Wednesday
September 28, 2016

Posts by Damon

Total # Posts: 27,171

Chemistry
choices A. H>0, S>0 , G<0 B. H<0, S>0 , G<0 C. H>0, S>0 , G>0 D. H<0, S<0 , G>0
July 16, 2016

Chemistry
Marcela dissolves 80.0 g of ammonium nitrate in 50.0 mL of water at room temperature and notes that the temperature of the solution decreases by 5.0°C. Which correctly designates the signs of changes of G, S and H for this reaction?
July 16, 2016

Missing data for binomial distribution problem
We need to know how many she planted. Given n, use binomial distribution with p = 0.95 and 1-p = 0.05
July 16, 2016

math
http://www.jiskha.com/display.cgi?id=1468692682
July 16, 2016

math
red each is 3/20 green each is 4/40 which is 1/10 so 10(3/20) + 50(1/10) = 1.50 + 5.00 = 6.50 ah well, not on the list. Typo?
July 16, 2016

math
let me see 5 7 11 13 I think mean = (5+7+11+13)/2 = 36/4 = 9 median = (7+11)/2 = 9 When there are an even number of items it is impossible to pick the same number above and below any particular one. Therefore you take the average of the two middle ones.
July 16, 2016

physics
original is r v = 5 r then later same v = 4 (r+2) so 5 r = 4 r + 8 r = 8 ohms
July 16, 2016

no, physics :)
9 because 3^2 = 9 or because 3 s has 1 3 p has 3 3 d has 5 and 1 + 3 + 5 = 9 Note, each of those orbits can have electrons with spins of + or - 1/2 so total of 18 electrons for n = 3
July 16, 2016

statistic
3 b 2 b, 1 g 1 b, 2 g 3 g so 4 possible outcomes, all equally likely p of each is .25
July 15, 2016

Geometry
6.75 in (1 ft/.25 in) = 27 ft 4.50 in (1 ft/.25 in) = ?????
July 15, 2016

calc
Angle to what? Not knowing do not know sin or cos F (cos 48 or sin 48)(0.45) = 175
July 15, 2016

Physics
Ah yes, just noticed you said 5, good
July 15, 2016

Physics
C =q/V so x = q/68 that q is all the charge we have now for both capacitors total C = 12*10^-6 + x q = 20 (12*10^-6 + x) 68 x = = 240*10^-6 + 20 x 48 x = 240 * 10^-6 x = 5 *10^-6 Farads or 5 µF
July 15, 2016

You are right, impossible
Force is change of momentum / time = change in m v / t You have to know the time
July 15, 2016

Physics
horizontal speed u = 30 forever so what is vertical speed v? v = g t v = 9.81(3) that is also around 30 m/s so speed = sqrt(u2+v^2) = sqrt 1800) = about 42 do it all better with calculator
July 15, 2016

physics
Tricky pulse speed increases as you toward center at every r, acceleration, a, which is like a variable g for us a = omega^2 r This is like the plse on a hanging rope problem see: http://www.usna.edu/Users/physics/mungan/_files/documents/Scholarship/HangingPulse.pdf
July 15, 2016

physics
Suspect speed is 33.3 m/s average speed during stop = 33.3/2 =16.65 time to stop = t = 30/16.65 = 1.80 s d = .5 a t^2 30 = .5 a 1.8^2 so a = 18.5 m/s^2 so F = m a = 1000*18.5 = 18,500 Newtons
July 15, 2016

Math
so 11 girls, so what is the question?
July 15, 2016

hey, I do not need this much practice, already passed subject
now wait a minute, this is too much like the last one. You try for a while. I already know how.
July 14, 2016

physics
Well, now we seem to be back in the dark ages of some king's feet. v1 = 42*5280/3600 ft/s v2 = 58*5280/3600 ft/s assuming constant acceleration we can use average v va = 50*5280/3600 ft/s so t = 660/va a = (v2-v1)/t
July 14, 2016

physics
26.8 m/s = 60 mph You do not say but I assume you mean 60 mph or 26.8 m/s v = a t 26.8 = a (3.2) a = 26.8/3.2 d = (1/2) a t^2 = .5 (a) (3.2)^2
July 14, 2016

Math
I guess you mean log base b of a = c log a = c b^(log a) = a = b^c if a<1 and b >1 then fraction = big number^c hmm it would be helpful if c <0 like fraction = b^c = 5^-2 = 1/25 if a<0 and b >1 then logb (-something) oh my, we are trying to take the log of a ...
July 14, 2016

