Thursday
July 28, 2016

Posts by Damon

Total # Posts: 26,563

world history
First of all, who says? Although the habit is to treat Chinese dynasties as succeeding, there is no reason they should not have overlapped. That said, they had, as the Chinese always had, nomadic tribes to the north and west and the bleak ocean to the east. Mostly mountains ...
July 27, 2016

science(physics)
momentum = 0.100 * 20 = 2 kg m/s distance into plank = .020 meter average speed in plank = 20/2 = 10 m/s time in plank = .020/10 = .002 s average force = change in momentum/time = 2/.002 = 1000 Newtons
July 27, 2016

math
(9/36)*900 = 900/4 = 225
July 26, 2016

Math
This is not a submarine but a research submersible. Submarines do not go much deeper than a couple of boat lengths. 8 * 60 + 37 = 517 seconds 517 seconds * 25 ft/s = 12,925 feet Although that is far deeper than a submarine dives, it is less than half as deep as the Mariana ...
July 26, 2016

Chemistry
How much H3PO4 is needed to neutralize 1 liter of a 0.75M solution of NaOH? (in moles)
July 26, 2016

Math
8 sin 30 + 8 sin 120 8 (1/2) + 8 (1/2) sqrt 3
July 26, 2016

math
must be combined age? p = 2 j p-17 + j-17 = 33 p + j = 67 2 j + j = 67 3 j = 67 j = 67/3 = 22 1/3 so p = 134/3 = 44 2/3
July 26, 2016

physics
h = Hi + Vi t - 4.9 t^2 v = Vi - 9.81 t when is v = 0 ? (the top) t = 30/9.81 = 3.06 seconds coasting up to a stop so h = 50 + 30 (3.06) - 4.9 (3.06)^2
July 26, 2016

Physics
You kidding? 200 - 3(45)
July 26, 2016

physics
v = Vi - 9.81 t h = Hi + Vi t - 4.9 t^2 42 = 0 + Vi(2) - 4.9(4) Vi = 30.8 meters/ second when it hits ground, v = -30.8 m/s v = Vi - 9.81 t -30.8 = 30.8 - 9.81 t t = 6.28 seconds
July 25, 2016

Chemistry
Thank you so much!
July 25, 2016

Chemistry
What volume of nitrogen dioxide (in L) is produced from the complete reaction of 16.87 of lead (ii) nitrate at STP
July 25, 2016

college physics
time for one wave = period = 1/f = 10/30 so f = 3 Hz
July 25, 2016

physics
u = 10 m/s forever v = -gt = -9.81 (3) = - 29.4 m/s check if it hit the ground d = (1/2) g t^2 = 4.9 * 9 = 44.1 so still in the air speed = sqrt (10^2 + 29.4^2)
July 25, 2016

Maths
a + 20 = 3 (180-a) a + 20 = 540 - 3 a 4 a = 520 a = 130 180-a = 50
July 25, 2016

Maths
(n + m)/2 = 15 so n + m = 30 m = (30-n) (n m )^.5= 9 n m = 81 n(30-n) = 81 -n^2 + 30 n = 81 n^2 -30 + 81 = 0 (n-3)(n-27) = 0 3 and 27
July 25, 2016

General Mathematics
http://www.jiskha.com/display.cgi?id=1469428320
July 25, 2016

Maths
7 +8 +3 = 18 so 2 are white 2/20 = 0.1
July 25, 2016

huh? typos?
maybe 2 meters deep and find volume not height? if so v = w L d = 20 *100 *2 = 4,000 m^3
July 25, 2016

Math (Rational Inequality)
x^2 h = 8 x = sqrt(8/h) if h = x x = h = 2 if x > h, not allowed if x < h then h > 2 so x < 2
July 25, 2016

algebra
Well, you know 48 = 16*3 You know that 3/3 = 1 so multiply 3/16 by 3/3 and get 9/48
July 25, 2016

ststistics
binomial distribution p = .24 1-p = .76 n = 10 P(2) = C(10,2).24^2 (.76^8) but C(10,2) = 45 so 45 * .0576 * .111 = .288 P(1) = 10 * .24 * .76^9 = .203 so answer to b is 1 - .288 - .203 c is same way but boring. you do it
July 25, 2016

Hey wait a minute
This is very, very similar to one I already helped you with. Please try them yourself. It does not do you any good to have us do all the problems for you. The idea is that we can help, but not do virtually the same problem over and over for you. http://www.jiskha.com/display....
July 24, 2016

MATH
let x = tan t then dx = sec^2 t dt sec^2 t dt/[ tan t (1+tan^2 t) ] NOTE: 1+tan^2 t = sec^2 t !!! wow that helps :) so we have dt/tan t = ctn t dt = ln (sin u)
July 24, 2016

