Monday

September 22, 2014

September 22, 2014

Total # Posts: 18,627

**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*

**English 1**

Make a guess !
*September 12, 2014*

**Physics**

a = change in velocity / change in time = 37 m/s / .177 s
*September 12, 2014*

**math TYPO I think**

suspect you mean a cone v = (1/3) pi r^2 h (need that r^2) 3 v = pi r^2 h h = 3 v / (pi r^2)
*September 12, 2014*

**math**

520 t + 620 (t-1) = 1800
*September 12, 2014*

**math**

t and (126 -t) 4 t = 2 (126-t) solve for t then d = 4 t or d = 2(126 - t)
*September 12, 2014*

**math**

x and 14000-x .04 x + .025 (14,000-x) = 458 solve for x and then do 14,000-x
*September 12, 2014*

**Algebra**

x (a + b +2) distributive of multipication (x+3)(a+b) distributive again and I also used commutative to make 3+x --> (x+3)
*September 12, 2014*

**math More infor needed**

I assume the second object is stationary ? We need to know how soft it is. In other words we need to know the time duration of the crash. F * time spent scrunching = momentum of 40 ton object
*September 12, 2014*

**Mathematica**

(1/3) (x+1) = 3/5 x+1 = 9/5 x = 4/5 = .8 .8*100 = 80 % check add .8*1/3 to 1/3 .8/3 + 1/3 = 1.8/3 18/30 = 3/5 sure enough
*September 12, 2014*

**math**

You are welcome :)
*September 12, 2014*

**math**

my calculator says yes that works :)
*September 12, 2014*

**math**

.4 + 5/100 + 5/1000 + 5/10,000....... .4 + 5/100 +(5/100)(1/10) .. .4 + infinite geometric series with a = 5/100 and r = 1/10 .4 + sum of series .4 + a/(1-r) .4 + 5/100 / (9/10) 4/10 + (5/9)/ 10 (4 5/9 )/10 41/90
*September 12, 2014*

**Pre-Calculus/Trigonmetry**

You are welcome :)
*September 12, 2014*

**Pre-Calculus/Trigonmetry**

If it is parallel to the x axis then it is y= something in this case y = 4
*September 12, 2014*

**Algebra**

28 * 2 = 56 84 - 56 = 28 28/2 = 14 so we have 28*14 if rectangle 28* 14 = 392 yd^2
*September 12, 2014*

**chemistry**

copper sinks so volume is increased by copper volume. volume of copper = 6.5 g * 1 mL/8.96 g = .725 mL so .725 + 13.4 = 14.1 mL
*September 12, 2014*

**Pre-Calculus**

m' = -1/m m' = -1 /(1/2) = -2 correct 2. yes true 3. m = (1-5)/(-3-1) = -4/-4 = 1 so false
*September 12, 2014*

**Physics**

x is generally taken positive to the right (east) F1x= -416 sin 10 = -72.2 F2x = 356 sin 30 = 178 so Fx = 106 F1y = 416 cos 10 = 410 F2y = 356 cos 30 = 308 We must be operating on different number systems :( Fy = 718 tan angle up from x axis (east) = 718/106 = so angle up from...
*September 12, 2014*

**physics TYPO**

northeast is not 300 degrees. It is 45. what are you talking about ?
*September 12, 2014*

**math**

.9 x = 36 x = 36/.9 = 40
*September 12, 2014*

**physics**

average velocity = -617/105 = -5.88 m/s and average speed = 5.88 m/s ================================ in anticipation of a part B: x = Xi + Vi t + (1/2) a t^2 -617 = 0 + 0 t + (1/2)a (105)^2 a = -1234/105^2 a = - .112 m/s^2
*September 12, 2014*

**Physics help please!**

I assume you are talking about a nuclear reaction. In that case some mass is released as energy by the relationship E = m c^2
*September 12, 2014*

