/5 = .48 per apple .48 x = 150 x = 313 apples or 63 packs
*September 14, 2014*

**physics**

goes 168 *2 meters in 1 second so 336 m/s that day there.
*September 14, 2014*

**math**

hits x axis at 3 so goes through (3,0) y = 2 x + b 0 = 2 (3) + b b - -6 y = 2 x - 6
*September 14, 2014*

**Physics - Grade 10**

No motion, no work.
*September 14, 2014*

**Math**

hyperbola centered at x =12/2 = 6 hits x axis at (5.5 , 0) and (6.5 , 0) (x-6)^2/a^2 - y^2/b^2 = 1 2 a = 1 a = 1/2 a^2 = 1/4 4 (x-6)^2 - y^2/b^2 = 1 center to either focus = 4 =sqrt(a^2+b^2) so 16 = 1/4 + b^2 b^2 = 16 - 1/4 = 63/4 4(x-6)^2 - 4y^2/63 = 1 (x-6)^2 - y^2/63 = 1/4
*September 14, 2014*

**Whoops**

Sorry about that.
*September 13, 2014*

**Math**

4*4 = 16 compounds 8.5/4 = 2.125% = .02125 1.02125^16 = 1.39995 * 25,000 = 34,998.80 final value - 25,000 = 998.80 interest
*September 13, 2014*

**y is positive down?**

If so then melon trajectory u = 12.1 forever x = 12.1 t so t = x/12.1 v = g t = 9.81 t y = 4.9 t^2 so y = 4.9 x^2/146 = .0335 x^2 y^2 = .00112 x^4 when they hit 14.9 x = .00112 x^4 x^3 = 13303 x = 23.7 y = .0335 x^2 = 18.8
*September 13, 2014*

**Algebra1**

You are welcome.
*September 13, 2014*

**Algebra1**

1x-3x = -2x -4y-3y = -7y 2z+2z = 4z so -2x-7y+4z
*September 13, 2014*

**geometry**

ok, you are welcome.
*September 13, 2014*

**geometry**

4.4 the shape and size are not changed by turning it, so congruent. 5.5 - no idea without seeing it.
*September 13, 2014*

**math**

You are welcome.
*September 13, 2014*

**math**

turn slide translation (same question as 2.2 above)
*September 13, 2014*

**physics**

3.9 E5 km
*September 13, 2014*

**physics**

The point is that 20 min = 1/3 hour
*September 13, 2014*

**physics**

3 km/20 min = 3 km / (1/3)hr = 9 km/hr
*September 13, 2014*

**Math**

93542
*September 13, 2014*

**physics**

v = Vi - g t 0 = 20 - 9.81 t t = about 2 seconds
*September 13, 2014*

**physics**

divide by .707 which is 1/sqrt 2
*September 13, 2014*

**physics**

R the same i2 = 2 i1 so i2^2 R = 4 i1^2R 4 * 22 = 88 Watts
*September 13, 2014*

**physics**

10 Joules is correct to 2 significant figures. Try 10. or 10.0
*September 13, 2014*

**physics**

Hey, I took the course and already know how to do these, now you try and ask us if you get stuck showing where you got stuck.
*September 13, 2014*

**physics**

645 * 590 = 380,550 W or 381 kW Ke = (1/2)m v^2 = (1/2)(4.5*10^4)(900) = 2025*10^4 = 2.025*10^7 Joules energy needed = (2.025/.91)10^7 = 2.225 * 10^7 Joules 3.8055*10^5 t = 2.225*10^7 t = .585*10^2 = 58.5 seconds, about a minute a = delta v/delta t = 30/58.5 = .513 m/s^2 ...
*September 13, 2014*

**physics**

F = G M1 M2 / d^2 d = 2.2+1 = 3.2 mars radius=10.9*10^6 meters = 6.67*10^-11 (3300)(6.42*10^23)10^-12/(10.9)^2 = 1194 * 10^0 = 1194 Newtons
*September 13, 2014*

