Monday

July 28, 2014

July 28, 2014

Total # Posts: 17,552

**Math**

do you mean (sinT - 1/cosT) or do you mean (sinT-1)/cosT

**physics**

F = G M m /d^2 6.67*10^-11*7.8*10^23*2.5*10^4/57.8*10^16 =2.25 * 10^0 = 2.25 N

**Physics**

for a more elaborate analysis see http://www.braeunig.us/space/propuls.htm read starting around equation (1.11)

**Physics**

initial momentum = 4.6*10^4 * 6.3*10^3 = 29 * 10^7 kgm/s no external forces so that is the final momentum final momentum = ship mass m *7.84*10^3 + exhaust momentum exhaust mass = (4.6*10^4 - m) what is the exhaust speed? I assume that 4.86 * 10^3 is relative to the space ship...

**physics**

(1/2) m u^2 = m g (Hup - Hdown) so u = sqrt(2*9.81*.954) u is horizontal speed, does not change How long in the air? Well, how long to fall .256 m ? .256 = 4.9 t^2 solve for t, time in the air distance horizontal = d = u t

**Physics**

work in = potential energy stored = (1/2) k x^2 double x, four times the energy stored so four times the work in.

**Math!**

You do not need help which ones start with 9 for example? you have a 97, 99, 92, 91, 94, 95, 93, 97 so 9| 1 2 3 4 5 7 7 9

**Physics**

initial momentum = 3.7 * 5 = 18.5 kg m/s mass after crash = 3.7 + 2.0 = 5.7 kg so 18.5 = 5.7 u u = 3.25 m/s which is the horizontal speed until it hits the floor. NOW I DO NOT BELIEVE that your table is 6.9 meters high so I will just outline the rest How long to fall h meters?...

**math**

slope = (7/3) y = (7/3) x + b -3 = (7/3)(-3) + b -3 = -7 + b b = 4 so y = (7/3) x + 4 or 3 y = 7 x + 12

**Math**

initial price = p marked up is 1.1 p then marked down is .9(1.1) p = .99 p

**SCIENCE**

Your stomach

**Intermediate Algebra**

p = 2 L + 2 w 192 = 2 L + 2 w L = 2 w so 192 = 2 (2w) + 2 w 192 = 6 w w = 32 etc

**math**

360/10 = 36 degrees for each piece 3 * 36 = 108 degrees total for the three slices

**Math.**

the first one I am sure is a. Scroll down and look at where this was posted a few minutes ago.

**phy**

how long to fall 50 meters? d = 4.9 t^2 t = sqrt(50/4.9) = 3.19 seconds so how far did it go horizontally? d = u t = 10 * 3.19 = 31.9 meters

**Science**

probably, depends how long it is sitting there and how cold it was when it came out of the freezer and what its specific heat and heat of fusion is and what its shape is, a long tube will melt faster than a sphere of the same mass as you know.

**Science**

NOT a !!!!! c = 3 * 10^8 m/s like period NOT b !!!! either can have any old amplitude for c and d , go look at that chart in the link I gave you earlier

**ALGEBRA! URGENT.**

3 | 7 8 9 ---> 37, 38 , 39 4 | 1 3 7 ---> 41 , 43 , 47 5 | 2 4 ---> 52 , 54 and a. is: a. 37, 38, 39, 41, 43, 47, 52, 54 so I do not think c is right. I am not educated enough in this to look at the rest.

**Physics**

3/4 = .75 hour at 70 ---> 52.5 1/6 = .167 hr at 95 ---> 15.8 1/2 = .5 hr at 55 ---> 27.5 20/60 = .333 hr at 0 --> 0 total time = 1.75 hours total distance = 95.8 km so 95.8 km / 1.75 hr = 54.7 km/hour

**typo**

w = -13 is the other choice, no good

**Intermediate Algebra**

w(w+5) = 104 w^2 + 5 w - 104 = 0 w = [ -5 +/- sqrt (25 + 416)] /2 w = [ -5 +/- 21 ]/ 2 w = 8 or w = 13 L = 8+5 = 13 then A = 8*13 = 104 w = 13 is too big so 8 by 13

**Algebra**

24 x^3 - 3 3 (8x^3 - 1) now 8 x^3 = (2x)^3 perfect cube and 1 = (1)^3 perfect cube and a^3 – b^3 = (a – b)(a^2 + ab + b^2) note a^3-b^3 not +

**Typo**

speed downstream = 12 + c

**Algebra**

Tom can row at the rate of 12 kilometers per hour in still water. He rows upstream for two hours and returns in one hour and twelve minutes. Find the rate of the current. D=r*t R=12 km per hour T= two hours --------------------------- speed upstream = 12 - c speed downstream ...