**Algebra**

yes, or complete the square -(1/2) x^2 + 20 x = A - 800 x^2 - 40 x = -2 A + 1600 x^2-40x+20^2 = - 2A + 2000 = -2(A-1000) (x - 20)^2 = -2 (A-1000) vertex at x = 20, A = 1000
*September 12, 2014*

**Math, Physics**

distance = rate * time d = 1.9 *initial speed * cos 46 now vertical problem Vi = initial speed * sin 46 v = Vi - 9.8 t at top 0 = Vi - 9.8* (1.9/2) time up is half total time so Vi = [ 4.9 * 1.9 ] so initial speed = [ 4.9 * 1.9 ]/sin 46 then go back to d = 1.9 *initial speed...
*September 11, 2014*

**Physics repeated question**

been there, done that.
*September 11, 2014*

**Physics**

v = Vi - 9.81 t 0 = 1.23 - 9.81 t solve for t then double it if you want to come back down.
*September 11, 2014*

**Math**

top line (1 + 2) + (3 + 4) = 10 = (1+3) + (2 + 4) = 10 associate property of addition d. as for the rest c. add y values 2+4 = 6 now 1 + 6 + 3+6 = 16 NO e. sum of x values + sum of complex conjugates of y values?
*September 11, 2014*

**algebra 1**

rod d = v * 5 hours Marsha d = (v+42) * 2 hours so 5 v = 2 v + 84
*September 11, 2014*

**Maths**

sin theta = 2.1/3.8 = opposite/hypotenuse ================================ same thing sin theta = 0.75/5.4
*September 11, 2014*

**math**

4 x^2 - 4 x + 5 = 0 x = [ 4 +/- sqrt (16 -80) ]/8 = 1/2 +/- (1/8)sqrt (-64) = 1/2 +/- i
*September 11, 2014*

**maths b**

http://davidmlane.com/hyperstat/z_table.html
*September 11, 2014*

**maths a**

http://davidmlane.com/hyperstat/z_table.html careful about parentheses z= (x-u)/SD = (34.5 -46.5) /8.7 = - 1.38
*September 11, 2014*

**maths a**

English z = (68-52)/10 = 1.6 SDs above average Math z = (68 - 55)/8 = 1.625 SDs above average, better
*September 11, 2014*

**2**

a = 6500/60 then divide by 9.8
*September 11, 2014*

**2**

forget speed of light in this context, so much faster than sound that basically it is infinite. All that matters is the creeping speed of sound. 6.5 s * speed of sound in air = distance then divide that distance by 3*10^8
*September 11, 2014*

**1**

6.5 * 343 (Ignore speed of light)
*September 11, 2014*

**phusics**

x = Xi + Vi t + .5 a t^2 10 = 20 t - 5 t^2 solve for t or just use average speed up = 5 m/s so time = distance/speed = 10/5 = 5
*September 11, 2014*

**Science**

work done = change in Ke (1/2) (.5)(v^2) = 810 * 4 * 10^-3
*September 10, 2014*

**Physics**

980 * .25 Newtons
*September 10, 2014*

**Physics**

a = 3 m/s^2 Vi = 0 d = 24 m d = (1/2) a t^2 24 = (1/2)(3)t^2 t^2 = 48/3 = 16 t = 4 seconds v = Vi + a t v = 0 + 3 (4) v = 12 m/s
*September 10, 2014*

**math**

(1/3)Jill + 10 = 55 Jill / 3 = 45 Jill = 3 * 45
*September 10, 2014*

**Algebra 2**

x = [ -10 +/- sqrt (100 + 80) ]/2 x = -5 +/- .5 sqrt(180) x = -5 +/- .5 sqrt ( 9 * 4 * 5) x = -5 +/- 3 sqrt 5
*September 9, 2014*

**science**

200 meters in 5 seconds average speed = 200/5 = 40 m/s so speed is 80 m/s at 200 m it slows down after that so 80 is your answer goes at 80 for 300 m time = 300/80 = 30/8 = 15/4 seconds between 200 and 500 now from 500 m and 80 m/s, brakes down to zero at -2 m/s^2 0 = 80 - 2 t...
*September 9, 2014*

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