Saturday

September 24, 2016
Total # Posts: 27,150

**Physics**

v = Vi - g t 0 = 24 - 9.81 t t = 24/9.81 h = 24 t -4.9 t^2

*September 3, 2016*

**Algebra**

I bet you mean 4√(490k^2 ) which is 4k √(490) which is 4k √(7*7*10) which is 28 k √10

*September 3, 2016*

**Calculus**

x = 2+ln(y-5) x-2 = ln(y-5) e^(x-2) = y-5 y = e^(x-2) + 5

*September 3, 2016*

**Calculus**

e^0 = 1 2x = 7 x = 3.5

*September 3, 2016*

**math/Calculus**

x = csc y = 1/sin y sin y = 1/x y = sin^-1(1/x)

*September 3, 2016*

**Calculus**

if g' is-1 which is as negative as it could be then g will be +1 at x=1 which is as low as it could be anywhere in the interval. Meanwhile f' could be+1 which would also make f = +1 at x = 1 which is a big as it could be. therefore f is always less than 1 and g always ...

*September 3, 2016*

**algebra**

after a year x = x + .03x = 1.03 x every year multiply by 1.03 2000 (1.03)^6

*September 3, 2016*

**Algebra**

You are welcome and I am from a fishing town north of Boston where we rise early.

*September 3, 2016*

**Algebra**

and in the second one a sign error (x-4y+5)(x-4y-5)

*September 3, 2016*

**Algebra**

Yes, you are right

*September 3, 2016*

**Algebra**

maybe complete the square? (x^2-8xy+16y^2) -16y^2 +16y^2-25 (x-4y)^2 - 5^2 (a-b)^2 = (a+b)(a-b) (x-4y+5)(x-4y+5)

*September 3, 2016*

**Algebra**

I am not sure what you want but 8 = 2^3 125 = 5^3 64 = 2^6 = 4^3 (2x/5)^3 + (4/y)^3 but a^3 + b^3 = (a+b)(a^2-ab+b^2) (2x/5+4/y)(4x^2/25-8x/y+16/y^2)

*September 3, 2016*

**Algrebra**

first line 5 y = 3 x - 9 slope = -3/5 second line assume you mean 2x+ky=11 k y = -2 x + 11 slope = -2/k now for parallel, same slope -3/5 = -2/k k = 10/3 for perpendicular new slope = -1/oldslope 5/3 = -2/k k = -6/5

*September 3, 2016*

**Math**

S + (70+S) + (70 + S + 50) = 730 3 S + 190 = 730 3 S = 540 S = 180 (70 + S + 50) = 120+180 = 300

*September 2, 2016*

**math typo**

1st case (x+1)/(y+1)= 3/4 2nd case. (x-3)/(y-3)= 1/2 not y-4

*September 2, 2016*

**Physics**

755/18 I have a sneaking suspicion that there is more to this question. Surely they then ask for the average velocity for the entire round trip which is zero because you return to the same spot and the total displacement is zero.

*September 2, 2016*

**Physics**

v = g t = 9.8 * 3.5 = 34.3 m/s I agree with you.

*September 2, 2016*

**Physics**

Vi = 3 0 = 9.5 + 3 t - 4.9 t^2 solve for t

*September 2, 2016*

**Algebra 1**

33 - g = 2 g - 9 42 = 3 g g = 14 m = 33-g = 19

*September 2, 2016*

**MISSION**

(pi d^2/4)h = V h = 4 V/(pi d^2)

*September 2, 2016*

**Math concepts**

in the ones place two. 3, 5 note: --- in higher places can be zero, like 010 = 10 so 10 of them in the tens place ten so 20 to date in the hundreds place ten so 200 in the thousands place ten so 2000 10003 is too big so none allowed in ten thousands place so I get 2000

*September 2, 2016*

**Algebra**

maybe you mean h(n) = -3 • 4^(2n+1) ????? h(2n) = -3 * 4 ^(2{2n] +1) = -3 * 4^(4n+1)

*September 2, 2016*

**geometry**

SR = TQ midpoints of equal lengths < SRQ = < TQR base angles of isoceles triangle RQ = QR same line segment so side, angle, side

*September 2, 2016*

**geometry**

ADB is congruent to ADC --- side, side, side the end really

*September 2, 2016*

**S.S**

I guess so, but living in a fishing town I do not call salt marshes an "obstacle".

