Posts by Damon

Total # Posts: 31,029

Math
small = s and b = big s = b-2 1/s + 2/b = 5/12 so 1/(b-2) + 2/b = 5/12 agreed multiply by 12 b (b-2) 12 b + 24(b-2) = 5 b(b-2) 12 b + 24 b - 48 = 5 b^2 - 10 b 0 = 5 b^2 - 46 b + 48 0 = (b-8)(5b-6) so use b = 8 s = b-2 = 6

Physics
normal force = m g max static = .75 m g so m a = .75 m g for slide to start or a = .75 g now the slide a = .75 g v = a t 33 = .75 g t t = 33/(.75*9.81)

physics
m g h = m g (3.4/2)

Physics - Calculating work required
This is a problem about POTENTIAL! The path does not matter ! That is the whole point. The voltage potential difference is the difference in potential energy of a unit charge at the two voltages. work done = charge * change in V

Physics
force = 55*9.81 Newtons pressure = force/area if area is in meters^2 then force is in Pascals

physics
Vi = 110,000 meters / 3600 seconds v = Vi + a t at end, v = 0 so 0 = Vi -49 t t = Vi/49 then d = Vi t + (1/2) a t^2 d = Vi (Vi/49) - (1/2)(49)(VI^2/49^2) d = (1/2)Vi^2/49

Algebra
I worked it out in the way you are probably used to. Scroll down

Algebra
44+47 = ? mi/h time = 69/speed

Math
divide by 1,000 kg/tonne

arrgh upside down
.3456/.84 = .4114

too-hard probability sir damon/reiny/steve help
He did, right here: P(w ? 0) = 1 - P(b = 4) = 1 - .4^4 P(b = 2) = 6 * .4^2 * .6^2 =============================== prob of some white = 1-.4^2 = .84 the prob of 2 black = 6*.4^2*.6^2 = .3456 divide .84/.3456 so

too-hard probability sir damon/reiny/steve help
LOL use Scott's answer. I used 10 for number of trials, did not read correctly.

too-hard probability sir damon/reiny/steve help
I got .121/.929 = 0.130

too-hard probability sir damon/reiny/steve help
well using C(n,r) for 2 black p(b) =.4 p(not black) = .6 n = 10 r = 2 P(10,2) = C(10,2) .4^2 .6^8 C(10,2) = 10!/[8! 2!] = 10*9/2 = 45 so 45 * .16 * .0168 =.121 now for no whites, that is P of 4 blacks 6/10 * 5/9 * 4/8 * 3/7 = .0714 1-.0714 = .929 = probability of at least one...

Math HELP
A is 3,4,5 so right B is right C 36 + 289 = 400 ?? I think not D 12.25 + 144 = 156.25? Yes, so right

Typo
rho = 2.04 kg/5.1*10^-4 m^3 = 4 * 10^3 kg/m^3

Physics
Please proof read what you wrote. It has got to be backwards. the density of the cube I suppose :) displaces water weighing 5 Newtons 5 N = 1000 kg/m^3 * 9.81 * Volume so Volume = 5.1* 10^-4 m^3 mass = 20 N in air I think/9.81 = 2.04 kg so rho = 2.04 kg/5.81*10^-4 m^3 = 3.51...

Math question
The volume of something pointy with straight sides is the base area times the height divided by three. V = (1/3) pi r^2 h = (1/3)(3.14) (1)^2 (9) = 9.42 in^3 to get the value multiply by 2 = $ 18.84 so I agree

inverse correct - can not help with image
For inverse check multiply |0 +6| |-1/2 1/4| |4 12| |+1/6 +0 | = 1 0 0 1 so right ! I have no idea what the image is about

science
What you are looking at is essentially an adiabatic expansion of the air as the pressure goes down (It does not gain or lose heat.) In an adiabatic expansion the temp goes down. http://en.wikipedia.org/wiki/Adiabatic_process

science
http://www.engineeringtoolbox.com/air-altitude-temperature-d_461.html

science
Do you know about Coriolis? One way to think about it: 1. say you have a low pressure spot in the northern hemisphere. 2. a parcel of air south of that spot will head north, toward the low pressure. 3. That parcel was moving east at the speed of the earth surface at that ...

