Wednesday
September 2, 2015

Posts by Damon


Total # Posts: 21,878

physics
i = Q/t or amps = coulombs/second you do not need the electron charge for this - red herring intended to confuse you.
April 24, 2015

DISCRETE MATH
p fail = .2 p pass = .8 p five pass = .8^5 = .32768
April 24, 2015

physics
n * electron chsrge = 3.2*10^-6 Coulombs
April 24, 2015

AP CALC
d^2f/dx^2 <0 in other words curves down, sheds water
April 24, 2015

Math
6 sprinters 3 at a time but ORDER matters so we are talking permutations not combinations n!/(n-r)! = 6!/3! = 6*5*4 = 120
April 23, 2015

Chemistry
6.02*10^23 molecules/mol so 40.79kJ /6.02*10^23 molecules times I suspect you mean 8.51*10^10 molecules 40.79 (8.51/6.02)10^(10-23) 57.66 * 10^-13 or 5.766 * 10^-12 kJ
April 23, 2015

no idea
I have no idea what our experiment is.
April 23, 2015

Algebra
when y = 0 , x = 6 0 = 6m + b b = -6m so for the second one y = 3mx -6m when y = 0 6 m = 3 m x x = 2
April 23, 2015

Math Help
26 letters - 2 = 24 letters choice of 24 letters for first letter since letters can be repeated we have 24*24 = 576 letter combinations now we have ten numbers, 0 through 9 again they can be repeated (AA0000 is allowed) 10^4 = 10,000 so 576 * 10,000 = 5.76 * 1,000,000 = 5,760,000
April 23, 2015

Math
2^15 32768
April 23, 2015

Math 222
-x^2 + 3 x + 5 = 0 x^2 - 3 x - 5 = 0 x = [ +3 +/- sqrt(9 + 20) ] / 2 1.5 +/- 2.69
April 23, 2015

Math 222
a^2 - 6 a + 9 = 0 (a-3)(a-3) = 0 a = 3 or a = 3, in other words the vertex is on the x axis.
April 23, 2015

Math 222
a^(1/3) a^(3/2) a^(-1/2) a^ [ 1/3 + 3/2 -1/2 ] a^[1 1/3] or a^(4/3)
April 23, 2015

Geometry
V = k x^3 A = c x^2 for big one xb^3 = 1331/k for small one xs^3 = 216/k or xb/xs = (1331/216)^(1/3)= 1.83333333.... so xb^2/xs^2 = area ratio = 3.361111.... 484/3.361111... = 144
April 23, 2015

World History
alliances
April 23, 2015

SOCIAL STDIES HELP!
We checked all three.
April 23, 2015

SOCIAL STDIES HELP!
1. agree - roaring 20s until Oct 1929 2. NOT TV - happened when I was in elementary school LOL Electricity yes. stuff like washing machines was mostly after WW2. I remember rollers turned by hand to squeeze water out of laundry from tub. I suppose you could count that in which...
April 23, 2015

Math 222
eighth root of a^7
April 23, 2015

Math 222
sqrt 50 or sqrt(50 x^3) ?????? I will assume sqrt (50 x^3) 4 u sqrt(2*25) x sqrtx - x sqrt(2*16) sqrtx * u 20 u x sqrt(2x) - 4 u x sqrt(2x) 16 u x sqrt(2x)
April 23, 2015

Physics
first use conservation of momentum to get swing speed at bottom Vswing = Vbird (Mass bird/Mass swing) then m g h = (1/2) m Vswing^2 or h = Vswing^2/(2 *9.81)
April 23, 2015

Math
each term is half the previous one 1.6 *.5^(n-1) is a geometric sequence
April 23, 2015

Precalculus
in other words y = 4(n-1) = 4x - 4
April 23, 2015

Precalculus
(n+1,4n) from n = 0 to n --->oo seems to work
April 23, 2015

chemistry
NaNO3 = 23 + 14 + 3(16) = 85 g/mol 2.528/85 = .03 mol *1000 mL/.503mol = 59.1 mL
April 22, 2015

chemistry
.516 * 111.5/1000
April 22, 2015

precalculus
y^2 - 2 y = -x You were asked to eliminate the parameter t, not to solve for y. However I do not know the traditions of your particular group :)
April 22, 2015

precalculus
t^2 = 1-x t = y-1 so t^2 = y^2-2y+1 so y^2-2y+1 = 1 - x
April 22, 2015

math
http://www.jiskha.com/display.cgi?id=1429755553
April 22, 2015

Math
Draw it !!!!! call missing point P slope XY = (-2-6)/(5+1) = -8/6 =-4/3 so for XY y = -(4/3) x + something BUT WP has same slope y = -(4/3) x + b 3 = -(4/3) (-5) + b b = 3 - 20/3 = -11/3 3 y = -4x - 11 is WP Find YP the same way it is parallel to XW then find intersection of ...
April 22, 2015