*September 2, 2016*

**Science**

initial x momentum = .3*5 initial y momentum = 0 final x momentum = .3 Ux + .4(2)cosA final y momentum = .3 Vx + .4(2)sinA tanA = Vx/Ux = sin A / cos A

*September 2, 2016*

**Math**

I do not see your geometry arrangement. However in general change in volume = surface area of liquid * change in surface height dV = Area * dh dV = pi r^2 dh so dV/dt = pi r^2 dh/dt (1/4) = pi r^2 dh/dt so dh/dt= 1/( 4 pi r^2) You will have to find r from your geometry at ...

*September 2, 2016*

**physics**

I guess it goes (you do not tell me) spring x = 0, S down Pivot at x = 0.30, P up Board wt of 30*10 = 300 N at x = 1 down Diver wt of 60*10 = 600 N at x = 2 down P = S + 900 moments about x = 0 .3 P = 300*1 + 600*2 .3 P = 1500 P = 15000/3 = 5,000 N S = P - 900 = 600 N

*September 2, 2016*

**someone please help!! i need to finish this!!**

Too many, ask specific question if stuck. eg cross out first row and column | -2 +6 | | +3 -6 | = 12 - 18 = -6

*September 2, 2016*

**Science help immediately**

Yes, feedback

*September 2, 2016*

**College Physics**

so how many Joules do you need? potential energy = m g h = 3 *10^-3 *9.81* 10^-2 = .5*9*10^-6 V^2 30*9.81 = .5*9 V^2

*September 1, 2016*

**Physics**

the acceleration is about 9.81 m/s^2 down the entire trip velocity is zero at the top. It stops then falls. it went up for 1.9/2 = 0.45 s v = Vi - g t at top v = 0 0 = Vi - 9.81 (.45) so Vi = 9.81*.45 h = Vi (.45) - 4.9 (.45)^2 h is height above your hand

*September 1, 2016*

**Singapore way ? someone expert?**

I suspected from the phrasing of the question that the student is taking a subject based on the Singapore approach. My underlines (like _ ) are intended to be boxes. Did I do this right? I know 18 is right, but the explanation is new for me.

*September 1, 2016*

**Math**

lion _ monkeys _ _ _ total _ _ _ _ what times 4 = 24 6 so Lion 6 monkeys 6 6 6 or 6*3 = 18 (I am trying to learn Singapore math :)

*September 1, 2016*

**Math**

18 4/6 - 17 5/6 17 10/6 - 17 5/6 5/6

*September 1, 2016*

**History! Help!**

When that wild Mongol Tamerlane destroyed the irrigation systems in Mesopotamia (Iraq now) in around 1400 AD it was several thousand years old so surely a few thousand BC

*September 1, 2016*

**math**

By the way there are multiple answers to these for example sin 50 = sin 130 = cos 40 = -cos130

*September 1, 2016*

**math**

Hint: Draw the four Quadrants on a graph Draw line length 1 at 50 degrees up from the x axis Draw line length 1 at 50 degrees up from the -x axis sadme sine for 50 degrees and 180 - 50 degrees so sin 50 = sin 130

*September 1, 2016*

**Social Studies**

I wonder which side of the Interexcolony War Ethan Allen and the Green Mountain Boys took.

*September 1, 2016*

**You decide**

I am simply not going to just give you the answer. What do you think? Meanwhile I will contemplate the state militias at war.

*September 1, 2016*

**English Check**

Whew, that is settled.

*September 1, 2016*

**English Check**

The advice was meant for YOU. ok The advice was meant for ME. ok so which do you think ? Would you really say: "The advice was meant for I" ? They are objects

*September 1, 2016*

**Social studies**

I think the last one, religion.

*September 1, 2016*

**Social studies**

Protestants versus Catholics

*September 1, 2016*

**Social studies**

yes no - property owners. Originally you had to be a Puritan.

*September 1, 2016*

**Social studies**

In North America it was the imported diseases from Europe that wiped out the natives. I suspect the same happened to the south.

*September 1, 2016*

**Social studies**

We are pretty proud of our public school history around here.

*September 1, 2016*

**History**

By the way, during most of WW2, I never really understood that the Japanese were enemy. I thought it was just Germans because I did not know any Germans. Japanese people were friends and neighbors in my life. It was impossible that they were bad guys.