Math
yes there are tricks to do these in your head like 15% is 10% + 5% 12.5 * 2 = 25 5% = (1/2) 10% etc

Math
(1/6)(1/2) = 1/12

same question over and over and over
delta L /L = k * delta T

Math
I you have two 25 degree angles in a triangle, the third one must be 130 degrees

Math
I guess you mean the two equal angles are each 25 since the sum must be 180 50 + x = 180 x = 130

tecca math
5,237

huh?
What do you mean? Are you missing parentheses or something?

Logarithms
x^log3(x) = 3^9 log3 (x^log3(x) = log3(x) log3(x) = 3^9 log3 (x) = 3^(9/2) = 3^4.5 = 140.3 3^log3(x) = x = 3^140.3 check my arithmetic, did quickly

Logarithms
2 log8 (8) - .5 ln (e) 2 - .5 = 1.5

Logarithms
log8 (5^8) - log8(7) = log8 (5^8/7)

algebra
yes

algebra
3x^2 - 5x + 2 = 0 a = 3 b = -5 c = +2 So I think the last one. if they ask for zeros (3x-2)(x-1) = 0 x = 2/3 or x = 1

maths
70*44*3 = 6 * pi (17.5)^2 t t = 70*44*3/[6*pi*17.5)^2] seconds divide by 3600 to get hours

math
train 1, x= 45*3 = 135, y = 0 dx/dt = 45 train 2, x = 0, y= -60*3 = -180 dy/dt = -60 z = hypotenuse z^2 = x^2+y^2 = 3^2 (45^2+60^2) = 3^2 (2025 + 3600) = 3^2(5625) so z = 3*75 = 225 z^2 = x^2 + y^2 2 z dz/dt = 2 x dx/dt +2 y dy/dt dz/dt = (xdx/t+ydy/dt)/z = (135*45-180*-60)/...

algebra
cos 75 = x/15

maths
L = 6 + 2 p W = 4 + 2 p 56 = (6+2p)(4+2p)-6*4 56 = 24 + 20p + 4p^2 -24 4 p^2 + 20 p - 56 = 0 p^2 + 5 p - 14 = 0 (p+7)(p-2) = 0 p = 2

maths
2 see above http://www.jiskha.com/display.cgi?id=1487067037

Math
4 b + 5 y = 49 2 b + 1 y = 17 4 b + 5 y = 49 10b + 5 y = 85 -----------------subtract -6 b = -36 b = 6

Math 115
6*1/2 = 3 while you rest 3 + (1/60 mile/min)(t-40)

physics
k Q1 Q2/ d^2

Math
to multiply by 100 while driving without a calculator: Stop the car by the side of the road. Move the decimal point two spaces to the right. Resume driving.

Math
42 animals 18-6 = 12 female cats prob of female cat = 12/42 now we have 41 animals, 11 females cats prob of female cat = 11/41 so 12/42 * 11/41

Math
-6x + 6 +3x = -3x + 6

Math
a + s = 220 7 a + 5.5 s = 1390

Math/pre-algebra
(.25 in / 6 ft) is our conversion factor 18 ft (.25 in/6 ft) = .75 in 66 (.25/6) = 11/4 204 (.25/6) =

Needs Chemistry
Not my thing, sorry

Physical Science
O has 8 protons and 8 neutrons. normally it has 8 electrons as well when it is neutral HOWEVER if it has a charge of +1 (unusual for O by the way) then it lost one of those 8 electrons and is left with 7

calculus
find y at the end (x = 10) find y at the beginning (x=3) subtract Yend - Ybegin divide that by 10-7 which is 3

Physical Science
You are welcome.