**Algebra**

Dukes chain saw requires a ration of oil to gas 1 to 40. How many ounces of oil should he add to one half gallon of gas? 8 oz = 1 cup 2 cups = 16 oz = 1 pint 2 pints = 32 oz = 1 quart 4 quarts = 128 oz = 1 gallon By the way " a pint is a pound the world around" :) so...

**Algebra**

A Piece of rope that is 63 meters long is cut into three pieces such that the second piece is twice as long as the first and the third piece is three meters longer than the second. Find the length of each piece. 2x+3x+x=63 --------------------------- need to be more orderly fi...

**Algebra**

Erin has three more dimes than nickles and twice as many quarters as dimes. she has a total of $5.05 How many of each type of coin does Erin have 5.05= 2q-d-3d-n -------------------- but they have different values nickels = n, value = .05 n dimes = (n+3), value = .10(n+3) quar...

**social studies**

inte så mycket Rus

**social studies**

I suspect Scandinavia. Sweden settled Delaware first but I wonder why the Dutch in New York are left out. http://www.colonialswedes.org/History/History.html

**Algebra**

You are welcome :)

**Algebra**

1.08 x = 1620

**Algebra**

same deal with the mowers 1/6 + 1/2 = 1/t 2/3 = 1/t t = 1.5

**Algebra**

Joe does 1/6 room/hour Theresa does 1/10 room per hour together they do (1/6+1/10) = 5/30 + 3/30 = 8/30 = 4/15 of a room /hour so 15/4 hours/room (about 4 hours)

**mathematis**

I guess the first term is -4 and the difference is a = 3 Term n = term 1 + (n-1) a Term n = -4 + (n-1) 3 for example Term 3 = -4 + 2(3) = 2 , good, that works so Term n = -4 + (n-1)3 = 74 3(n-1) = 78 n-1 = 26 n = 27

**Algebra 1**

slope = 4 any other line with slope = 4 will do for the opposite side for example y = 4 x + 53178 then we need two lines perpendicular to those slope = -1/original slope = -1/4 so y = -.25 x + b again any two b values y = -.25 x + 3.14159 and y = -.25 x - 3.14159 or whatever

**algebra**

(-1 -(-1) ) /(-3-6) = 0/-9 = 0 so the slope is zero (of course) it is the line y = -1

**Science**

Look at the chart on the right of that link and the legend beneath it.

**Science**

Ever see a low frequency radio antenna :) ? there are radio waves kilometers long. see: http://en.wikipedia.org/wiki/Electromagnetic_spectrum

**finance**

I forgot to mention that the 30 year pays more per year than the 10 year because in the 30 years inflation may make the income worth much less.

**finance**

Of course as you can see, wealthy people often do not spell well.

**finance**

Well, one of the characteristics of the market is that some people will buy each of them depending on what their priorities are. A retiree with wishes for a very safe income stream might choose the 30 year treasury. A young person who is willing to take a risk for higher retur...

**finance**

yearly income versus safety versus inflation. Why do you think Greece is paying 5 times as much as France? Why do you think a 30 year bond pays more per year than a ten year bond from the same treasury ?(usually) Why do you think an inflation indexed bond might pay negative in...

**Science**

You can not copy and paste here. You could post it to a web hosting site like Scribd and then tell us how to find it (you can not post a link either) but that is a pain.

**Science**

We can not see your picture or diagram or whatever. low frequency is long wavelength is low energy. I have no idea which is brighter. Perhaps one is not in the visible spectrum?

**math**

huh? A /(1 + r/n) = P

**math**

10/20 = 1/2 = .5 meters = 500 cm in (ii) do you not want the WIDTH of the real house If so 80 cm = .8 m .8 m * 20 = 16 meters wide

**science(check answers)**

You have BOTH motion AND position

**science(check answers)**

NO!!!! total mechanical D

**science(check answers)**

I agree. in #7 motion is kinetic and position is potential (for example k x^2 or mgh) so together is total mechanical

**Physic assignment**

momentum before = 1.5*8 + 2*3 momentum after = 1.5*x + 2*7.29

**Cultural Diversity**

I am glad Ms Sue answered these. I looked at them and just shook my head.