Math
You are welcome.
July 14, 2016

Math
d = 2 n q = .5 n 5 n + 10 d + 25 q = 30,000 cents 5 n + 20 n + 12.5 n = 30,000 37.5 n = 30,000 n = 800 so q = 400 D
July 14, 2016

MATH
You want the inverse of: y = (1/3)^x ????? hmmm maybe try x = (1/3)^y ln x = y ln(1/3) y = ln x /ln(1/3) = -ln x ln 3 y = - 1.1 ln x approximately
July 14, 2016

Chemistry
You are welcome namesake :)
July 14, 2016

Chemistry
thanks dude !
July 14, 2016

Chemistry
mols N2H4/ mols H2O2 = 1/2 mols N2H4/mols water = 1/4
July 14, 2016

Chemistry
N2H4 + 2H2O2= N2 + 4H2O What are the mole ratios of hydrazine (N2H4) to hydrogen peroxide (H2O2) and hydrazine to water
July 14, 2016

pre cal
u dot v = revenue which is sum of number of each times price of each so 1.05 ( u dot v )
July 14, 2016

physics
1 km * 1000 m/km * 1 s/4 m * 1 min/60 s = 250/60 = 25/6 minutes
July 9, 2016

physics
factors: 1609 m/mi 3600 s/h 1000 m/km 24 hr/d ======================= (.9mi/.5h) = 1.8 mi/h =========================== now (1.8mi/h)(1609m/mi)(1h/3600s) = (1.8*1609/3600) m/s ==================== (1.8*1609/3600)m/s (1km/1000m)(3600*24 s/d) = 1.8*1.609*24 km/d
July 9, 2016

physics
70 mi/h *1 h/60 min = (7/6)mi/min (7/6)(mi/min)(24 min) = 7*4 mi = 28 miles
July 9, 2016

Math (money)
c > 17+ 8 or c > 25
July 9, 2016

Math
pi radians = 180 degrees so 47.1 deg (pi rad/180 deg) = 0.822 radians
July 9, 2016

Mathematics
3 pi/9 + pi/9 or pi/3 + pi/9 180/3 + 180/9 60 + 20 80 or simply (4/9)(180) = 80
July 9, 2016

no - supplement
pi not 2 pi 13 pi/13 - 11 pi/13 = 2 pi/13 so d
July 9, 2016

Calculus
well, any old plane that is not parallel to the other two will intersect both at a point along the lines of intersection of those planes. The line of intersection will be parallel to the cross product of or two normals i j k 1 1 3 1-1 2 Find a plane that has that line of ...
July 8, 2016

Got to be kidding
Due to bending in a beam? Due to weight of mass hanging from ceiling by string? Due to compression sound wave in steel bar? Due to cooling of same bar while ends are fixed? etc etc etc etc ........
July 7, 2016

Physics
force = m g = 8 (9.81) work = potential energy gained = m g h = 8 (9.81)(12) power = work/time = 8 (9.81)(12)/15 If for some incomprehensible reason you really ant power/force, divide 12/15
July 7, 2016

Maths
amount = original * (1+r)^t 3 = (1+r)^t ln 3 = t ln (1+r) t = ln 3 / ln(1+r) r = .09 t = ln 3 / ln(1.09) t = 1.0986 / .086178 t = 12.74 years ====================== check 3 = 1 * 1.09^12.74 ?????? 3 = 2.997 yes that will do
July 7, 2016

Physics
u = horizontal speed = 73/3 = 24.3 m/s falls 8 meters in 3 seconds h = Hi + Vi t - 4.9 t^2 0 = 8 + 3 Vi - 9(4.9) Vi = 12 m/s upward speed at tree top of 8 m so let's find the top above that tree v = Vi -9.81 t 0 = 12 - 9.81 t t = 1.22 seconds rising above tree so h at top ...
July 5, 2016

Physics
find ke before child jumps (1/2)I omega^2 find new I (which you did already) find new omega (which you did already) Find new ke = (1/2) Inew (omega new)^2 now work done = new ke - old ke I went up a little but omega went down so I suspect the work will be negative In other ...
July 5, 2016

been there, done that
http://www.jiskha.com/display.cgi?id=1467694862
July 5, 2016