Physical Science
If it were A, it would be black :) If it were C, it would emit the transition spectra of the metal If it were D, yu would not see it at all :) So I think we pick B, which contains the handy word "reflect".

physics
during the stop, which starts at 20 and ends at 0, the average angular velocity is 10 rad/s 1 rev = 2pi rad 15.92 revs = 2*pi*15.92 rad so 2 pi * 15.92 rad/10 rad/s = about 10 s, yes I agree with teacher

calculus
I am a physicist so call your y "v", velocity and your x is "t" d = integral v dt d is integral from 1 to 5 of (t^2 -9) dt = t^3/3 - 9t at 5 - at 1 at 5 it is 125/3 - 45 at 1 it is 1/3 - 9 -------------------subtract 124/3 - 36

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

physics
forget cm, doing seconds and meters - SCI units Pe = (1/2) k |x|^2 Ke = (1/2) m |v|^2 so for Ke = 1/2 Pe m |v|^2 = .5 k |x|^2 but ?^2 = k/m so |v|^2 = .5 ?^2 |x|^2 At our spots [A ? cos ?t]^2 = .5?^2[A sin ?t]^2 A^2 ?^2 cos^2?t = .5?^2 A^2sin^2wt cos^2 ?t = .5 sin^2 ?t cos^2 ?...

p
I already did one like this for you.

physics
.35 meters in half a period, T/2 2 A = .35 x = A sin 2 pi f t x = A sin (2 pi t/T) max at T/4 min at 3T/4 3T/4 - T/4 = time between max and min = T/2 so 0.30 m/s = 0.35 m /(T/2)s T/2 = 0.35/.3 T = 7/3 seconds w = ang freq = 2pi/T = 6 pi/7 max a = w^2 A = (6pi/7)^2(.35/2) max v...

physics
I took this course in 1955 and no longer need practice. You are asking basically the same question over and over. I am happy to help but have done enough of them for you. since it is not extended at the start use y= A cos 2 pi t/T which is A at t = 0 and hits the lowest point...

physics
Hey, you do some now !

Social Studies
This is much more how I remember it: http://www.georgiaencyclopedia.org/articles/government-politics/worcester-v-georgia-1832

Social Studies
That decision I just looked up is not how I remember it in fact. I thought the Supreme Court sided with the tribes and Andrew Jackson kicked the tribes west anyway. Yes, what the above says is that white settlers can not be prohibited from trespassing on native property.

Social Studies
from Google: 515 (1832), was a case in which the United States Supreme Court vacated the conviction of Samuel Worcester and held that the Georgia criminal statute that prohibited non-Native Americans from being present on Native American lands without a license from the state ...

physics
sqrt (37^2+44^2) = 57.49 = 57 meters tan angle = 44/-37 angle = -50 x is - and y is + so second quadrant 180 - 50 = 130

Geometry
another one?

Math
e^0.018t = 20/12 .018 t = ln (20/12) = .511 t = 28.4 years

physics
ke = (1/2)(5.4) (6.2)^2 stops so all ke converted to U U = m g h = ke from first part 5.4 (9.81) h = answer from part 1

physics
d = (1/2) a t^2 8 = .5 a (16) so a = 1 m/s^2 v = a t = 1 (4) = 4 m/s or use head like this average speed = 8 m/4s = 2 m/s begin speed is zero so final speed = twice average speed = 2*2 = 4 m/s

math algebra
log x^n = n log x so you have log x (1+2+3+4 ...120) so log x times arithmetic sequence sum with a = 1, d = 1 n from 1 to 120 see http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html

Algebra
|3y+4| means absolute value of 3y+4 -| means nothing to me.

huh
typo ?

physics
1 m^2 = 10,000 cm^2 20 * 10,000 = 200,000 N/m^2 400 cm^2 = 400/10,000 = .04 m^2 200,000 * .04 = 2000*4 = 8,000 N of weight about 800 kg mass if g = about 10m/s^2, small car :)

math
I said "which it is".

math
I suspect they mean every diameter of a circle is a chord, which it is.

Math
no 2 * 96 / .75 is not 640

Ecconomics
so you want the intersection? 15 - .2 p = -3 + .4 p .6 p = 18 p = 180/6 = 30 q = -3+12 = 9

Math
300 (1.00) - 300 (0.05) = 300 (0.95) = 285

is it falling?
if so then v = -gt d = -(1/2) g t^2 from second two to second three: d = -(1/2)g (9-4) = -(5/2) g from second three to second four: d = -(1/2)g (16-9) = -(7/2) g ratio = 7/5

ed tech
The software on this site does not allow copy and paste.

ed tech
You can not do that, sorry.