*September 1, 2016*

**History**

They assumed that since they were Japanese in ancestry they might help the enemy Japan. It turned out to be nonsense. { My story: I was in Kindergarten in Honolulu when the Japanese bombed us. Many of my school mates and friends were Japanese Americans. In fact I think the ...

*September 1, 2016*

**History**

I bet you mean "code talkers". That usually refers to Navajo Indians who served the US Army in WW2 as communicators. Foreigners might be able to break most codes but had trouble with Navajo. See for example: http://en.wikipedia.org/wiki/Code_talker

*September 1, 2016*

**Statistics**

http://davidmlane.com/hyperstat/z_table.html

*September 1, 2016*

**chemistry**

Well, I suppose mass was conserved 10.2 + 66.9 = 77.1 ------------------------ You can stop there. ------------------------ Now let's check if they are in the right ratio 2 H2O ---> 2 H2 + O2 2 mols of H2 for every mol of O2 mol of H2 has mass 2 g mol O2 has mass 32 g ...

*September 1, 2016*

**science**

always multiply b something that is the same top and bottom except for the name of the unit for example 100 cm / 1 m is the same top and bottom so is 1 m/ 100 cm so if I have 105 m and I want cm I do 105 m (100 cm/m) = 10500 cm or 2000 mL (1 L / 1000 mL) = 2 L or 3400 g (1 kg/...

*September 1, 2016*

**Math**

slope = m = 4 y = 4 x + b -1 = 4(-5) + b b = 19 y = 4 x + 19

*September 1, 2016*

**Mathematics**

60 * 1/4 = 60/4 = 15 km 36 t = 15 t = 15/36 hour 15/36 * 60 = 25 minutes

*September 1, 2016*

**math**

boy does x jobs/day girl does y jobs/day (2 x + 5 y)4 = 1 job (4 x + 4 y)3 = 1 job 8 x + 20 y = 1 12 x + 12y = 1 2 x + 5 y = 1/4 2 x + 2 y = 1/6 ===============subtract 3 y = 3/12-2/12 = 1/12 y = 1/36 so a girl does (1/36) jobs /day find x and you know jobs/day a boy does If ...

*September 1, 2016*

**nor do I**

how much is a boy paid? boy does x jobs/day

*September 1, 2016*

**american history**

and was Maryland not a Roman Catholic colony at first?

*September 1, 2016*

**american history**

Oh , I missed no answer to 8 Most white colonists were farmers who prospered due to affordable land.

*September 1, 2016*

**american history**

1. I assume that you are talking about migrants from Asia across the North Pacific/ Bering Sea. These were nomadic tribes in general. 2 and 3 agree 4. I was not aware the the Dutch and French were fierce enemies particularly in North America. However they certainly did have ...

*September 1, 2016*

**Math**

(6/10 - 3/10)F = 60 3 F = 600 F = 200

*September 1, 2016*

**isoceles triangle?**

maybe? b + 2(b+7) = 95 3 b + 14 = 95 3 b = 81 b = 27

*September 1, 2016*

**physics**

mass of water = 44-18 mass of stuff = 39-18 density of stuff = 1 gram/cc * mass of stuff/mass ofwater

*September 1, 2016*

**Math**

24/10 - 13/10 = 11/10 = 1 1/10

*September 1, 2016*

**American government**

http://www.archives.gov/federal-register/constitution/

*September 1, 2016*

**math**

.31 + .20 = .51

*September 1, 2016*

**AP Biology**

http://www.chemspider.com/Chemical-Structure.84989.html 324.4 grams/mol so 100.7/275 = x/1000 x is grams in a liter divide x by 324.4 to get mols in a liter

*September 1, 2016*

**AP Biology**

22.4 liters/mol at stp so how many mols? 150/22.4 approximately (it does not say if we are at stp) grams of O2 = mols * 32

*August 31, 2016*

**Algebra 2**

L w = 51 2L + 2 w = 40 so L+w=20 51/w + w = 20 w^2 - 20 w + 51 = 0 w = [ 20 +/- sqrt (400 - 204)]/2 = [ 20 +/- 14]/2 so 3 by 17

*August 31, 2016*

**Forensics**

(1/2)^n = 1/16 n = 4 half lives 4 * 29 = 116 years if you did not see that 2^4 = 16 then you could do .5^n = .0625 n log .5 = log .0625 n = log .0625 / log .5

*August 31, 2016*

**Math**

50 + 100 = 150 m/h combined speed 150 t = 400 t = 40/15 = 8/3 = 2 2/3 hr = 2 hours and 40 minutes

*August 31, 2016*

**Technology**

Perhaps Livy is not using a keyboard and so can not look at those two keys closely.

