# Posts by Damon

Total # Posts: 30,061

**Math**

You are welcome.

**Math**

60% of them :) .6*70 = 6*7 = 42

**algebra**

should look like 11 x^2 - 28 x -480 = 0 (11x+60)(x-8) = 0

**you try first**

This time you try first and show work. Same method.

**math**

aaarrrrggh too many of these, use: http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html

**author?**

Try to google story "knife" LOL

**math**

straight up and down, (Y2-Y1)/(x2-x1) = (Y2-Y1)/ 0 undefined

**math**

compounds 24 times a year so r = .03/24 = 0.00125 per period 25 years = 25*24 = 600 periods A = 10,000 * 1.00125^600 = 10,000 * 2.116008731 = $21,160.09

**Science**

6 volt battery resistance of 8 ohms I assume the resistors are also in series i = 6/8 = 3/4 = 0.75 amps

**algebra**

x^2 + (x+6)^2 = (x+12)^2 x^2+ x^2+ 12 x + 36 = x^2 +24 x +144 x^2 - 12 x - 108 = 0 108 is 6*18 for example (x-18)(x+6) = 0 try x = 18 then x+6 = 24 and x+12 = 30 ===================== check 18^2 + 24^2 = 30^2 ???????? 324 + 576 = 900 whew !

**Ethics**

Actually from a maximum utility benefit/cost point of view, I should think B would be the winner.

**Geometry**

length scale = 4/17 area scale = 4^2/17^2 = 16/289 vol scale = 4^3/17^3 = 64/4913 x^3/y^3 = 1728/343 volume ratio x^2/y^2 = 576/y^2 area ratio x/y =(1728/343)^(1/3) = 5.0379^(1/3) = 1.7143 length ratio so x^2/y^2 = 1.7143^2 = 2.939 so 2.939 = 576/y^2 y^2 = 196 meters^2

**Geometry help**

You are welcome.

**Geometry help**

for anything with a pointed top and straight sides the volume = area of base * height *(1/3) so here the side^2*h is the same for each 14^2*24 = s^2*96 or 14^2/s^2 = 4 14/s = 2 s = 7

**Geometry help**

12*12*(9/12) = 108 ft^3 there are 3*3*3 = 27 ft^3/yd^3 108/27 = 4 cubic yards 4*54 = $216

**Chemistry**

Did the vapor pressure of this liquid change when you squeezed the gas down? I think not. Therefore the pressure did not change. You have half as many gas molecules above the fluid. Half the gas molecules condensed back into liquid form.

**HELP PLEASE**

Yes, exactly.

**Calculus**

f(3) = 0 f(0) = 9 slope = (0-9)/3 = -3 f' = -2x where is -2x = -3 ? x = 1.5

**Chemistry**

volume = 2.3 ml mass = 1.0107*10^-2 kg =10.107 grams density= m/v =10.107/2.3 = 4.39 g/mL maybe Titanium ?

**Chem**

3 * .25 * 6 * 10^23

**Chem**

You need 3 mol of A for every mol of B but you only have 2 mol A so you only use 2/3 of a mol of B that would yield 4/3 mol of C but we only got 1 mol of C 100 * 1/(4/3) = 75 % yield

**Math**

Take the average speed during each second times one second and add 6+9+8+7.5+10.5+8.5+6.5+9+8+9 = 82

**Chemistry**

grams/mol N=14 H=1 F= 19 so NH3 =17 F2 = 38 HF = 20 so If I have 4 g of NH3, how many g of F2 do I need? 4/[2(17)] = x/[5(38)] x = 20*38/34 = 22.4 g F2 whoops, not enough F2 so use 14 of F2 and y of NH3 y/34 = 14/190 y = 2.5 grams of NH3 then 2.5/34 = HF/[6(20)] HF = 8.82 ...