Physics
p = m v Ke = (1/2) m v^2
July 5, 2016

Physics
Force * time = change of momentum T (7*10^-4) = 2 * 6
July 5, 2016

Physics
impulse = change of momentum = force * time
July 5, 2016

Physics
Power * time = change in energy 20 P = m g h = 1800 * 9.81 * 15
July 5, 2016

Physics
(1/2) m v^2 = m g (45-5) v^2 = 2 (9.81)(40) --------------------------------- Second question has no real answer unless we assume that the potential energy is zero at the ground level. ONLY changes in potential have meaning,and you must always define a base If we ASSUME U = 0 ...
July 5, 2016

Physics
Maybe assume they both take the same time to stop when they crash into you Force * time = change in momentum for duck Force * time = 2.8 * .35 for goose Force * time = 3.4 * .75
July 5, 2016

Prealgebra/probability
tails, tails, heads does NOT work H H T H T H T H H Quarter, Penny could be H H H T T H T T that is four, 8 now for each so 32 so I agree
July 3, 2016

physics
add up the forces. That is one equation add up the torques (moments) about x = 0. That is the second equation
July 3, 2016

physics
C + W = 926 so 2 W = 1852 - 2 C then (1852 - 2 C) + .6 C = 736 1852 - 736 = 1.4 C etc
July 3, 2016

physics
190 down at left C up at x = .6 75*9.81 down at x = 1 W up at x = 2 forces up = forces down C + W = 190 + 75*9.81 = 926 Newtons moments about x = 0 sum to 0 -.6 C + 75*9.81*1 - 2 W = 0 or 2W +.6C = 736 Newton meters
July 3, 2016

Physics
lol, finally 33 * 50 = 12 x x = 33 * 50/12
July 3, 2016

Physics
so where is the fulcrum?
July 3, 2016

LOL - not enough known
I do not know either mass or the x of the right hand side
July 3, 2016

Physics
v = Vi + a t 0 = 30 + a (6) a = -5 m/s^2 ==================== v = Vi - 5 t 0 = 40 - 5 t t = 8 seconds
July 3, 2016

physics
work = force * distance so how far? assume v =0 at start F = m a 4 = 20 a a = (1/5) m/s^2 v = Vi + a t v = 0 + 3 a x = Xi + Vi t + (1/2) a t^2 x = 0 + 0 + (1/2)(9) x = 4.5 meters so W = F x = 4 * 4.5 = 18 Joules
July 3, 2016

math
2 (L+w) = 270 L + .75 L = 135 1.75 L = 135 L = 135/1.75 etc
July 3, 2016

math
a + 3 a = 80 so 4 a = 80 a = 20 etc
July 3, 2016

Math
b = (5/8) s so g = (3/8) s now g = (3/8) s + 6 and number of students = s + 6 b = 5/8 s = (3/8)s +6 so (2/8)s = 6 s = 24 that was original s s+6 = new total = 30
July 3, 2016

better
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/atomic/covalentrev4.shtml
July 3, 2016

CHEMISTRY
http://search.yahoo.com/yhs/search?p=dot+and+cross+diagram+H2O+bond&ei=UTF-8&hspart=mozilla&hsimp=yhs-001
July 3, 2016

Physics
find resultant and do the opposite. north 11 + 22 sin 30 east 22 cos 30 magnitude = sqrt(north^2 + east^2) tan angle north of east = north/east you want that magnitude but opposite direction, same angle south of west
July 2, 2016

PHYSICS
vol = 20 cm^3 ????? Your typing is very confusing then upward force = weight of water displaced (Archimedes) = 10 cm^3 * 1 gram/cm3 * g = 10 grams * g = .010 kg * 9.81 = .098 Newtons upward buoyancy but weight = volume * density * g = 20 * 2.5 * 9.81/1000 = 0.49 N difference...
July 2, 2016

Math
no if she made 65 out of 100 that will take less than if she made 650 out of 1000
July 2, 2016

Physics
(1/2) m v2^2 = 1.23 (1/2) m v1^2 so v2 = sqrt(1.23) v1 v2 = 1.11 v1 well, that is an 11% increase
July 2, 2016

Mathematics
25 letters allowed for first spot 25 for second spot so 625 letter combinations 9 digits 9*9*9*9 = 9^4 so 625*9^4 = 4,100,625
July 2, 2016

physics
or to do it the physics way: (4585 drops/ft^2)*(1 ft^2/15 tiles) = (4585 drops/ 15 tiles)
July 2, 2016

physics
4585/15
July 2, 2016

patel
must be bigger than 1 because 1^2 = 1 must be smaller than 2 because 2^2 = 4 so between 1 and 2 by the way sqrt 3 = 1.732050808 approximately
July 2, 2016