**Chemistry**

mol of H2 is 2 grams 8.08/2 = 4.04 mols so 4.04 mols of H2O produced H2O = 2+16 = 18 grams per mol 18 * 4.04 = 72.7 grams
*September 13, 2014*

**physics**

Vi up = .85 sin 34.3 = .479 m/s h = 0 + Vi t - 4.9 t^2 h = .479(.078) - 4.9(.078)^2 in meters, multiply by 1000 to get mm
*September 13, 2014*

**Math**

24539
*September 13, 2014*

**AP Calc B/C**

by the way I think you want arch from 0 to pi which Wolfram gives as 3.8 something
*September 13, 2014*

**AP Calc B/C**

yuuk! http://www.wolframalpha.com/input/?i=int+%281+%2B+cos^2x%29^.5+dx
*September 13, 2014*

**Math**

6 is bigger than 5
*September 13, 2014*

**Math**

100,000 for reference then *50,000 *53,000 *53,040 so first digit can be any from 1 to 9 one of those two zeros must remain a zero, the other can be any from zero to nine.
*September 13, 2014*

**Physics**

Hey, look, this is a phony trick question. There is only one force in this problem, gravity, m g Therefore there is only one acceleration in this problem, g , which is about -9.81 m/s^2 on earth. There is NO HORIZONTAL ACCELERATION There is no change in vertical acceleration ...
*September 13, 2014*

**chemistry**

see below
*September 13, 2014*

**Physics**

h = Hi + Vi t - 4.9 t^2 up rock h = 0 + 8.62 t - 4.9 t^2 down rock h = 5.53 - 8.62 t - 4.9 t^2 so when are the two heights the same? 8.62 t - 4.9 t^2 = 5.53 -8.62 t -4.9 t^2 2(8.62 t) = 5.53 solve for t then go back and get h
*September 13, 2014*

**math**

If they are corresponding they are congruent, 44
*September 13, 2014*

**Curriculum**

.... but wait until you meet my six year old grandson.
*September 13, 2014*

**Physics**

1220 Joules/second * 1.3*60 seconds = 95,160 Joules 1.220 kW * 1.3 min * 1 hr/60 min = .0264333333333..... kW h * 12.1 cents = .32 cents
*September 13, 2014*

**math**

change in x = -2-4 = -6 change in y = 3 + 2 = 5 d^2 = 36 + 25 d^2 = 61 d = sqrt (61)
*September 13, 2014*

**Physics**

F = m a = rate of change of momentum first work on a average speed during braking = (14+0)/2 = 7 m/s so time to stop = 23.6 m / 7 m/s = 3.37 seconds change of momentum = -2530*14 =-35420 so F = -35420 / 3.37 = -10510 Newtons mu m g = 10510 mu = 10510 / (2530*9.81) = .423 good ...
*September 13, 2014*

**Help please, :)**

Well, at least your little sister knew he fought in that war long before he led the Continental Army against his former allies.
*September 13, 2014*

**math**

Note, it talks about restrictions. Watch out for zeros in denominators.
*September 13, 2014*

**math**

Great!! You are welcome :)
*September 13, 2014*

**math**

(x-4)/(x^2-8x+16) + 3(x+7)/(x^2+12x+35) (x-4)/[(x-4)(x-4)] + 3(x+7)/[(x+7)(x+5)] proceed just like the other one.
*September 13, 2014*

**math**

I am guessing since your typing without parentheses is ambiguous (x+3)/(x^2+11x+24) - (2x+10)/(x^2+11x+30) (x+3)/[(x+8)(x+3)] - 2(x+5)/[(x+5)(x+6)] 1/(x+8) - 2/(x+6) [ (x+6)-2(x+8) ] /[(x+8)(x+6)] [-x -10 ] / [(x+8)(x+6)]
*September 13, 2014*

**History, Urgent**

You are welcome :)
*September 13, 2014*

**LOL we both found the same article I think.**

Sorry about the repeat. The crux of the matter is that although states could be added to the Union, there was no constitutional provision for taking over foreign territory from another country and making it part of the United States.
*September 13, 2014*

