Saturday

September 20, 2014

September 20, 2014

Total # Posts: 18,581

**chemistry**

125 (95-20)(4.184) Joules divide by 1000 to get kilojoules
*September 20, 2014*

**physics**

Calculate the total distance calculate the total time average v = distance/time
*September 20, 2014*

**Math (Proving of Inequalities)**

a^2-b^2 = (a+b)(a-b) (a+b) is + so if (a^2-b^2) is + then (a-b) must be +
*September 20, 2014*

**5th grade Math**

multiply (2/3) 3 = 2 cups (2/3) 1/2 = 1/3 t (2/3) 3/4 = 1/2 cup (2/3) 4 = 8/3 = 2 2/3 cup (2/3) 2 = 4/3 = 1 1/3 T
*September 20, 2014*

**PHYSICS**

G .35 Mb m/Ra^2 = G Mb m / Rb^2 .35 Mb/Mb = Ra^2/Rb^2 Ra/Rb = sqrt(.35)
*September 20, 2014*

**physics**

well in this case the result is exact, but in general there could be a constant of proportionality between the output and the input that we could not get from dimensional analysis for example Force on a plate of area A in a fluid of density rho in kg/meter^3 and speed v in L/T...
*September 20, 2014*

**physics**

R = v A (look at a drawing of what you have here) now the way you are supposed to do it v = L/T A = L^2 R = L^3/T = (L/T)L^2 so R = L A/T but L/T = v so R = v A
*September 20, 2014*

**chemistry**

2 mol of water --> 2*18 g 1 mol O2 --2*16 g (2*18/2*16) * 7.4 mg = 9*7.4/8 = 8.325 mg 7400 grams O2 ---> 8325 grams H2O ---> 8325 mL H2O or 8.325 liters
*September 20, 2014*

**HELP IN SCIENCE ASAP!!**

yes, yes
*September 20, 2014*

**Science**

You mean 10 m/s^2 I assume wow, 1 g for five minutes ? to the moon ? anyway 5 min = 300 s v = Vi + a t v = 0 + 10 (300) = 3000 meters/second
*September 20, 2014*

**Science**

yes, yes
*September 20, 2014*

**Pre-Cal**

y = +/- sqrt(1-x^2) if y is to be real, x must be x^2 </= 1 -1 < x < +1 similarly y ranges from -1 to + 1 so our function 2 x - 5y is maximum when x is 1 and y is -1 2 + 5 = 7
*September 20, 2014*

**math**

G = 1000 + 325 m E = 2500 + 325 m E always pays more than George by 1500
*September 20, 2014*

**Algebra 2**

1 and 2 fine 3. Evaluate (2.0 x 10^-7)/(8.0 x 10^-9). Write the answer in scientific notation. A: 0.25 x 10^2 but usually written 2.5 * 10^1 age is not a function of last name R = 75 - 3.5 d if d = 5 R = 75 - 17.5 = 57.5 dollars left in pocket
*September 20, 2014*

**Physics**

p Newton = m v p relativistic = m v /sqrt(1 = .75^2) so 100(p relativistic - p newton)/p rel here 1/sqrt(1-.75^2) = 1.512 so 100 ( 1.512 - 1)/1.512 = 33.9 %
*September 20, 2014*

**Physics**

E = m c^2 so m = E/c^2 E = 2*10^9 *21 * 7 *24 *3600 = 2.54*10^16 c = 3*10^8 m/s c^2 = 9 * 10^16 so m = 2.54 / 9 = .282 Kg = 282 grams
*September 20, 2014*

**physics**

You need to know two things: 1. how long does it take to fall 0.7 m 2. How fast is your horizontal velocity after falling 2.76 meters? Then distance = horizontal velocity * time to fall 0.7 meters = u t -------------------------- so, how long to fall 0.7 m? 0.7 = (1/2) g t^2 t...
*September 20, 2014*

**History**

French traders used the Red River to ship to New Orleans from the southern part of Oklahoma. I think they probably mean Red River although indeed the French fur traders also used the Arkansas.
*September 19, 2014*

**History**

None of the others happened in or around 1821 so I would say A
*September 19, 2014*

**physics**

original south = 9.75 cos 25 final south = 8.64 sin 35 original east = 9.75 sin 25 final east = -8.64 cos 35 south a component = (final south -original south)/ .179 east a component = (final east component - original east component) / .179 resultant mag of a = sqrt (south a^2...
*September 19, 2014*