Math
u = 1 - y^2 du = -2 y dy or dy = du/-2y ((y^3)/(u^2))[du/-2y] (-1/2)y^2 du/u^2 but y^2 = 1-u so -(1/2)(1-u) du/u^2 = (u/2)du/u^2 - (1/2)du/u^2 = (1/2) du/u - .5 u^-2 du finish and check my arithmetic :)
July 24, 2016

Someone Please Help me- PreCalc
x^2 + y^2 = 1 16/49 + y^2 = 49/49 y^2 = 33/49 y = +/- sqrt (33) /7 so since in Q IV where y is negative (4/7, -sqrt(33)/7 )
July 24, 2016

physics
10 * 100
July 24, 2016

physics
potential energy at top = kinetic energy at bottom m g h = (1/2) m v^2
July 24, 2016

maths
24 + 5 - 17
July 24, 2016

Physics
Oh, do cos wt = -1/2 as well
July 24, 2016

Physics
x = X sin w t v = X w cos w t so X w cos w t = (1/2) X w cos w t = 1/2 w t = 60 degrees, 300 degrees etc or in radians pi/3 etc so what is x/X when wt = pi/3 etc x/X = sin wt x/X = sin 60, 300 etc x/X = .866 , -.866 etc
July 24, 2016

Math
x + 24 = 36 ?? -24 = -24 ---------------add x + 0 = 12 so x = 12
July 23, 2016

Math
.3(10) = 3 .3(10+10) = 3+3 = 6 .3(10+10+10) = 3+3+3= 9
July 23, 2016

physic
kinetic energy = (1/2) m v^2 that goes into heating the brakes (use Joules not calories) energy =specific heat*mass*(Tend-Tbegin)
July 23, 2016

Science
(1/2) m v^2 = (1/2)(1/2)(9) = 9/4 Joules
July 22, 2016

math
first blue: 6/16 second blue 5/15 so 3/8 * 1/3 = 1/8 = 0.125
July 22, 2016

math whoops 4/13
sorry, 4/13
July 22, 2016

math
careful !
July 22, 2016

math 11/36
http://davidmlane.com/hyperstat/A136602.html
July 22, 2016

math
Yes,note unlike the other two questions because red and spade are mutually exclusive
July 22, 2016

physicis
metal A length x metal B length (15-x) x(4.3)(pi r^2) + (15-x)(6.3)(pi r^2) = 21757 4.3 x + 94.3 - 6.3 x = 21757/(81 pi) 2 x = 8.8 x = 4.4 cm
July 22, 2016

Physics
m = 670/g = 670/9.81 = 68.3 kg F = G m Ms/(r^2) F=6.67*10^-11*68.3*1.99*10^30/7500^2
July 22, 2016

stats
http://davidmlane.com/hyperstat/z_table.html
July 22, 2016

PHYSICS
well, I am just going to estimate iron density about 8 times water 8000 kg/m^3 or 8 g/cm^3 8 L pi r^2 = 8(85)(3)(2.5)^2 about 8 * 85 *3 * 6.3 or 12852 grams 12.8 kg no problem :) less than 30 pounds
July 22, 2016

maths
n cupcskes n/6 to neighbor , 5n/6 remain (7/10)(5n/6) to sister or 7n/12 to sister (3/10)(5n/6) remain or n/4 remain so n/4 =12 n =48
July 22, 2016

Physics
How high does it go? v = Vi -9.81 t at top v = 0 0 = 14 -9.81 t so t = 14/9.81 then h = 100 + 14 t - 4.9 t^2 now fall from h v^2 = 2 g h
July 22, 2016

Algebra
x and (60-x) 2 x -.5(60-x) = 10 2 x -30 +.5 x = 10 2.5 x = 40 25 x =400 x = 16 60-x = 44
July 22, 2016

Algebra
(y-a)^2 = y^2 - 7 y + p y^2 - 2 a + a^2 = y^2 - 7 y + p 2 a = 7 a = 7/2 so p = a^2 = 49/4
July 22, 2016

Physics,Mthe
mass/volume = density =100/10 = 10 but you have given no units so it could be anything at all.
July 22, 2016

math
96
July 21, 2016

math
64
July 21, 2016

math
32
July 21, 2016

Physics
I am not going to just give you the answers to these very basic questions. Try yourself and maybe someone will help if you get messed up.
July 21, 2016

No way !
No, I refuse to just answer. You say and tell us why. What do you think? What is the difference between mass and weight? Would it be different at different locations in the body?
July 21, 2016

American History
Budgets cuts in our Defense has led to inefficient weapons available to the soldiers to fight wars here in America or Overseas. ??????????????????? Please compare US defense budgets and resulting weaponry to those of other countries.
July 21, 2016