Math
25*15 = 375 ft^2 1 yd = 9 ft^2 so 375/9 = 41 2/3 yd^2 41 2/3 * 20 = $833.33 no way , use cheaper carpet and install it yourself !
April 22, 2015

math
On a three day hike, Robert hiked twice as many miles on the first day as on the second day. On the third day he hiked 5 miles. Carlos hiked 5 miles on the first day and three times as many miles on the second day as on the third day. (a) Write and simplify an expression for ...
April 22, 2015

pre-calculus
t^2 = 1-x t = y-1 so t^2 = y^2-2y+1 so y^2-2y+1 = 1 - x
April 22, 2015

pre-calculus
hey, just pick some points note x^2+y^2 = r^2 = circle
April 22, 2015

pre-calculus
because I learned in a trig course the sin^2 x + cos^2 x = 1
April 22, 2015

pre-calculus
x = 1 + cos t y = 1 - sin t cos t = (x-1) sin t = (1-y) cos^2 t = (x-1)^2 sin^2 t = (1-y)^2 ----------------- add 1 = (x-1)^2 + (1-y)^2 your turn :)
April 22, 2015

Math
same slope (6-9) / (5+4) = (-1-y) / (-3-3)
April 22, 2015

math typo I think
I see Robert and Carlos but who is Matt?
April 22, 2015

Math
P is (0,T) slope of CD = 2/-3 = -2/3 slope of PC is then 3/2 so PC is y = (3/2)x + b at C, x = -3 and y = -6 -6 = 1.5 (-3) + b b = -6 + 4.5 = -1.5 so y = 1.5 x - 1.5 on the x axis when y = 0 x = 1 sp P at (1,0)
April 22, 2015

Math
2 = (0-12)/(a-4)
April 22, 2015

history of math
You are welcome.
April 22, 2015

history of math
s = 2 w w = 2 d so s = 4 d w = 2 d 4 d + 2 d + d = 100 7 d = 100 so d = 100/7 (not the wife) check if d = 100/7 w = 200/7 and s = 400/7
April 22, 2015

Problem solving
a + b = 7869 a - b = 1879 ------------ add 2 a = 9748 a = 4874 then b = 7869-4874 = 2995
April 22, 2015

algebra 2
s + a = 358 so s =358-a 1.5 s + 3.25 a =752.25 1.5(358-a) + 3.25 a = 752.25 find a then s
April 22, 2015

7th grade math
all correct 4. ratio of model to full scale is 1/25 1/25 = 3.8/h h = 25 * 3.8 = 95 yes
April 22, 2015

calculus
same as your fence really a + b = 40 so b = 40 - a P = a b = a(40-a) = 40 a - a^2 dP/da = 40 - 2 a a = 20 then b = 20 so 20 and 20
April 22, 2015

PHYSICS
well we agree on part a and part b is easy
April 22, 2015

PHYSICS
http://www.jiskha.com/display.cgi?id=1429748458
April 22, 2015

calculus
p + 2 q = 800 so p = 800 - 2 q A = p q = (800 - 2q)q A = -2 q^2 + 800 q now you could find the vertex of this parabola easily with Algebra 2 by completing the square but you said calculus so dA/dq = 0 at max = -4 q + 800 or q = 200 then p = 800 - 400 = 400 so A = 80,000 ft^2 ...
April 22, 2015

PHYSICS PLEASE HELP
http://www.jiskha.com/display.cgi?id=1429748458
April 22, 2015

PLEASE HELP
sorry, had to drop further to make up for friction m g h = -1902 -187 = -2089 Joules and h = 2089/(60.8*9.81)
April 22, 2015

PLEASE HELP
He must have been heading downhill ! change in kinetic energy = (1/2)(60.8)(8.12^2 - 1.84^2 ) = 1902 Joules energy in = -278 + 90.8 = -187.2 h = 0 initially m g h = - 1902 + 187 = - 1715 Joules h = -1715/(60.8*9.81) = - 2.88 meters so 2.88 is absolute value
April 22, 2015

Pre-Calculus
think 14 x^2/56y^3 = (14/56)(x^2/y^3)
April 22, 2015

Pre-Calculus
sure (2/4) of anything is (1/2) of anything
April 22, 2015

Pre-Calculus
14/56 = 1/4
April 22, 2015

math
integral ln x / x = (1/2)(ln x)^2 because d/dx (ln x)^2 = 2 ln x (1/x) you can do the rest
April 22, 2015

calculus
x is + over the interval so the function we want to integrate is always + over the interval when you see something squared on the bottom think: d/du (v/u) = [ u dv/du - v ] / u^2 so here let u = (3x+1) if v were 1 d/du(v/u) = [0-3]/(3x+1)^2 so let v = -1/3 and integral = -(1/3...
April 22, 2015

