# Posts by Damon

Total # Posts: 29,823

Math
maybe 1002001 ? That is a lot of km 2000 km / (35 + 48 + 45.5) = 15.56 km/L = 6.43 L/100 km

physics
http://www.physicsclassroom.com/class/sound/Lesson-5/Closed-End-Air-Columns

Physics Force and Friction question
max static friction force = .4*981 which is more than 350 so It stays in place. 350 N might be enough to keep it moving, but is not enough to start it.

Is it barely not moving, is it moving at constant velocity, is it accelerating?

A = 3 x + 59 + 2*35 = 3x + 129

physics
oh my, still in feet? in this case g = about 32 ft/s^2 v = 58 - 32 t at top t = 0 t at top = 58/32 seconds total time in air by the way = 2 t = 58/16 seconds now the problem: h = Vi t - .5 * 32 t^2 H = 58 (58/32) - .5 * 58^2/32 (A.) H = 58^2/64 ft (B.) 2 t = 58/16 sec when h...

ah 4 8 16 32 64

4*2^n n = 4 quarters of and hour 2^4 = 16 so 4*16 = 64

Science/Math
If it did not float then 5 mL

Math
well, I am inclined to multiply first equation by 4 and second by 3 -56 x + 60 y = 12 +63 x - 60 y + 30 ------------------- add 7 x = 42 so x = 42/7 then -14(42/7) + 15 y = 3 -84 + 15 y = 3 15 y = 87 y = 87/15 ========================= try that in the second one to check 21(42...

Social Studies
Just for fun: http://www.nationalgeographic.com/travel/top-10/ancient-highways/ http://www.bbc.com/news/magazine-33291373

Social Studies
Did historical Japan have good roads? Did the Incas? How were each governed? How did they communicate with other nations?

Math
g = number of girls 5g/7 = number of boys g - 5g/7 = 120 2g/7 = 120 g/7 = 60 g = 420 then boys = (5/7)420 = 300 and 420 + 300 = 720 total

chemistry
Do you mean in catalytic converter? Maybe read "types" section in here: http://en.wikipedia.org/wiki/Catalytic_converter

Math
using common denominator of 18: 10/18 , 7/18 and 9/18 Now you rearrange them.

physics
2.9*9.81 Newtons

chemistry
A certain wavelength or frequency corresponds to a certain photon energy which is a certain change of energy of the electron shell around the atom. In other words the frequency tells you how an electron orbit changed.

calculus
dh/dt = -9.8 t + 10 when t = 1 dh/dt = 10-9.8 = 0.2

math
x y change in y/change in x which is slope -2 9 ****** -5 -1 4 ****** -5 0 -1 ****** -5 1 -6 ****** -5 2 -11 hmmm, constant slope = -5 y = -5 x + b 9 = -5 (-2) + b 9 = 10 + b b = -1 so y = -5 x -1 answer check at last point -11 = -5(2) -1 -11 = -10 - 1 yes, good

Cousino
speed upstream = 8 - u speed downstream = 8 + u time upstream = 5/(8-u) time downstream =5/(8+u) so 5(8-u) + 5/(8+u) = (4/3) hr 5(8+u) + 5(8-u) = (4/3)(64-u^2) 15(8+u) + 15(8-u) = 256(64-u^2) etc, solve quadratic

be careful with parentherses
do you mean 1/(2a) or (1/2)a 1) f(-2) = 4 a^2 +2a + 3b = 4 a^2-b+8 f(-3) = 9 a^2 +3a + 3b = 7a^2-b+14 so 2 a + 3 b = - b + 8 2 a + 4 b = 8 a + 2 b = 4 or a = 4 - 2 b and then 2 a^2 + 3 a + 4 b = 14 2(16 - 16 b +4b^2) + 3(4-2b) +4b=14 32 -32b +8b^2+12 -6b +4b = 14 30 + 8b^2 -...

physics
v = velocity up = 30 sin 30 - 9.81 t u = velocity horizontal = 30 cos t if t = 1 v = 15 - 9.81 u = 30(.866) speed = sqrt (u^2+v^2) tan angle up = v/u

math
as y--->0 cos y = 1 - y^2/2 + ........ numerator: 2 - 1 +(1/2)(9)x^2 -1 +(1/2)(16)x^2 0 + (25/2)x^2 oh my now divide by x 25 x/2 goes to 0 as x goes to 0

math
by the way tangent of small angle approaches sine of that small angle :) theta + theta^2/2 .......

math
Hey, I did the other one, try series approach on this one too.

math
m = math only s = science only b = both = 10 31 = m + b = m + 10 so m = 21 s+b = 36 - m s + 10 = 36 - 21 s + 10 = 15 so = Answer all science students s = 5 only science ======================== check 21 + 10 = 31, yes all math students 5 + 10 = 15 , yes all science students 21...

