# Posts by Damon

Total # Posts: 31,631

Maths
I am going to guess that your mean: 1/(1-x) + 2/(1+x) multiply tops and bottoms by [(1-x)(1+x)] [(1+x) + 2(1-x) ] /(1-x^2) **** remember a^2-b^2 =(a-b)(a+b) *** = [3 - x]/(1-x^2)

Physics-Graivty
F = G m M/r^2 F' = G m 2M/(2r)^2 F'/F = 2/4 =1/2 700* 1/2 = 350 N

Physics
100 = V i so i = 100watts/110 volts=about 1 coulomb/second (you use calculator) e = 1.6*10^-19 coulomb so (1/1.6)*10^19 electrons/second so 800 hours = 800*3600 seconds = 8*3.6*10^5 seconds so (8*3.6/1.6)* 10^24 electrons (quite a few)

5 kg*40cm = m kg *30 cm m = 5(4/3) = 20/3 kg

Trig
volumes of similar objects have dimensions proportional to length dimension cubed 800/2700 = 8/27 = 2^3/3^3 = (2/3)^3 so (2/3)15= 10 inches radius

Physics
(1/3)^2 = 1/9 so r = 3 re from earth center=19200 subtract re to get above surface so 19200-6400= 12800 km

statistics
like permutations = 10!/(10-3)!

Geometry
6 in expands to 36 in that would be times 6 10 in expands to 48 in that would be times 4.8 so the 10 inch dimension is limiting and the scale ratio is 4.8 6*4.8 = 28.8 inches so what is used is 28.8 in x 48 in

Chemistry
N = 14 g/mol O = 16 g/mol 2 Mols N2O5 = 56+160 = 216 grams 1 mol O2 = 32 grams so 32 grams O2 for each 216 grams N2O5 so (32/216)44.2

math
If you want the length of the mast and not the height, subtract 24 ft from the height.

mechanics
impulse is change of momentum .75 * 7 kg m/s or Newton seconds final speed/initial speed = 2/5 (1/2) .75 (25) (1/2) .75 (4)

Hey, come on
been there, done that.

physics
initial momentum north = final momentum north so 6,000*5 = 10,000* Vn same for west 4,000*15 = 10,000* Vw speed = s = sqrt(Vn^2+Vw^2) tan angle north of west = Vn/Vw initial Ke=(1/2)[6000*25+4,000*225) final Ke = (1/2)(10,000)s^2

Not possible
unless it has rocket propulsion it will not drop from 8 and rebound to 12

geometry
mast casts a 96 foot shadow? mast height = 24 * (96/64)

PHYSICS
the force is the same in each so add the extensions: mg/k1 + mg/k2

physics help
force = mass * centripetal acc = m v^2/r c = 2 pi r = 2 pi * 1.8 v = (c/6.2) meters/second so F = 20 * (c/6.2)^2/1.8 when F = mu * m g, we slip mu = Ac/g= (c/6.2)^2/(1.8*9.81)

calculus
Well, supposed to be your words, not mine. If a variable y depends on x as a continuous smooth function y = f(x) and we want to find the rate of change of y as x changes then on a graph, that is the slope of a tangent to the function, change in y / change in x at the point (x,...

Physics
dv/dt = 9 - 12 t and v(0)= 0 v = 9 t - 6 t^2 + constant when t = 0, v = 0 so constant = 0 v is radians/sec v = 9 t - 6 t^2 at v = 0 0 = t(9-6t) so v = 0 at t = 0 as we knew and v = 0 at t=9/6 = 3/2 = 1.5 so how far did it go? x is radians x = (9/2) t^2 - (6/3)t^3 + 0 x = (9/2...

It is probably the minimum speed you mean. The centripetal acceleration must be at least 9.81 m/s^2 on earth or the string will go slack and the ball will fall on your head. Now you have given enough information already to find out. By the way, any old mass m will do v^2/r>...

Math
At the same store, Peter bought 2 pairs of pants and 5 shirts for \$61, and jissica bought 3 pairs of pants and 2 shirts for \$64. How much does 1 pair of pants cost? ~Please explain this problem to me

Math
60 - 24 = 36 points needed 36/4 = 9 questions needed right so n >/= 9

Precalculus
first do the complex conjugates (x+7i)(x-7i) = x^2 + 49 now the first two terms x^2-8x+16 now multiply using distributivee property x^2 ( x^2-8x+16 ) +49 ( x^2-8x+16 ) add

PHYSICS
50 = T1 cos 30 + T2 cos 60 T1 sin 30 = T2 cos 60

Physics
I guess 1 MJ means 10^6 Joules???? watts * seconds = Joules so 338 watts * time in seconds = 4.8*10^6 Joules t = 4.8 *10^6 / 338

Physics
http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/dopp.html

help math!
distance home to store = d total time = 1 hr d = 15 t d = 10(1-t) 15 t = 10 -10 t 25 t = 10 t = 10/25 d = 15* 10/25 d = 6 miles each waay total distance = 12 miles total time = 1 hour so average speed = 12 miles per hour BY THE way AXENMO averaging the speeds them selves is ...