**pre algebra**

168 miles/3.5 hours = 48 mi/h

**Chemistry**

See below, I got 500

**Chemistry**

P V = n R T n is number of mols say we have 1 mol (n=1) of argon, 40 grams then we have 40 grams of Methane which is 40/16 or 2.5 mols (n=2.5) they both have the same V and T P/n = RT/V = same for each 200/1 = Pmeth/2.5 Pmeth = 2.5*200 = 500 torr

**Chem 112**

Zn = 65.4 grams/mol Cl = 35.5 grams/mol H = 1 gram/mol so 2HCl = 2(36.5g/mol) = 73 g ZnCl2 = 136.4 g/mol to get 1 gram ZnCl2 need (1/.684)(65.4/136.4)= .701 grams Zn

**Math**

original height = H h(t) = height dh/dt = -2cm/20min = -0.1 cm/min so h = H - 0.1 t h in cm, t in minutes

**phyisics**

You mean it stopped after 8 meters? If so average speed = (3+0)/2 = 1.5 m/s so t = 8/1.5 = 80/15 = 5.33 seconds sliding to a stop then acceleration a = (0-3)/5.33 = -.5625 m/s^2 so now the physics F = m a -m g (mu) = m (-.5625) mu = .5625/9.81 = .0573

**Calculus**

df/dx = -3 df = -3 dx |.05| = -3 |dx| |dx| = .01667 check if x = 1.01667 f(x) = -3(1.01667) + 2 = -3.05+ 2 = -1.05 distance from -1 is .05 sure enough

**chemistry**

answered this below

**chemistry**

2Mg + O2 ---> 2 MgO Mg = 24.3 g/mol O = 16 g/mol so 48.6 grams Mg + 32 grams O2 --> 80.6 grams MgO 5/80.6 = .062 mol MgO produced x/32 = .062 x = 1.985 grams O2 and we needed y/48.6 = .062 y = 3.00 grams of Mg sure enough

**chemistry**

if the masses are equal, the diamond has more volume because it is less dense.

**Math**

well, let's try the 20 on the bottom and the 15 sloping up toward the right. Try the diagonal connecting the two right ends. draw altitude h that divides the base into x and (20-x) x^2+ h^2 = 225 so h^2 = 225-x^2 (20-x)^2 + h^2 = 625 ----------------------- 400 -40 x + x^2...

**science**

original momentum = .04*500 = 20 kg m/s that will be the final momentum so 6 v + .04*200 = .04*500 6 v = .04*300 v = .04*50 v = 2 m/s

**Science**

Probably very hungry. They might not recognize the orchids as food. Many might die. I do not know anything about the relative nutritional value of cactus and orchid flowers. That would determine if a low surviving population would continue feeding on the few cactus plants or ...

**Finite math**

5 c + 7 s + 9 a = 6100 c + s + a = 900 a = .5 (c+s) or 2a - c - s = 0 ============================ add two and three 3 a = 900 so a = 300 c+s = 600 so s = 600 - c 3 c + 7 s + 2700 = 6100 3 c + 7(600-c) = 3400 3 c + 4200 - 7 c = 3400 4 c = 800 c = 200

**Physics 20**

No, the asteroid does NOT have a mass of 2.71 kg. That would be about the mass of a gallon or so of milk. I said 2.71*10^20 kg

**Physics 20**

READ A is 7620 m/s B is 2.71*10^20 kg

**Physics 20**

A is 7620 m/s B is 2.71*10^20 kg and for heaven's sake use SCI units, do not use km and hours or something. Use meters, seconds, Newtons, kilograms. 1 hour = 3600 seconds 1 km = 1000 meters

**Physics 20**

B) v(9.06*10^3) = 2 pi (311) v = .216 m/s I do not think so, suspect you mean 311km not 311 m that would give v = 216 m/s then 7620^2 = G Ma/r 7620^2 = 6.67*10^-11 Ma/311 Ma = 2.71*10^20 kg

**Physics 20**

v^2 = G Me/r v^2 = (6.67*10^-11)(5.97*10^24) /6.85*10^6 v^2 = 5.81 * 10^7 = 58.1*10^6 so v = 7.62*10^3 so v = 7620 meters/second

**Physics 20**

A)when in orbit about earth mv^2/r = m (G Mearth)/r^2 solve for v B) same equation but get v immediately v T = 2 pi r then m v^2/r = m Ma(G/r^2) m , mass of sat cancels we know v solve for Ma

**Physics 20**

I did B

**Physics 20**

Weight is NOT in kg but in Newtons !!!!!! F = m * 9.81 = 154*9.81 = 1510 Newtons

**Physics 20**

A) F = G m Me /r^2 at surface G Me/r^2 = 9.81 B) answer to A*r^2/(r+222,000)^2 but if you try to measure it with a scale, zero because F is balanced exactly by mv^2/R if in orbit which is the answer to part C. Really weight in orbit means nothing.