**Math**

x axis intercepts at y = 0 (x-3)(x+1) = 0 x = 3 and x = -1 y axis intercepts where x = 0 y = -3
*September 19, 2014*

**physics**

Vi = 60.32 yes u = 85.3 cos 45 = 60.32 also but forever v = Vi + a t = 60.32 -9.81 t so at top when v = 0 t = 6.15 seconds coasting up h at top = Hi + Vi t -4.9 t^2 = 587 + 60.32 (6.15) - 4.9(6.15^2) = 773 meters high at 6.15 seconds when fall starts now it falls 773 = 4.9 t^2...
*September 19, 2014*

**algebra - check my answer?**

yes
*September 19, 2014*

**Math**

4(x-1)^2 + 3 (x-1) - 3 4(x^2-2x+1) + 3 x - 3 - 3 etc
*September 19, 2014*

**Math**

Yes, what Mia said :)
*September 19, 2014*

**Math**

about x axis? for any x is are there equal in magnitude + and - values of y? y ^2 = x+1 y = +/- sqrt (x+1) so yes but x must be >-1 about y axis? Nah, this is a parabola opening to the right with as vertex at (-1 , 0)
*September 19, 2014*

**Math**

Everything on the number line left of x = -2 including x = -2 so Big black dot on -2 arrow pointing left from there. I do not know what the number six has to do with the problem. B is the only one with all the values in our domain.
*September 19, 2014*

**Math**

w +(w+6) = 34 2 w + 6 = 34 2 w = 28 w = 14 ================== 5 a - 20 - 8 a = 55 -3 a = 75 a = 25 ====================== 6 n - 7 = 45 6 n = 52 n = 26/3 as you wrote it If you mean instead (2n-7)/3 = 15 then 2 n - 7 = 45 2 n = 52 n = 26
*September 19, 2014*

**english**

Illustrator
*September 19, 2014*

**Math**

You are welcome.
*September 19, 2014*

**Math**

n - 6 >/= 2 n >/= 8 agree
*September 19, 2014*

**French**

Everyone always says they are fine even if on the verge of death.
*September 19, 2014*

**History**

agree B turned out to be major.
*September 19, 2014*

**Math**

g / - 5 < -18 if you multiply both sides by -5 you must reverse the direction of the arrow. g > + 90 C.
*September 19, 2014*

**History**

Negotiated relatively safe traffic through Indian lands from Missouri west
*September 19, 2014*

**whoops, -1 not + 1 use Steve's answerr**

dumb error
*September 19, 2014*

**Pre-Calculus Questions**

slope = (-3 - 3)/ (1+5) = -6/6 = -1 y = -x + b 3 = -1(-5) + b b = -2 y = -x - 2 =============================== x axis(0, -3) y axis where y = 0 x^2 - 2 x - 3 = 0 (x-3)(x+1) = 0 x = 3 or x = 1 so axis of symmetry and vertex at x = (1+3)/2 = 2 then y vertex = 4-4 - 3 = -3 so ...
*September 19, 2014*

**History**

Spanish gave up claim to Oregon territory
*September 19, 2014*

**physics**

v = 20 - 9.8 t v = 0 at top 9.8 t = 20 h = 20 t - 4.9 t^2 or m g h = (1/2) m v^2 h = (1/2)v^2/g
*September 19, 2014*

**Mathematics**

(1/2) 116 = 58 (1/2) 8 = 4 tan 58 = 4/h
*September 19, 2014*

**math algebra word problems**

Their speed is 1.5 + 1.2 = 2.7 miles a day
*September 19, 2014*

**physics**

period = 1/ frequency wavelength = period * speed so wavelength = speed / frequency Your textbook must have that !!!
*September 18, 2014*

**Algebra**

2 m^2 + 3 = m 2 m^2 - m + 3 = 0 m = [ 1 +/- sqrt (1 - 24) ]/ 4 = [ 1 +/- sqrt(-23) ]/4 complex conjugate pair.
*September 18, 2014*

**science**

....and you answered the question about how many cars and trucks incorrectly thereby confusing some other poor student.
*September 18, 2014*

**science**

Moreover we do not have the slightest idea what microscopes you might have in your school.
*September 18, 2014*

**physics**

lambda = distance = speed * time Time = period = 1/ frequency
*September 18, 2014*

**Physics**

a = change in velocity/change in time = (14 -0) / 10 2.) zero 3.) (1/2) m v^2 = m g h so v = sqrt (2 g h)
*September 18, 2014*