Algebra
diver 1 depth = 12 - 1 t diver 2 depth = 15 - 2 t so 12 - t = 15 - 2 t t = 15-12 t = 3 seconds 12 - t = 12 - 3 = 9 meters

ART
The only one I am familiar with is his painting of George Washington. That certainly is a formal soldier. This link is to another type of soldier but at least his head looks red: http://www.google.com/search?q=gilbert+stuart+painting+of+soldier+red+hair&tbm=isch&tbo=u&source=...

projectile motion
Nothing to do with the mass. I assume you mean 60 degrees from horizontal in which case the initial vertical velocity component is 5 sin 60 = 4.33 v = 4.33 - 9.81 t at top v = 0 so t = 4.33/9.81 = .441 seconds upward bound h = 4.33 t - 4.9 t^2 for range use 2 t (upward and ...

Science
two problems connected only by falling time vertical problem: Vi = initial y velocity = 0 v = Vi - g t h = Hi + Vi t - .5 g t^2 so at ground 0 = 0.6 + 0 - 4.9 t^2 t^2 = 0.6/4.9 t = 0.35 s to fall v at ground = 9.81* 0.35 horizontal velocity = 2.4 until it hits range = 2.4 * .35

Algebra
3 a + 9 c = 183 6 a + 13 c = 276 multiply first equation by 2 6 a + 18 c = 366 6 a + 13 c = 276 ---------------- subtract 5 c = 90 c = 18 etc

Math
32/8 1*8 = 8 2*8 = 16 3*8 = 24 4*8 = 32 5*8 = 40 6*8 = 48 7*8 = 56 8*8 = 64 9*8 = 72 10*8= 80

English
Is that chair related to you? Or is that the stairs groaning like your baby coyote?

Science
initial T = 0+273 P V= n R T same n and R so 2P * 2V = n R (4T) 4*273 = 1092 K which is 1092-273 = 819 C

physics
in Part A y = Vi t - 4.9 t^2 30 = Vi(2)- 4.9(4) 2 Vi = 49.6 Vi = 24.8 agreed Part B 15 = 24.8 t - 4.9 t^2 4.9 t^2 - 24.8 t + 15 = 0 t = [ 24.8 +/-sqrt(24.8^2-4*4.9*15) ]/9.81 =[24.8+/- 17.9]/9.81 use smaller t for on the way up .702 seconds

physics
I am not going to just do these for you in general magnitude = sqrt (xcomponent^2+ycomponent^2) tan angle from x axis = ycomponent/xcomponent) to do A + B say C = (Ax+Bx)i + (Ay+By)j where i and j are unit vectors in x and y directions

Physiscs
If it passes through the bar along the axis of the bar, the moment of inertia is small because the mass is close to the axis of rotation. Remember that mR^2 stuff. It is not zero though unless the radius of the bar is zero :) It is in fact a slender solid cylinder and its ...

Physics
Trace ray from the top of A and then another from the bottom of A

Physics
identical

physics
reaches top 3.6/2 or 1.8 seconds after launch at top, v = 0 but v = Vi - g t in meters, seconds g = 9.81 m/s^2 so 0 = Vi -9.81 t 0 = Vi -9.81*1.8 Vi = 17.7 meters/second

math
1.02 x = 7150 so x = 7150/1.02

maths
2*20 =

pre calc
top = L^2 bottom = L^2 4 sides = 4*13L total = 2 L^2 + 52 L

algebra
Good ! You are welcome.

algebra
no, look below carefully 3.2*10^2 LY ( 5.88*10^12 mi/LY) = 18.8 * 10^14 mi = 1.88 * 10^15 mi

easy algebra question, check answer
yes 3*10^1 * 3*10^5 = 9*10^6 because x^a * x^b = x^(a+b)

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