Sciencr
Yes, hot air holds more water. Fog happens if air saturated with all the moisture it can hold cools down. Similarly if saturated air comes in contact with a cool surface like a basement wall that air cools and the water condenses out. Interestingly by the way, hot water holds ...
July 2, 2016

physics
Are you sure the captain is a novice? Despite the fact that he will land downstream from his starting point, his fastest path across the water is to head straight across. Anyway I will pretend I am not a navigator and do what your book wants you to do. For example: He could be...
July 2, 2016

gibberish
please check what you wrote "Earth is 2R times far away from earth " makes no sense to me.
July 2, 2016

physics
force 1215 m what is that about? Anyway all that matters is depth p = rho g h = 1000 kg/m^3 * 9.81 * 3 = about 30,000 Pascals that is the pressure abouve the one atmosphere at the surface or "gage" pressure. That one atmosphere is about 100,000 Pascals so the total ...
July 2, 2016

Math(Assignment Due
http://davidmlane.com/hyperstat/z_table.html
June 29, 2016

Math(Assignment Due
Google David Lane normal distribution
June 29, 2016

Math
6*5*4*3= 30*12 = 360
June 29, 2016

Math1
165 * 1.04
June 28, 2016

Calculus
x^2 dy+2xydx - 2ydy +(1/xy)(xdy+ydx) = 0 [x^2-2y+1/y]dy + [2xy+1/x]dx = 0 dy/dx = -[2xy+1/x] / [x^2-2y+1/y]
June 28, 2016

Math
small left ---> large right 5467
June 28, 2016

Probability and statistic
http://davidmlane.com/hyperstat/z_table.html
June 27, 2016

physics
60,000 /3600 = 16.7 m/s 45,000 /3600 = 12.5 m/s v =Vi + a t 12.5 = 16.7 + 10 a a = -0.42 meters/second^2
June 27, 2016

physics
d = (1/2) a t^2
June 27, 2016

Math
in the slope/intercept form: y = m x + b m is the slope b is the y axis intercept where x = 0 here the slope is positive 0.5 so the line goes up to the right from the point (0,-2) (and of course down to the left :)
June 27, 2016

Math
y = 35 + 15 x
June 27, 2016

maths
(x-3)(3x+2)=0 alpha = 3 beta = -2/3 so (x-9)(x-4/9) = y x^2 -9x -4x/9 + 4 = y y = x^2 - (85/9) x + 4
June 27, 2016

English
One says "at". I suppose if you live in a tunnel, you eat "in" it :) However is you say: "What about dinner in my house?", You probably mean instead of in my yard or garage.
June 26, 2016

GEOMETRY
p(a)+ p (b) - p(a and b) 1,2,3,or 4 out of 6 = 4/6 tail = 1/2 = 3/6 4/6 + 3/6 - 2/6 = 5/6
June 26, 2016

GEOMETRY
prob of first one blue = 5/16 now we have 15 in the bag prob of white = 5/15 = 1/3 so 5/16 * 1/3 = 5/39
June 26, 2016

GEOMETRY
Hey, it is time you should be able to do these.
June 26, 2016

GEOMETRY
A and B could be 6 A and C - impossible B and C - impossible
June 26, 2016

GEOMETRY
the attempts are independent so (3/7)^3
June 26, 2016

GEOMETRY
2 out of 15 2/15
June 26, 2016

GEOMETRY
1/16
June 26, 2016

math
18,000 * 1.07^18
June 26, 2016

GEOMETRY
p even = 3/6 = 1/2 p A = 1/3 they are independent so 1/2 * 1/3 = 1/6
June 26, 2016

Math
cos T * sin T = 1/4 so 2 cos T * sin T = 1/2 so sin 2 T = 1/2 thus 2 T = 30 deg or pi/6 radians T = pi/12 radians or 15 deg now cos * sin must be + so T in quadrant 1 or quadrant 3 so actually T = pi/12 or T = 13pi/12 which is 195 deg pi/12 + 13 pi/12 + (2pi+pi/12) = (1/12 +13...
June 26, 2016

Biology
http://shenndesigns.weebly.com/my-physical-trait---curly-hair.html half of each assuming no one has only a little curly so 4:4
June 26, 2016

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