**Trig**

tan 37 = h/x tan 58 = h/(5-x) x tan 37 = (5-x) tan 58 x (tan 37+tan 58) = 5 tan 58 x = 5 tan 58/ (tan 58 + tan 37) then h = x tan 37

**Math help**

4 x^2 - 8 = 0 x^2 - 2 = 0 (x-sqrt 2)(x+sqrt 2) = 0 x = sqrt 2 or x = - sqrt 2

**Geometry**

interesting two 5 , 12 , 13 right triangles in there 5 + 12 = 17

**math**

x</= 500 room rent = r = 400 + i x = 500 - (8/4)i cash = [ 500 - (8/4)i ] [400 +i] cash = c = (500-2i)(400+i) c = 20,000 - 300 i - 2i^2 dc/di = 0 for max or min = -300 - 4 i d^2c/di^2 = -4 so max i = -300/4 = -75 for max x = 500 -2(-75) = more rooms than we have so we can n...

**Math**

10 - 3 = 7 18 + 2 = 20 so 7 x + 20

**my mistake !**

then -12 + c = 3 c = -15 No, +15 !!!! put in y = 11 at x = 1 to get d 11 = -1 -6 -15 + d d = 33

**calculus**

I assume you mean y or f(x) = -x^3 +bx^2 +cx + d if so y' = -3 x^2 + 2 b x + c and y" = -6 x +2 b at x = -5 , y' = 0 -75 -10 b + c = 0 at x = 1 , y' = 0 -3 + 2 b + c = 0 so 2 b + c = 3 -10 b + c = 75 -----------------subtract 12 b = -72 b = -6 then -12 + c = 3...

**?**

Sorry, I do not know what that means.

**math**

(5282+4689+3029+6390) / 4 =4847.5 = 4848

**physics**

I assume that a Mg is a "megagram, a term I have never heard before. In that case we have 4*10^6 grams which is 4,000 Kilograms 4,000 * 30 = 120,000 kg m/s south

**physics**

F = G M m/R^2 = m v^2/R so v^2 = G M/R G = 6.67 * 110^-11 M = 6 * 10^24 Re = 6.38*10^6 meters Ra = 6.38*10^6 + .418*10^6 Rb = 6.38*10^6 + .731*10^6

**physics 1**

F = G Mm/R^2 = m v^2/R v^2 R = G M = 6.67*10^-11 * 5.98*10^24 v^2 R = 39.9 * 10^13 v T = circumference = 2 pi R so R = v T/(2 pi) R = v [1.77*10^4/(2 pi)] R = 2.82*10^3 v so v^3 (2.82*10^3) = 39.9 * 10^13 v^3 = 14.1 * 10^10 = 141 * 10^9 v = 5.2 * 10^3 v = 5,200 m/s

**log**

2 = e^.09 t ln 2 = .09 t = .6931 t = 7.7 years

**Trig**

2 sin 3x = 2[ 3 sin x-4 sin^3 x] = 6 sin x - 8 sin^3 x 4 sin 2x = 4[ 2 sin x cos x ] = 8 sin x cos x so 6 sin x - 8 sin^3 x + 8 sin x cos x 2 sin x [ 3 - 4 sin^2 x + 4 cos x ]

**Algebra**

for similar objects volume goes up proportional to cube of the length dimension. Of course people are not always mathematically similar in shape but never the less: ------ my answer is b

**Physics**

NONE !!!! work is force IN THE DIRECTION OF MOTION times distance

**Math help**

1. (Y+5)(Y-7)=0 if Y = -5 then you have (-5+5) (something) = 0 or 0 * something = 0 so 0 = 0 so Y = -5 IS A SOLUTION same deal for Y = 7 (something)( 7 - 7 ) = 0 sure enough y = 7 Is a solution so I claim in general if (something ) (a x + b) = 0 then x = -b/a IS a solution for...

**Chemistry**

Compare the physical and chemical properties of acids and bases.

**Algebra 2**

(5,10),(10,7)= y=(5/3)x-(17/3) m = (7-10)/(10-5) = -3/5 so your m = 5/3 y = (5/3) x + b x --> 15/2 y --> 17/2 so through (15/2 , 17/2) 17/2 = (5/3)(15/2) + b so 17/2 = 25/2 + b b = - 8/2 = -4 y = (5/3) x - 4 agree with your second answer this time

**Algebra 2**

(1,4),(6,-6)= y=(1/2)x-(3/4) m = (-6 -4)/(6-1) = -10/5 = -2 so your m = +1/2 check x ---> (1+6)/2 = 7/2 y ---> (4-6)/2 = -1 so (7/2 , 1) 1 = (1/2)(7/2) + b 4/4 = 7/4 + b b = -3/4 y = (1/2) x - 3/4 I like your first answer

**Algebra 2**

Perhaps I am not being clear. There is no reason the original pair of points would be on the perpendicular bisector of the line between them. In fact they better not be there.