Pre-calculus
This is what it is about: http://www.youtube.com/watch?v=zw0waJCEc-w sin 45 = (1/2)sqrt 2

Pre-calculus
well, 7 = 6 + 1 so it is really sin (6 pi/12 + pi/12) sin(a+b) = sin a cos b + cos a sin b (just like your other problem) sin 6 pi/12 = sin 90 = 1 cos pi/12 = cos 15 deg cos 90 = 0 so cos 15 degrees

Math
y = k/x^3 new y = k/(x/2)^3 = 8 k/x^3 8 times as big

english
I have made 100 ship models in my life. I had made 100 ship models when they told me to stop and start doing physics problems.

Maths
9 km/(3/2)hr = 18/3 = 6 km/hr

6/8 = 60/80 8/10 = 64/80

Math
2 driveways/day * 5 d/w = 10 driveways/week 10 driveways/week * 50 work weeks/yr = 500 driveways/year Now as Myah said, what is the question?

physics
heat of fusion * 150 g + 150 * heat capacity* (T-0) = 300 * heat capacity*(50-T)

Physics
normal forces 5 kg block: 5(9.81) 10 kg block 5*9.81 and 15*9.81 forces 5 kg block .2 * 5 * 9.81 right T left no acceleration so T = .2 * 5 * 9.81 = 9.81 N (answer to part C by the way) 10 kg block T left .1 * 15 * 9.81 left 45 N right so 45 - 9.81 - .1*15*9.81 = 10 a the end

physics
h = 1 = (1/2)(9.81)t^2 (a)solve that for t, the fall time u t = 1.5 (b)so u = 1.5/t v = g t = 9.81 t speed = sqrt (u^2+v^2) tan angle below hor = |v|/u

y = k x -12.5 = 50 k -25 = 100 k k = -1/4 y = -x/4 y = - (47/4) / 4 = - 47/16

math
(5)(3/13) - 2(10/13) = -5/13 You better stay away from this game. There are 13 cards in each suit of which 3, the jack, queen and king are winners. The other 10, ace through 10, are losers

Physics
If it is moving to the left, the frictional force is pushing right. 0.6 * 90 * 9.81 yes, looks about right but stick to 3 significant figures.

algebra
(0,13) (13,0) and (0,0) completes triangle that is half a 13 by 13 square area = 169/2

environmental science
Ah, almost but your understanding of feedback is backwards. Negative feedback means the output is fed back and inhibits further growth in the output, stable Positive feedback means the output is fed back and INCREASES growth in the output, UNSTABLE. This is what they are ...

environmental science
well, I guess natural gas is higher quality than most of what you find in a landfill :) It all depends on their definition of "near" the surface though.

History
LOL - yes, stamps and tea are different from each other.

Physics
total energy at top = (1/2)(1530)(36) + 1530(9.81)(115) total energy at bottom = (1/2)(1530)(27)^2 work done = energy at top - energy at bottom average velocity = (27+6)/2 time = 4400/average velocity power = work done/time

Statistics
binomial distribution p(n,k) = C(n,k)p^k (1-p)^(n-k) p(3,1) = C(3,3) .38^3 * .62^0 = 1 * .38^3 * 1 do c next because b is 1 - c p(3,0) = 1 * 1 * .68^3 now b = 1 - c = 1 - .68^3

Science
The word "compound" is a dead giveaway.

Physics
ice is about 2.03 Joules/ gram deg c so 2030 J/kg deg c 1.2 kg *2030 J /kg degC (-15-T) = 20,000 J

Physics
v cos 30 = 110

Chemistry
.37* 500 = .96 x where x is the amount of strong stuff you put in 500 - x is the amount of water

Science
which answer uses the word "compound"?

-1/2 = -3/6 +1/3 = 2/6 does that help ?

Differential Calculus
find radius of surface as a function of height h r/h = 5/10 = .5 then surface area = pi r^2 = pi (.25 h^2) change in volume dv = surface area * dh dv = pi (.25 h^2) dh and dv/dt = .25 pi h^2 dh/dt 4 = .25 pi (9) dh/dt solve for dh/dt

algebra 1
50 mi/h * 5280 ft/mi *1 h /3600 s mi cancels h cancels we are left with 50 * 5280/3600 ft/s = 73 ft/s

error !
french alone = f history alone = h both = 8 f+8 - 10 = h+8 or f-h = 10 and f+h + 8 = 40 or f+h = 32 so 2f =42 f = 21 h = 11 so f+8 = 29 study french or both h+8 = 19 study history or both

Venn Diagram
french alone = f history alone = h both = 8 f+8 - 10 = h+8 or f-h = 8 and f+h + 8 = 40 or f+h = 32 so 2f =40 f = 20 h = 12 so f+8 = 28 study french or both h+8 = 20 study history or both

American Governement
I would be inclined to favor A, balance of power.

American Governement
Yes, right, A

Chemistry
.12 * 207 grams

value
(1/2)(100)(64) Joules

Chemistry
LOL, not observable I am sure h/(mv) = 6*10^-34 / (.05*40)

Math
Two problems: 1. x-8 -15 = -6 2. -x+8 -15 = -6

algebra
3000 = 1000 e^10 k 3 = e^10k ln 3 = 10 k solve for k n = 1000 e^5k with same k do e^5k on your calculator

social studies
They are in it !!!