Math
For what value(s) of r is r^2+5r+6/r+2 equal to 0? A) -2 only B) -3 only C) 3 only D)-2 or -3 E) 2 or 3 I got A but it is incorrect and I'm still confused Thanks
July 20, 2016

Chemistry
How many grams of hydrogen peroxide (H2O2) must be added to 1,500 ml of water to produce a concentration of 1.33 m (molal solution)?
July 20, 2016

Math
checks at http://www.mortgagecalculator.org/
July 20, 2016

Math
payment = principal [ r/ (1 - {1+r}^-n) ] here principal = 200,000 r = .10/12 = .0083333333..... n = 25*12 = 300 = 200,000 [ .00833... / (1-{1.00833..}^-300) ] = 200,000 [ .009087 ] = 1817.40
July 20, 2016

math
7 * 9 = 63 315/63 = 5 so 7 * 9 * 5 = 315
July 20, 2016

Geometry
y = 2 x - 5 to y = 2 x moves up 5
July 20, 2016

Math
have played x have won .75 x will have won .75 x + 4 will have played x + 4 so .75 x + 4 = .80 (x +4) 4 - .8*4 = .05 x 4 - 3.2 = .05 x .8 = .05 x 800 = 5 x x = 160
July 20, 2016

Algebra
c^2 + 18 c - 175 = 0 (c + 25)(c - 7) = 0 c = 7 or c = -25
July 20, 2016

statistics
15951/13 = 1227 per yesr
July 20, 2016

Math
7 1/2 = 15/2 15/2 / 3/4 = 30/3 = 10 =============== or 10 * 3/4 = 30/4 = 7 1/2
July 20, 2016

algebra
Well, if the denominator is constant and x is alone up there (no x^2 or sin x or anything) then yes
July 19, 2016

Northwest is not 30 deg n of e
when you get the geometry figured out look at: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/forwir2.html
July 19, 2016

Nobody knows
we do not know what the dimensions were on the plans, or alternately the area. If you know the area on the plan, A in^2 then Areal = A (9 ft^2/6.25 in^2)
July 19, 2016

physics
Well, you could use Maxwell's equations, but it might be easier to make a common sense guess. If moving the magnet makes a voltage, then it is likely that moving it faster will make a bigger voltage.
July 19, 2016

Physics
ps: That is what potential is all about.
July 19, 2016

Physics
exactly as much as to slide down one mountain and up the one beside it to the same height, with no friction of course.
July 19, 2016

Math
71/163 = F/756 so F = 756 * 71 / 163
July 17, 2016

Maths
21 - 13 = 8 play only C 16 - 13 = 3 play only F 8+3+13 = 24
July 17, 2016

University of jos,physics
ROFL zero, went nowhere Now average speed is another matter.
July 17, 2016

Math
I think it is just folded three times so the short edges can be welded together. No top and bottom yet
July 17, 2016

Math
height = 20 side length = 36/4 = 9 volume = 9*9*20 cm^3 top = 81 cm^2 bottom = 81 cm^2 81 * 2 = 162 cm^2
July 17, 2016

University of jos,physics
distance = sqrt (3^2 + 4^2) = 5 sin angle north of east = 3/5 = 0.6
July 17, 2016

University of jos,physics
h = (1/2) g t^2 if g = 9.81 h = 4.9 (25)
July 17, 2016

Physics
The link tells you right off. 2.25*10^8 instead of 3*10^8
July 17, 2016

Physics
http://www.google.com/search?q=velocity+of+light+in+water&ie=utf-8&oe=utf-8
July 17, 2016

Physics
What are you using for c? The velocity of light in water is lower than in a vacuum, which you know I am sure from your experience trying to shoot fish with a bow and arrow. If you are using about 3*10^8 m/s, that is wrong.
July 17, 2016

typo ?
"perimeter 10 meters " I guess maybe you mean ten times but it is still nonsense 1000 = 25 L so L = 40 m 1000 = 10 ( L+w) 100 = 40 + w so w = 60 area = L * w obviously there is something wrong. width bigger than length
July 17, 2016

math
5 maybe ?
July 17, 2016

pre cal
well g = x^2 + anything will work. Steve used zero
July 17, 2016

pre cal
where are the zeros of this parabola? x^2 + 6 x + 18 = 0 x = [-6 +/- sqrt (36-72)]/2 = -3 +/- 3 vertex is at x = -3 g has it at at x = 0 how high is it? roots are not real so above x axis y = (-3)^2 -18 +18 = 9 so to be even g(x) = x^2 + k when x = 0, y must be 9 so g(x) = x^2...
July 17, 2016

math
7!/[ 3! * 4! ] 7 * 6 * 5 / 3*2 35 all right
July 17, 2016

Math
total approach speed = 127 km/h 635 / 127 = 5 hours
July 17, 2016

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

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