help with math!
Very much like your other problem total distance = 15(40/60) + 10(20/60) = 10+10/3 = 40/3 miles in one hour = 13.3 miles per hour

Math
2/1.5 = 4/3 = 16/12 1.5/2 = 3/4 =9/12 1/3 = 4/12 No constant ratio in this whole scheme so no proportionality

physics
moments around pivot point at 20cm m(50-20)+50(30-20)=100(20-10) 3m + 50 = 100

physics question
m Ac = m v^2/r = 1700 * 400 / 55 Newtons

PHYSICS
8.88*9.81/.0454 = 1919 N/m if you really want kilo Newtons then 1.918 kN/m

physics
F = m v^2/r = m omega^2 r m = 20 v = 2 pi r/6.2 = 2 pi(1.8/6.2) r = 6.2 so solve for F, the mass times centripetal a mu = Ac/9.81 = (v^2/r) /9.81

Mathematics
(x-1) is the altitude I assume? if so (x-1)(1/2)(x+6+3x-4) = 119 (x-1)(4x+2) = 119*2 (x-1)(2x+1) = 119 2x^2 - x - 120 = 0 (x-8)(2x+15) x = 8

Just TEN cars 10 log 10 = 10 so ten dB for 10 times intensity so 90 db each

NO!!!!!
change in dB = 10 log base ten (intensity ratio) = 10 log (100) = 10*2 = 20 db for ten times intensity so 80 dB each

Algebra error repair
2 g t + g = 40 t (40 -2g)t = g t = g/(40-2g)

Physic
t is time for ball 2 t+1 is time for ball 1 h = (1/2)g (t+1)^2 h = 20 t + (1/2)gt^2 so g(t+1)^2 = 40 t + gt^2 g(t^2 + 2 t + 1) = 40 t + g t^2 2 gt + g = 40 t t = g (2t+1)/40 t+1 = answer to 1) etc

Math 120
first one: 4/10 second one 3/9 third one 2/8 fourth one 1/7 now multiply :) ------------------------ ow all good first one 6/10 second one 5/9 etc

Physics
energy at top = (1/2)m v^2 + m g h = 75 (25/2+9.81*7) energy at bottom the same but h = 0 so 75 (V^2/2) = 75 (25/2+9.81*7) (note-- the mass does not matter) Now if he comes up to the same height on the other side he will be moving up at 5 m/s (1/2)(25) = 9.81 h where h is the ...

wrong I think
V = Vi (0.82)^t not times t .75 = .82^t log .75 = t log .82 t = log.75 / log.82 = 1.45 years

angular accleration
Hey, I did one for you. Now you try.

angular accleration
150 - 120 = 30 rpm 30 *2pi/60 = pi radians/second = change in angular velocity pi/30 = angular acceleration in radians/second

MATH: Check my answers | HELP ASAP!!
12*23 = 276 yes

US History UGGGH
I am inclined to agree with you on d.

Maths
say tthey startedd east east distance = 150 + 120 cos 45 north distance = 120 sin 45 hypotenuse = sqrt[(150+120cos45)^2+(120sin 45)^2]

Maths
LOL try a+b+c = 3 try a = 1 b+c = 2 let b= 1 and c = 1 (1+1+1+1)(1+1+1+1) = 4*4 = 16

Physics
8.99*10^9[-32*10^-12 / 5.76*10^-4] = -49.9 *10^1 = -500 agree force is attractive (opposite signs). I guess you could call that negative.

Physics
v^2/R = 100/80

science, maths
the work done on a test charge q moving in an electric field is the force q*E times the distance moved IN THE DIRECTION of the force. The only direction that has NO component of force in the direction of motion is in the direction perpendicular to the force. The force is in ...

math
small = 47/22 - 11/22 = 36/22 = 18/11 large = small + 40/11

modern physics
I looked through this list of questions. They are cookbook questions and the recipes are in the student's text. for example if we know a half life in seconds and it is exponential decay then amount = original amount *e^-kt if amount/original amount = 1/2 then 1/2 = e^-kT ...

math question
.75*2400 = 1800 = value after first year .25*1800 = 450

American Government
Did Washington have a Health and Human Services department? A housing and Urban Development? .....

maths period help
when theta/4 = 2 pi you have gone once around the circle theta/4 = 2 pi theta = 8 pi

physics 1
Well, whatever we do we will be wrong because when you have a ship in water there is an effect called usually "added mass" due to having to accelerate water around the ship when you accelerate the ship. However your book did not know that so: F = m a -8*10^4 = 3.6*10...

Physics
The same as the original momentum.