**Physic**

x = 1.6 (pi)cos(pi*1.3 +pi/3) = 5.03 cos (1.63 pi) = 5.03 * .397

**Algebra**

(A/2) -5 = 35 A/2 = 40 A = 80

**Health**

yes. Despite the act that it ends in s, it is one disease.

**Physics 20 Energy**

m g (change in height) 85 * 9.81 * 2.4 *1000 Joules

**Physics 20**

5(2.5)^2 =5*6.25

**huh??**

It is a four dimensional pool?

**Chemistry**

H2O = 18 g/mol so I have 5.5/18 mols water you get two mols H2O for every mol of O2 so I used 5.5/36 mols O2 O2 = 32 g/mol so 5.5*32/36 = 4.89 grams O2

**Chemistry**

Fe2O3 + Al ---> Al2O3 + Fe same number of mols of Fe as of Al Al = 30 g/mol so 225/30 mols of Al so 225/30 mols of Fe so (225/30) mol mass of Fe (225/30)56 = 420 grams of iron

**Nope**

Look at it on a number line. for positive x-3 x must be to the right of 3 but then sqrt x must be greater than sqrt (x-3) which is not possible. If it were -3 on the right, that would be different (x-3)^.5 - x^.5 = 3 square both sides [(x-3)^.5-x^.5][(x-3)^.5-x^.5] = 9 (x-3)-2...

**Physics 20 Gravity**

11.2 m/s^2 as compared to 9.81 on earth

**Physics 20 Gravity**

g = F/m = G M/r^2 where G = 6.67*10^-11 M = 7.66*10^24 r = 6.74*10^6

**English**

maybe something like: Increased government subsidies would make US manufacturers more competitive with heavily subsidized foreign industries.

**Algebra**

height/shadow = 3.4/1.73 = h/48.25 so h = (3.4/1.73)48.25 which is 3.4 * 48.25/1.73 or 94.8 Draw a picture !!!!

**maths help plz sir damon steve or reiny**

This might help: http://tutorial.math.lamar.edu/Classes/DE/HOVariationOfParam.aspx

**whoops**

825/10,000 or 33/400

**Algebra**

8.25/100 = 825/1000 divide top and bottom by 25 to get = 33/40

**Algebra**

.06*$70 = $4.20 it is supposed to be in dollars accurate to the penny

**Algebra**

120-84 = 36 (36/120)100 = 30%

**Math**

[ (7/3) +2 ] /[-3 -(3/2)] (13/3) / (-9/2) = -26/27 I get B

**chemistry**

I suppose w is weight? I suspect you mean mass in grams water is about 1 gram/cm^3 or 1 kilogram/liter so our NaCl here is .075*1 = .075 kg per liter or 75 grams/liter so the real question is How many mols is 75 grams of NaCl NaCl = 58.5 grams/mol (23+35.5) so 75 g (1mol/58.5g...

**algebra**

7/3 = 2 1/3 or 2.33333.......

**algebra**

0.164*188 = 30.8

**Physics**

h = 20 + .4 t - 4.9 t^2 solve for t when h = 0 just like the problem you posted below this one. also the speed when it hits the ground is the same method.

**Physics**

h = 1.5 + 2.5 t -4.9 t^2 when is h = 0? solve quadratic for t 4.9 t^2 -2.5 t - 1.5 = 0 you could use http://www.math.com/students/calculators/source/quadratic.htm Note, quadratics have two solutions of course. In this problem if you get a neagative time, that is how long ago ...

**Physics**

d = 13.9 * .6 + (13.9/2)t because average speed during deacceleration = half the original speed time to stop during acceleration is t: v = Vi + a t in general so 0 = 13.9 - 3 t t = 13.9/3 so in the end d=13.9*.6 + (13.9/2)(13.9/3) part b will you go 35+9.5 meters in time? what...

**Physics**

a)assume you mean Vx=1.4t^2+1.1t v = 1.4(16) + 1.1(4) b) change in velocity = answer to part a since velocity at t = 0 was 0 so divide a the answer to part a by 4 seconds

**Oh, use Reiny reply**

I did not see the reversal of direction

**Physics (typo?)**

30 min = .5 h 10 min = 1/6 h 20 min = 1/3 h ================= d = 140*.5 + 90/6 + 90/3 (it went 90 for a total of 1/2hour???? typo I bet) average speed = d /total time the way you wrote it the total time is one hour, but I doubt it.