Math/ Algebra
I did not miss a sign. 1/3x is not x/3

Math/ Algebra
well, if it is actually 14 = (1/3) x + 5 or 14 = (x/3)+ 5 then that is 14 = (1/3)27 + 5 14 = 9 + 5 yes however 14 is not 1/ (3*27) + 5

Math
m marbles in bag 2m/5 are red so 3 m/5 = b+y m = r + b + y b/y = 5/7 or y = 7b/5 3 m/5 = b + 7b/5 3 m/5 = 12 b/5 4 b = m b = (1/4) m

physics
I gave you the frequency and the rotational speed because I do not know what "rotational frequency" means.

physics
v^2/r = 6 m/s^2 so v^2 = 86.5 *6 v = sqrt (86.5*6) T = pi d /v = pi(173)/sqrt(86.5*6) f = frequency = 1/T omega = 2 pi f = 2 pi/T = 2 sqrt(86.5*6) / 173

Science
no F = m a big F is big m times big a

TECH ED HELP
I agree with kara.

Math
agreed on the first 2, there is no answer for number 2 but the third 2y = 2x-6 y = x-3 slope = 1 your -3 is b in y = m x + b, the y axis intercept

Calc I (@Reiny)
Reiny already did this for you. Yes, right.

physics
vertical force = m g - F sin 38 horizontal force =.42*vertical force - F cos 38 when the horizontal force is zero, it is about to accelerate so when F cos 38 = .42 (85*9.81-F sin 38) solve for F

math
3/24 = 1/8 = .125

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

ashworth

computer
LOL, this depends on the level of detail. I am not going to do an entire flow chart for Turbotax deluxe :)

chemistry
to raise the temperature of 1 kg of Aluminum one degree centigrade you must put in 900 Joules of heat energy.

math(Quantitative) ...Pls help me
(b) maybe time of year, exchange rate for currency

math(Quantitative) ...Pls help me
well, your guess is as good as mine but (a) number of football games, depth of snow (b) Legon Ghana? (c) number of hurricanes in past 12 months, number of arrests of bank officers (d) month of the year, number of weddings scheduled for week

Maths
(1/2) g/cm^3 or 500 kg/m^3

chemistry

math
pi/2 3 pi/2 and I suppose -pi/2 -3 pi/2

math
so she buys all red ribbon ! 20/1.59

Physics
zero, it came back

physic
.5 (840)(T-16) = 2(4200)(25-T)

Physics
zero Displacement is a VECTOR this ball moved up, then down. It therefore moved zero meters in no direction. They did NOT ask for DISTANCE

Math
C(16,4) = 16! / [ (16-4)!(4!) ] =16*15*14*13/(4*3*2) = 4 * 5 * 7 * 13 = 1280 Oh well

math
21/2 = 10.5 so try 10 + 11

physics
143 = m g + m a = m (9.81+0.762) m = 143/(9.81+.762) weight = m g

physics
g(Re/r)^2 = (1/4)(9.81)

physics
6.5 * 10^5 I expect you mean and 1.8*10^7 F = m a 6.5 * 10^5 = 1.8*10^7 a a = 3.61*10^-2 m/s^2 90 km/h (1 h/3600s)(1000 m/km) = 25 m/s v = a t 25 = 3.61*10^-2 t t = 6.93 *10^2 s = 693 s = 11.5 min

Interferometry carried to an unimaginable (for me) extreme
You better Google LIGO, but that is the whole thing. There is no simple reply really.

physics
6 g - T = 17 a T - mu(11 g) = 11 a what is a? d = (1/2) a t^2 1 = (1/2)a(1.48)^2 a = .913 m/s^2 6 g - T = 15.5 so T = 6 g - 15.5 so 6 g - 15.5 - 11 g mu = 10.0 let g = 9.8 and solve for mu

Math
LOL, cost / number of sprays

physics
vertical: Ftop = mg + Tt = m v^2/R Fbot = Tb-mg = m v^2/R so max is Tb = m g + mv^2/R so mg +Tt = Tb-mg 2 mg = Tb-Tt LOL, could have guessed Horizontal T = m v^2/R given Tb = 1.066 T mg + mv^2/R = 1.066 mv^2/R g = .066 v^2/R so v^2 = g R /.066

Maths
one at x = 0 then 10 more at 5, 10, 15, 20, 25 , 30, 35, 40, 45, 50 You always have one more fence post than panels of fencing

Maths
50/5 + 1 = 11 (one is at x = 0)

Social Sudies
fishing if the ^%\$&* feds would let you fish.

physics
I do not see the figure but am at a loss to understand how the ledge has anything to do with it unless he hits it. u = 17 m/s until splash Vi = 0 h = 7.9 m h = 4.9 t^2 so t = 1.27 seconds v = 9.81 t = 9.81*1.27 = 12.5 m/s speed = sqrt (17^2 + 12.5^2)

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