Monday
February 20, 2017

Posts by damon

Total # Posts: 29,360

Physics
1/d^2
February 17, 2017

algebra
e^[2(3x^2-2)]
February 16, 2017

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
February 16, 2017

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)
February 16, 2017

physics
m g h = m g (3.4/2)
February 16, 2017

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
February 16, 2017

Physics
force = 55*9.81 Newtons pressure = force/area if area is in meters^2 then force is in Pascals
February 15, 2017

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
February 15, 2017

Algebra
I worked it out in the way you are probably used to. Scroll down
February 15, 2017

Algebra
44+47 = ? mi/h time = 69/speed
February 15, 2017

Math
divide by 1,000 kg/tonne
February 15, 2017

arrgh upside down
.3456/.84 = .4114
February 15, 2017

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
February 15, 2017

too-hard probability sir damon/reiny/steve help
LOL use Scott's answer. I used 10 for number of trials, did not read correctly.
February 15, 2017

too-hard probability sir damon/reiny/steve help
I got .121/.929 = 0.130
February 15, 2017

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...
February 15, 2017

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
February 15, 2017

Typo
rho = 2.04 kg/5.1*10^-4 m^3 = 4 * 10^3 kg/m^3
February 15, 2017

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...
February 15, 2017

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
February 15, 2017

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
February 15, 2017

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
February 15, 2017

science
http://www.engineeringtoolbox.com/air-altitude-temperature-d_461.html
February 15, 2017

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 ...
February 15, 2017

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
February 14, 2017

Math
(1/6)(1/2) = 1/12
February 14, 2017

same question over and over and over
delta L /L = k * delta T
February 14, 2017

Math
I you have two 25 degree angles in a triangle, the third one must be 130 degrees
February 14, 2017

Math
I guess you mean the two equal angles are each 25 since the sum must be 180 50 + x = 180 x = 130
February 14, 2017

tecca math
5,237
February 14, 2017

huh?
What do you mean? Are you missing parentheses or something?
February 14, 2017

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
February 14, 2017

Logarithms
2 log8 (8) - .5 ln (e) 2 - .5 = 1.5
February 14, 2017

Logarithms
log8 (5^8) - log8(7) = log8 (5^8/7)
February 14, 2017

algebra
yes
February 14, 2017

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
February 14, 2017

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
February 14, 2017

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)/...
February 14, 2017

algebra
cos 75 = x/15
February 14, 2017

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
February 14, 2017

maths
2 see above http://www.jiskha.com/display.cgi?id=1487067037
February 14, 2017

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
February 14, 2017

Math 115
6*1/2 = 3 while you rest 3 + (1/60 mile/min)(t-40)
February 14, 2017

physics
k Q1 Q2/ d^2
February 13, 2017

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.
February 13, 2017

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
February 13, 2017

Math
-6x + 6 +3x = -3x + 6
February 13, 2017

Math
a + s = 220 7 a + 5.5 s = 1390
February 13, 2017

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) =
February 13, 2017

Needs Chemistry
Not my thing, sorry
February 13, 2017

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
February 13, 2017

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
February 13, 2017

Physical Science
You are welcome.
February 13, 2017

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".
February 13, 2017

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
February 13, 2017

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
February 13, 2017

Stat
http://davidmlane.com/hyperstat/z_table.html
February 13, 2017

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 ?...
February 13, 2017

p
I already did one like this for you.
February 13, 2017

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...
February 13, 2017

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...
February 13, 2017

physics
Hey, you do some now !
February 13, 2017

Social Studies
This is much more how I remember it: http://www.georgiaencyclopedia.org/articles/government-politics/worcester-v-georgia-1832
February 13, 2017

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.
February 13, 2017

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 ...
February 13, 2017

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
February 13, 2017

Geometry
another one?
February 13, 2017

Math
e^0.018t = 20/12 .018 t = ln (20/12) = .511 t = 28.4 years
February 13, 2017

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
February 13, 2017

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
February 13, 2017

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
February 12, 2017

Algebra
|3y+4| means absolute value of 3y+4 -| means nothing to me.
February 12, 2017

huh
typo ?
February 12, 2017

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 :)
February 12, 2017

math
I said "which it is".
February 12, 2017

math
I suspect they mean every diameter of a circle is a chord, which it is.
February 12, 2017

Math
no 2 * 96 / .75 is not 640
February 12, 2017

Ecconomics
so you want the intersection? 15 - .2 p = -3 + .4 p .6 p = 18 p = 180/6 = 30 q = -3+12 = 9
February 12, 2017

Math
300 (1.00) - 300 (0.05) = 300 (0.95) = 285
February 12, 2017

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
February 12, 2017

ed tech
The software on this site does not allow copy and paste.
February 12, 2017

ed tech
You can not do that, sorry.
February 12, 2017

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
February 12, 2017

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=...
February 12, 2017

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 ...
February 12, 2017

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
February 12, 2017

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
February 12, 2017

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
February 12, 2017

English
Is that chair related to you? Or is that the stairs groaning like your baby coyote?
February 12, 2017

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
February 12, 2017

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
February 11, 2017

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
February 11, 2017

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 ...
February 11, 2017

Physics
Trace ray from the top of A and then another from the bottom of A
February 11, 2017

Physics
identical
February 11, 2017

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
February 11, 2017

math
1.02 x = 7150 so x = 7150/1.02
February 11, 2017

maths
2*20 =
February 11, 2017

pre calc
top = L^2 bottom = L^2 4 sides = 4*13L total = 2 L^2 + 52 L
February 10, 2017

algebra
Good ! You are welcome.
February 10, 2017

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