**science doppler to and fro**

what frequency does the blood hear? for observer toward source: f' = f (v+Vobserver)/v f' =6.113*10^6(1570+.3979)/1570 calculate f' the blood particle serves as a transponder sending back a signal at that f' now the source is moving toward the observer f"...

**Physics**

for speed divide the distance by the time for velocity divide the DISPLACEMENT by the time displacement is a vector with x y and perhaps z components. All the way around a track is a Distance of 2 pi r BUT a displacement of ZERO

**science chemistry**

Particles maintain their distance and orientation to other particles in the solid state and only vibrate a little in place so the shape and volume of a lead block does not change (much:). In the liquid state, the particles maintain their distance but not orientation so the ...

**Physics 11 question pls urgent HELP!!!!!**

No The CHANGE in speed is acceleration times time 12.5 * 3.25 That is all you need The initial speed is not relevant. momentum change = mass*change in velocity = 1205*12.5*3.25 kg m/s

**math**

the whole thing is 14 m by 8 m so the walkway area is 14*8 - 12*6

**physics**

here.... +small ...... -big x ......... 0.......... 4.35 just using distances without regard to sign to get equal field magnitudes 1.90/x^2 = 3.61/(x+4.35)^2 solve for x, note it has to be - (left of origin) 3.61 x^2 = 1.9(x^2 +8.7 x+18.9) 3.61x^2 = 1.9x^2 + 16.5x + 35.9 1.71x...

**Science**

The birds reproduce in six months? The birds did not use the O2 in the water directly. Even cormorants breathe air above the water :) However the fish did. I think there might possibly be more fish in 6 months but doubt if the birds would react that quickly.

**oic**

oh, did not notice the "undefined" line is x = 2 vertical line

**Algebra**

slope = (9-2)/(x-2) =7/(x-2)

**Algebra**

LOL - three ways to get at that same parabola

**Algebra**

that is a parabola, where is the vertex? 16 t^2 - 96 t = -h +256 t^2 - 6 t = (1/16)(-h + 256) t^2 - 6 t + (6/2)^2 = (1/16)(-h + 256) + 9 (t-3)^2 = (1/16)(-h + 256) +(1/16)(144) (t-3)^2 = -(1/16)(h-400) vertex at 3 seconds and h =400 ft

**math please help**

so 12.5/100 = 125/1000 = (5*25)/(40*25) =5/40 =1/8

**Further mathematics**

say 15 N along x axis and 10 N 60 deg above -x axis x force = 15 - 10 cos 60 = 10 y force = 10 sin 60 = 8.66 magnitude = sqrt(100+8.66^2) tan angle above +x axis = .866

**Maths lit**

32*0.794 Kg

**Math**

r = 0.045 Ai = 500 dA/dt = Ar dA/A = r dt ln A = r t A = Ai e^rt 2500 = 500 e^.045 t 5 = e^.045 t ln 5 = .045 t so t = ln 5/.045 =1.61/.045 = 35.8 years

**US History**

I am no expert but in this period of westward expansion of cattle range after the Civil War I think both c and d are appropriate answers.

**MATH**

11 - G

**math**

(5/20)100 = 25%

**sorry, yes**

8C4 = 8!/[4!(4!)] = 8*7*6*5/(4*3*2) = 70 so 15*70 = 1050

**MATH HELP**

2 out of 6 administrators 4 out of 6 others combinations of 6 taken 2 at a time = 6!/[ 2!(4!)] =6*5/2 = 15 combinations of administrators combinations of 6 taken 4 at a time = 6!/[ 4!(2!)] = 6*5/2 = 15 combinations of faculty and students so 15*15 = 225

**Partial Sums and finding a certain term**

S3-S2 = term 3 S3 = 13/17 S2 = 8/12 maybe 13/17 - 8/12 ??? about .098

**Algebra**

-11 x^5 +4x +8x^3 -13x -2 +7x^3 -11x^5 +15 x^3 -9x -2

**Triangles math**

fraction = percent /100 2*0.5 and 3*0.5 2*3 and 3*3 2*5 and 3*5

**math**

2/5 of 5/12 = 1/6

**math**

2/3 left after pie 3/8 of that left 2/3 * 3/8 = 1/4 really the same as your problem above

**social studies**

and you are right.