**Algebra 2**

(-5,6),(1,8)= y=-3x+1 m = (8-6)/1+5) = 2/6 = 1/3 so yes, your slope is -3 y = -3 x + b now midpoint x --> (-5 + 1)/2 = -2 y --> (6+8)/2 = 7 so yes the middle is at (-2 , 7) 7 = -3(-2) + b 7 = 6 + b b = 1 so yes y = -3 x + 1 THe original points are NOT on the bisector.

**Math**

150 + 50 + 150 + 50 = 400 meters = 0.4 km .4 km/lap * n = 1 km n = 1/.4 = 2.5 laps

**algebra**

one gallon every 4/3 month so 3/4 mo/gal overcharge gallons = (3/4) gal/mo * t in months 5 = .75 t t = 6 2/3 months

**Pre-Calc Help please**

all logs base 5 64 is 4^3 log (4 x^2) = log 64 = log (4^3) so 4 x^2 = 4^3 x = 4

**health**

Now think about each of those. The only one that is hindered by exercise is the first, diabetes

**Math**

divide first row by 8 to get 1 in upper left 1 1/4 -17/2 add 7 times new first row to second to get 0 below the one 1 +1/4 -17/2 0 +3/4 -9/2 subtract 1/3 times row 2 from row 1 to get rid of that 1/4 in row 1 1 0 -7 0 3/4 -9/2 multiply second row by 4/3 to get 1 in 2,2 spot 1 ...

**Math**

-7 -6

**Math**

augmented matrix +8 +2 -68 -7 -1 +55 you have two rows, three columns now go to http://www.gregthatcher.com/Mathematics/GaussJordan.aspx

**Canals**

It makes New York bigger than Philadelphia :)

**Physics -- check answers please (new)**

Oh, and we disagree on 6

**Physics -- check answers please (new)**

1 c right 2 b right

**Physics -- check answers please**

you did not list them so I do not know what c and b are 6. If I add heat it will get hot I think, unless I subtract more heat :)

**Chemistry**

You are welcome :)

**Chemistry**

well, if I had one liter of the final stuff I would have 6 mols of H2SO4 in it so in 250 mL I need 6/4 or 1.5 mols H2SO4 so the real question is: What volume of 18M H2SO4 contains 1.5 mols of H2SO4 well there are 18 in a liter so I need 1.5/18 liter =.08333...... Liter which i...

**Typo**

3x=4y+5z=10 3x + 4y or 3x - 4y ???

**NEED HELP ASAP !!**

29,035 - (-1,349) = 29,035 + 1,349 =

**social studies**

New Orleans is a seaport and serves as the interface between shipping on the Mississippi River system(Including Missouri, Tennessee, Ohio rivers) and the rest of the world. When you cut a seaport off from the sea, it gets very poor as does the country behind it that depends on...

**social studies**

General Robert E. Lee.

**social studies**

It would be quite remarkable if they did.

**social studies**

Our own (Gloucester MA) General Butler mismanaged New Orleans :)

**4th grade math**

6/8 = 12/16 which is less than 15/16

**4th garde math**

3/5 = 36/60 4/12 = 20/50 so 3/5 is bigger

**Math typo**

.77 + .2 + .16 + .1 = more than 100% You have a typo I doubt if Europe has 77%

**math**

the corners

**Algebra**

B does 1/90 yards/min R does 1/75 yards/min B+R together do (1/90 + 1/75)yards per minute 1/90 + 1/75 = .0244 yards/min 1/.0244 = 40.9 minutes/yard

**basic algebra**

You are welcome :)

**basic algebra**

10 oz pot has 1 oz acid and 9 oz water x oz pot has .25 x oz acid and .75 x oz water so acid = 1 + .25 x water = 9 + .75 x total = 10 + x and (1 + .25 x) = .2 ( 10 + x) 1 + .25 x = 2 + .2 x .05 x = 1 x = 20 oz

**math**

use quadratic equation x = [ -4 +/- sqrt(16 - 24) ]/6 the solution is a complex number because b^2-4ac is negative. Given your last question, I do not think you have covered complex numbers. Perhaps you have a sign error.

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