**Math**

If there were 6 trucks there would be 30 cars and 36 total, no good t + 5 t = 30 6 t = 30 t = 5 not 6
*September 18, 2014*

**math**

no x^n = x * x * x * x .......... n times
*September 18, 2014*

**Math**

balance = 4000 (1.05)^n geometric sequence a = 4000, r = 1.05 4000 4200 4410 etc
*September 18, 2014*

**MATH WORD PROBLEM**

180 = (3/2)x x = 360/3 = 120
*September 18, 2014*

**physics**

a = change in velocity / change in time and F = change in momentum / change in time (Newton #2, F = d/dt (m v) = m a if m is constant)
*September 18, 2014*

**physics**

a = (0-12)/.1 F * t = change in m v F * 0.1 = 60 (0-12)
*September 18, 2014*

**Urgent Spanish Check**

Well, for a bunch of Norte Americanos we are not doing too badly.
*September 17, 2014*

**Urgent Spanish Check**

hmmm, una clase is feminine but lo is masculine. La is feminine.
*September 17, 2014*

**social studies check**

I do not think he accomplished what he was hoping to accomplish. What he did accomplish was not his original objectives.
*September 17, 2014*

**social studies check**

Well, he did not find China. He ended up dead someplace west of the Mississippi. He did get a lot done and was the first European explorer in those parts, however the goals of his sponsors to find vast riches of gold, jewels and silver and find a route to the Orient were not ...
*September 17, 2014*

**social studies check**

I agree with D. It is hard to sustain a culture when everyone is dead.
*September 17, 2014*

**Urgent Spanish Check**

You are welcome.
*September 17, 2014*

**Urgent Spanish Check**

EL examen VERDE miS hermanas LOs
*September 17, 2014*

**social studies check**

I think the key word is PERMANENT. The woodland people were still in place when the Europeans arrived.
*September 17, 2014*

**social studies check**

THey did NOT want to form large plantations as in South Carolina !!
*September 17, 2014*

**physics**

Give ALL the units of resistivity. Then the problem solves itself as long as you know Area of circle = pi d^2/4 Resistance = resistivity * length/area
*September 17, 2014*

**English**

The only problem I have with these sentences is that they are extremely awkward. I would have said: I think I will be a good bow rower because I can balance the boat accurately. I think I will be good rowing in the middle of the boat because I am strong and can make the boat ...
*September 17, 2014*

**Physics please help**

slope of displacement versus time or dx/dt at any point is velocity v = integral of a dt if you were given the ACCELERATION ,a, you would need to do area, but you were not.
*September 16, 2014*

**math**

x y z 4 y z y>z 4 + y + z = 6 y + z = 2 since y>z y = 2 and z = 0 4 2 0
*September 16, 2014*

**Pre-Calculus**

a) so use -3 for x (-3)^2 + 9 = 9+9 = 18 b) now use -2 for x (-2)^2 + 9 = 4 + 9 = 13
*September 16, 2014*

**Calculus I**

dL = a Lo dT L = a Lo T + constant when T = 0, L = Lo so L = (a Lo) T + Lo To is y (or in this case L)axis intercept (a Lo) is slope
*September 16, 2014*

**Curriculum**

The average dictator would name the gerbil :)
*September 16, 2014*

**Math**

A number and its absolute value are equal. SO IT IS POSITIVE OR ZERO if you subtract 2 from the number, the new number and its absolute value are not equal. IT GOT NEGATIVE WHEN WE TOOK 2 FROM IT, SO IT IS BETWEEN ZERO AND TWO 1.9999999999999999999999999999 :)
*September 16, 2014*

**Curriculum**

Way to go Daniela !!!! Much better answers today !
*September 16, 2014*

**Geography**

GDP is entirely financial and may say nothing about how well the residents live. For example a country with huge natural resources such as gold mines may have a high GDP but only a few rich people and the vast majority uneducated and underfed. HDI takes into account how well ...
*September 16, 2014*

**Math**

and for the third time 25 minutes
*September 16, 2014*

**Math**

still 25 minutes
*September 16, 2014*

**Math**

3/5 * 5/3 = 1 entire task :) 15 * 5/3 = 25 minutes
*September 16, 2014*

**chemistry**

Ice water remains at 0 deg C until all is melted. In other words , yes you are correct.
*September 16, 2014*

**Urgent Spanish Check**

gato ends with o
*September 16, 2014*

**Physics**

tourist runs d at 5.56 bear runs (d+26.6) at 7.69 same time for both time = (d+26.6)/7.69 = d/5.56 solve for d
*September 16, 2014*