**History, Urgent**

The Louisiana Purchase Treaty would not be final until it was ratified by the Senate, funded by the House of Representatives, and signed by the President. While the incorporation of these new lands into the United States was a momentous opportunity, Jefferson had reservations ...
*September 13, 2014*

**Two for Damon**

As for the other question: 1. is fine although there is much more to being a good coxswain. I would pick 2-2 because it is specific about why you want the big strong guys in the middle. 3. fine 4. fine.
*September 13, 2014*

**Two for Damon**

Posted by rfvv on Saturday, September 13, 2014 at 4:20am. 1. Each team in the Boat Race has eight rowers and one more person who does not row, a cox. 2. Each team in the Boat Race is composed of eight rowers and one more person who does not row, a cox. 3. Each team in the Boat...
*September 13, 2014*

**Physics**

yes, again -g the whole time. Horizontal direction is another problem entirely.
*September 13, 2014*

**Physics**

-g the whole time
*September 13, 2014*

**physics**

show work
*September 13, 2014*

**english**

does, will fly or flies do wakes write began starts
*September 13, 2014*

**math (create equation)**

4 w + 6 L = 88 w L = 80 so L = 80/w 4 w + 6 (80/w) = 88 w + 6 (20/w) = 22 w^2 - 22 w + 120 = 0 w = [ 22 +/- sqrt (484 - 480) ]/2 w = [ 22 +/- 2]/2 w = 12 or w = 10 if w = 12 L = 6 2/3 4 w + 6 L = 88 check if w = 10 L = 8 4 w + 6 L = 88 check
*September 13, 2014*

**english**

shattered :) demolished smashed destroyed .....
*September 13, 2014*

**HISTORY**

DesDes, the American Indians were here before Lief Erikson, never mind Columbus :)
*September 13, 2014*

**HISTORY**

A long before others B 1492 (we all know) C 1517 D 1534 E 1536 F 1588 (We all know that - right ?) G 1620 (did not have to look that up either :)
*September 13, 2014*

**HISTORY**

Columbus went nowhere near Newfoundland in any of his voyages. Columbus was funded by Ferdinand and Isabella of Spain. If he had been anything but Catholic he would have been lucky to escape from their court with his life.
*September 13, 2014*

**History**

yes I think B https://history.state.gov/milestones/1784-1800/pickney-treaty
*September 13, 2014*

**Chemistry**

5000 = (specific heat of gold)(T-25)(33.5)
*September 13, 2014*

**History, Urgent**

Spain had already transferred Louisiana to the French. Anyway, here: http://www.monticello.org/site/jefferson/louisiana-purchase
*September 13, 2014*

**HISTORY**

I agree. That is a central thesis of the book: " The Sea and Civilization" by Lincoln Paine, published by Alfred Knopf, 2013
*September 13, 2014*

**Physical Science**

2NaOH + MgCl2 -> Mg(OH)2(s) + 2NaCl It would be a double replacement reaction and I doubt if it occurs in real life. Everything but the resulting solid precipitate Mg(OH)2 is ions in solution.
*September 13, 2014*

**English**

I would pick (6). However if I were writing it I would say: Each shell has eight rowers and a coxswain who does not row but steers the boat while keeping the rowers working together.
*September 13, 2014*

**English**

1. is fine although there is much more to being a good coxswain. I would pick 2-2 because it is specific about why you want the big strong guys in the middle. 3. fine 4. fine.
*September 13, 2014*

**History**

https://www.mtholyoke.edu/courses/rschwart/hist151s03/french_rev_causes_consequences.htm
*September 13, 2014*

**HISTORY**

When sea level was lower, it was relatively simple to cross the Bering Strait from Asia to Alaska. That is the most likely scenario although it is possible that some Polynesians could have landed on the west coast of South America. They settled most of the Pacific Ocean ...
*September 13, 2014*

**Statistics – Lab Week 2**

You need the mean (average) and the standard deviation http://davidmlane.com/hyperstat/z_table.html
*September 12, 2014*

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