*August 31, 2016*

**Technology**

I am puzzled. They are the keys your index fingers (not middle fingers) should rest on.

*August 31, 2016*

**Physics**

2.38*10^6 2.38 million = 2,380,000

*August 31, 2016*

**whoops sorry**

yes r = 0.05/52 weekly not daily !

*August 31, 2016*

**math**

.05 / 365 = r 4*52 = 208 = n x (1+r)^n = 3000 x = 3,000/(1+r)^n

*August 31, 2016*

**Algebra**

sqrt (17) real not natural not whole not rational not integer irrational

*August 31, 2016*

**math**

look up sinking fund formula r = .04/12 rate per month n = 10*12 = 120 months 250 = P /[ (1+r)n -1]/r so P = 250 [ (1+r)n -1]/r

*August 31, 2016*

**Math**

50(t-1) + 45 t = 330 95 t - 50 = 330 95 t = 380 t = 380/95 about 3 hours

*August 31, 2016*

**math work**

Maybe a vector 94 i + 93 j for example | 2 3 | |94| | 1 2 | |93| would be matrix times vector V = 94 i + 93 j

*August 31, 2016*

**watch parentheses!**

(2-x)/(2+x) maybe? if x = 2, numerator is zero, expression is zero if x = -2 Explodes, undefined

*August 31, 2016*

**math work**

do you mean u dot (v X w) ???? if so vXw = +i +j +k -6 +1 -5 +2 +8 -9 = (-9 +40)i + (-10-54)j +(-48-2)k -49i -64j -50 k now dot with + 9i - 7j - 3 k ---> -441 + 448 + 150 157 CHECK MY ARITHMETIC

*August 31, 2016*

**math work**

I think you mean orthogonal not octagonal a. vector normal (perpendicular to) first plane 4 i + 5 j +1 k second plane 3 i + 5 j -37 z find the dot or cross product dot is easier A dot B = |A||B| cos angle between if cos is 0, they are othogonal because cos 90 degrees is 0 if ...

*August 31, 2016*

**math**

You are welcome.

*August 31, 2016*

**math**

x = -2 + steps right y = -5 + steps up so x = -2 + 1 = -1 y = -5 + 3 = -2 (-1 , -2)

*August 31, 2016*

**Math**

65 + x = -12 x = -65 - 12 = -77 so 4

*August 31, 2016*

**?**

dilated how much?

*August 31, 2016*

**Math**

n and n+1 1/n + 1/(n+1) = 17/12 12(n+1) + 12 n = 17 n(n+1) 12 n + 12 + 12 n = 17 n^2 + 17 n 17 n^2 - 7 n - 12 = 0 hummm, suspect typo

*August 31, 2016*

**ah, magic ?**

I do not see the figure.

*August 31, 2016*

**Algera check answers**

Which of the following is the most appropriate unit to describe the rate at which data is transferred using the internet? =========================== Time needed is a function of megabits of data. D yes ========================== 2 + (x + y) = (2 + x) + y is an example of ...

*August 31, 2016*

**math**

4 10/15 - 3 6/15 = 1 4/15

*August 31, 2016*

**Physics**

50 * 9.81 * 2.4 = about 1200 J If you say g = 10m/s^2 you get exactly 1200 J

*August 31, 2016*

**Physics**

a = change in velocity/change in time = -20/4 = -5 m/s^2 F = m a = -300*5 = -1,500 Newtons

*August 31, 2016*

**math**

x^-n = 1/x^n 5 * 10^-2 = 5/10^2 = 5/100 = 0.05

*August 30, 2016*

**math**

( distributive property :)

*August 30, 2016*

**math**

if I have 100 dollars and increase that by 5% I then have 100*1 + 100*0.05 which is 100 (1.05)

*August 30, 2016*

**Physics**

s is initial speed Vi = s sin 6 v = Vi - g t at top v = 0 t = s sin 6 / 9.81 u = s cos 6 11 = u t t = 11/(s cos 6) so 11/(s cos 6) = s sin 6/9.81 solve for s, the initial speed get t then h = .39 + Vi t - 4.9 t^2 for part b u = s cos 6 new u = .25 s cos 6 then t to fall from h...

*August 30, 2016*