**maths**

76-47 = 29 47-29 = 18 29-18 = 11 18-11 = 7 11-7 = 4 7 -4 = 3 <--------
*September 16, 2014*

**Physics**

pick some times that meet the criterion north for 30 seconds, south for 10 seconds , total time = 40 seconds distance north from start = 25*30 then back 32*10 total distance north (displacement vector, not distance traveled) = 25*30 - 32*10 so Vaverage = (25*30 - 32*10)/40 = (...
*September 16, 2014*

**Physics**

a) 515/229 b) average speed = (0 + final speed)/2 = answer to part (a) in other words answer to b = twice answer to a c) a = change in velocity/change in time = answer to part b /229 seconds
*September 16, 2014*

**Physics**

Vi = 2.53 Hi = 5.82 0 = Hi + Vi t - 4.9 t^2 4.9 t^2 - 2.53 t - 5.82 = 0 solve quadratic for t eg : http://www.mathportal.org/calculators/polynomials-solvers/polynomial-roots-calculator.php
*September 16, 2014*

**Coordinate Algebra**

y = -3 x + b 4 = -3 (5) + b 4 = -15 + b b = 19 y = -3 x + 19
*September 16, 2014*

**Algerbra**

http://davidmlane.com/hyperstat/z_table.html
*September 16, 2014*

**Social Studies**

I agree with you.
*September 16, 2014*

**Social Studies**

These tricky double negative questions are exasperating.
*September 16, 2014*

**Social Studies**

So C is the answer. Farmers were NOT allowed to own slaves.
*September 16, 2014*

**Social Studies**

the trustees prohibited Negro slavery, for they believed that this ban would encourage the settlement of "English and Christian" people.
*September 16, 2014*

**Social Studies**

No, It was charitable, to help the poor !!!!! One of the reasons they prohibited slavery was to avoid large plantations as had infested South Carolina !!!
*September 16, 2014*

**algebra**

ok, sure, you paid 10 for the right to buy tickets (admission to the fair grounds?)
*September 16, 2014*

**differential calculus**

tan A = h/50 sec^2 A * dA/dt = (1/50) dh/dt dA/dt = (4/50)cos^2 A at h = 50, cos A = .707 and cos^2 A = 1/2 dA/dt = 4/100
*September 16, 2014*

**differential calculus**

p v^1.3 = k p d/dt (v^1.3) + v^1.3 dp/dt = 0 1.3 p v^.3 dv/dt + v^1.3 dp/dt = 0 1.3 p dv/dt = - v dp/dt 1.3 dv/dt /v = - dp/dt /p
*September 16, 2014*

**Algebra**

that last number = (d/2)^2 so 64 = d^2/4 d^2 = 4 * 64 d = 2*8 d = 16 like (x+8)(x+8) then the second one d^2/4 = 49/4 so d = 7 like (x+7/2)(x+7/2) = x^2 + 7 x + 49/4
*September 15, 2014*

**geography**

HUH? They are perpendicular to each other. Meridians run north South and equator runs East west. There is only one equator, around the middle between north and south poles. There are lots of meridians stretching from north pole to south pole and just one is selected (through ...
*September 15, 2014*

**Physical Science**

subtract
*September 15, 2014*

**Chemistry**

every .001 mol Ca(OH)2 needs .002 mol of HCl so we have .002 mol in 25*10^-3 liters .002/.025 = .08 mol/liter
*September 15, 2014*

**Chemistry**

N 14 g/mol H 1 g/mol NH3 is therefore 17 g/mol, 2NH3 is 34 N2 is 28 g/mol every 2 mol of NH3 requires 1 MOL OF N2 so every 34 g of NH3 requires 28 g of N2 so finally 325 g NH3 (28 N2/34 NH3) = 268 g N2
*September 15, 2014*

**Chemisty**

Mg --> 24.3 g/mol 2 O --> 32 2 H --> 2 sum = 58.3 g/mol 17.8 g * (1 mol/ 58.3 g) = .305 Mol ======================================== 123 + 273 = 396 deg K 468 + 273 = 741 deg K P1 V1/T1 = n R = P2 V2/T2 V2 = V1 (P1/P2) (T2/T1) V2 = 20.46 (1.35/1.35) (741/396)
*September 15, 2014*

**Math**

length of ramp is hypotenuse = c length along floor is adjacent = a cos (angle) = a/c
*September 15, 2014*

Pages: **1** | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | Next>>