Physics
sqrt(450^2+725^2) Hey - you are asking the same question over and over with different numbers.

math
864 - 702 = 162 You calculated how much she paid for the good deal but you were asked how much she SAVED.

math
75% off is 25% = 1/4 full price = 200*4 * 1.08 deal price = (200*3 + 50) * 1.08 subtract

Chemistry
17600 = 4.184 * 350 (T-24.1)

Math
70 (1- 1/14) = 70 (13/14)

gain per period = 1+r not per year gain per year = (1+r)^n gain per 6 years = (1+r)^6n

math
r = .035/n where n = times per year yearly gain = 1+r final amount = 2750 * (1+r)^6n so for example for 1000 times per year: r = .035/1000 = .000035 1+r = 1.000035 and amount = 2750 *(1.000035)^6000 = \$ 3392.60

incomplete statement
I assume it is sticking out horizontal from wall. I assume the weight is in the middle I assume the string is vertical, if not divide T by cos angle where angle is angle of string from vertical. moments about hinge 100 (1/2) -T (1) = 0 T = 50 N then you also need 50 N up at ...

physics
I mean I often answer physics questions here and you saved me a lot of work :)

physics
That was heroic Elsa tony !

sir damon steve damon damon help maths
integral T dt = .1 t^3 + 2 t^2 + 10 t at t = 12 = .1(1728) + 2(144) + 120 at t = 9 = .1(729) + 2(81) + 90 subtract value at 9 from value at 12 divide by (12-9)

Algebra
If 2x+1 = 5 then x = 4/2

The smallpox story was standard until very recently.

It is traditionally believed that smallpox was the killer, but recently that hypothesis has been challenged and cycles of drought and rainfall leading to waves of rodents carrying indigenous fevers might be the culprit. See: http://blogs.plos.org/publichealth/2013/07/30/guest-...

calculus
integral of F dx assuming that F is in exactly the direction of motion 7 integral dx/x^2 at 19 - at 1 -7 (1/x) at 19 - at 1 7/1 - 7/19 = 12/19

Social Studies
If you see a solution to the problem in that paragraph, you are magical. I have no doubt about the different religions, but by the way wonder about the claim of ethnic differences. What does that mean?

Science
1. right 2. right 3. WRONG X has greater energy/freequency, just below Gamma

History
...and this survivor of the Pearl Harbor attack is not happy either.

History
Of course it is correct! The others are just plain crazy. Admiral Mitscher is upset with you.

Physics
sorry 3/2 the way it is phrased

Physics
rotational: omega = v/r = angular velocity I = (2/3) m r^2 Ke = (1/2)I omega^2 = (1/2)m (2/3)mr^2 v^2/r^2 = (1/2)m (2/3)v^2 but translational Ke = (1/2) m v^2 so 2/3

chemistry
Do you have Google where you live?

Chemistry
delta U = heat in - work out delta U = Q - W in physics HOWEVER chem texts sometimes use delta U = Q + W with W = work IN so maybe that is what you have here. in that case if delta U is - then Q < -W heat in less than work out which is c)

Math
LOL :)

Math
-4 (4) < 4x < 5(4) -16 < 4x < 20 -16 + 5 < 4x+5 < 20 + 5 -11 < 4x+5 < 25

Math
proof read perhaps 30% of x is 87 ? .3 x = 87 x = 87/.3 = 870/3

Chemistry
heat comes out when you convert water to ice

physics!
Ac = v^2/R = omega^2 R well circumference = 2 pi R = 22.6 pi meters does that circumference in 16.6 seconds so v = 22.6 pi/16.6 meters/second so Ac = (22 pi/16.6)^2 / 11.3 the mass has nothing to do with it unless you want the tension in a string :)

Physics
leg of right triangle 5^2 + x^2 = 169 x^2 = 144 x = 12 this is a 5, 12, 13 right triangle

Accelerated Math
c = 7 s c depends on s

math
0.80 p = 65 p = 65/.8 = 650/8

math
(568+102-57) * 1.10 =

All subjects
EXPRESS all lengths in METERS, not cm for example I do not believe your well is radius of 3 cm Volume of well = V = pi r^2 * 21 Q = flow rate Q = width * depth * 2 m/s V = flow rate Q * time t

Chemistry
humm 2H2 + O2 ---> 2H2O O is 16 g/mol so O2 is 32 grams/mol so we have 384/32 = 12 mols of O2 That will yield 2*12 = 24 mols of H2O a mol of H2O is 2+16 = 18 grams/mol so 24 mols = 24*18 = 432 grams water

calculus
F = k x 4 = k (.1) k = 40 pounds/foot Energy = Work = (1/2) k x^2 = (1/2)(40)(.6)^2 foot pounds to get that with calculus work in = F dx = k x dx = k x^2/2 + constant if W = 0 when x = 0 than the constant is 0 so W = (1/2) k x^2

Physics
the wavelength is determined by the difference between high and low energy levels in the material emitting the photons.

Hope someone know this Math
The original reply that the terms are irrational is rational.

Math - Calculus
only if it is horizontal there. http://www.google.com/search?q=critical+point+of+function&ie=utf-8&oe=utf-8

Math
but I think you wanted GREEN (9/14) (70) = 45

Math
now try that 25/70 = ? 5/14 whew !!!

Math
another way multiply both sidees of this equation by the least common multiple of 14 and 70 I think 140 is close enough 140(5/14) = 140(x/70) 10 * 5 = 2 * x 5 * 5 = x 25 = x

math
yes

math
The area is four times the original and no I am retired.