Physics
Moments about center of yoyo shaft torque = 2*(.5/100) = .01 NM omega = alpha * t but alpha = Torque/ I so omega =Torque * t/I or I = Torque * t / omega = .01 * 5 / 15 ========================= angle = (1/2) alpha t^2 ============================ now for part c I assume you no...
April 22, 2015

Math
a ton is 2000 pounds in English as opposed to metric or shipping units. I suspect you want the 2000 pound ton then 7 tons is 14,000 pounds so 14,000 / 40 = 1400/4 =?
April 22, 2015

Science
The wiki article is pretty good on this subject: http://en.wikipedia.org/wiki/Thermocouple
April 22, 2015

Math
you are looking for the least common multiple of 252 and 408 The way I do such problems is to factor each 252 = 2*126 = 2*2*63 = 2*2*3*21 = 2*2*3*3*7 then 408 = 2*204 = 2*2*102 = 2*2*2*51 so we need 2*2*2 * 3*3 * 7 * 51 = 8*9*7*51=25704 check 25704 / 252 = 102 blue 25704 / 408...
April 22, 2015

Math
(Y2-Y1) / (X2-X1) for example (-2-4)/(2 - -1) = -6/3
April 22, 2015

Chemistry
Dr Bob told you much more precisely than I how do do this sort of problem. I suggest just doing them. by the way, your book or Google will tell you how many grams of any element are in a mol. for example for H about 1 for O about 16 for C about 12 etc Do you not have a ...
April 22, 2015

If you answer these questions I will pass this cla
I assume all problems are at STP where a mol of gas is 22.4 Liters
April 22, 2015

If you answer these questions I will pass this cla
Hint, convert grams to mols
April 22, 2015

Trig
yes, about 1.3 radians
April 22, 2015

Trig
I assume you mean y = 7 cos θ + 24 sin θ well, my inclination is to look for where the derivative is 0 dy/dθ = -7 sin θ + 24 cos θ = 0 or tan θ = 24/7 = 3.43 θ = 73.7 degrees
April 22, 2015

AP Physics
Steve tried to answer earlier but you have still not given direction of velocity vector of the first ball. Anyway as he said conserve momentum in the north direction and in the east direction.
April 18, 2015

Physics
hmmm, that flat earth assumption again ! 60 = (1/2)(9.81) t^2
April 18, 2015

Vectors
x = -2 + 2 s y = 3 + 3 s z = 1 - s on the y axis, x and z are 0 0 = -2 +2 s 0 = 1 - s so it is where s = 1 then y = 3+3 = 6 so (0 , 6 , 0 )
April 18, 2015

Math - use flat earth
earth flat at this range :)
April 17, 2015

Vectors
Beats me Ryan
April 17, 2015

Vectors
find slope of perpendicular original is slope = -1 so slope of perpendicular is -1/-1 = 1 pick a point on line 2, like (0,0) then equation of perpendicular through that point is y = x (just to make it east) where does y = x hit the first line? 2 x + 2 x = 16 x = 4 then y = 4 ...
April 17, 2015

PRE - CALCULUS
I do not have time NOTE in your previous question, the determinant of the 3 by 3 coef matric is zero, can not solve.
April 17, 2015

DETERMINANT = 0
calculate the determinant of the 3 by 3 on the left as if you were going to do Cramer rule THE DETERMINANT IS ZERO
April 17, 2015

PRE - CALCULUS
Huh, they are 4 -1 3 12 1 4 6 -32 5 3 9 20 the trouble is that it can not be solved
April 17, 2015

PRE - CALCULUS
You mean this ? 17y+21z = -140 that would be 0 17 21 -140
April 17, 2015

PRE - CALCULUS
You can not reduce the last row to 0 0 1 something
April 17, 2015

PRE - CALCULUS
1 4 6 -32 yes but your problem gives a very strange answer
April 17, 2015

PRE - CALCULUS
http://www.idomaths.com/gauss_jordan.php
April 17, 2015

PRE - CALCULUS
4 -1 3 12 1 4 6 -32 5 3 9 20 Step 1: Swap row 3 and 1 5 3 9 20 1 4 6 -32 4 -1 3 12 Step 2: Divide row 1 by 5 1 0.6 1.8 4 1 4 6 -32 4 -1 3 12 Step 3: Subtract row 1 from row 2 1 0.6 1.8 4 0 3.4 4.2 -36 4 -1 3 12 Step 4: Subtract (4 × row 1) from row 3 1 0.6 1.8 4 0 3.4 4...
April 17, 2015

PRE - CALCULUS
I think they gave you Sk k(3k-1)/2 Sk+1 = Sk + 3 (k+1) - 2 = (3 k^2 - k)/2 + 3 k +1 = (1/2)( 3 k^2 - k + 6 k +2 ) = (1/2)(3 k^2 + 5k + 2) = 1.5 k^2 + 2.5 k + 1
April 17, 2015

chemistry
same as last one I just did
April 17, 2015

Chemistry
molar mass of Mg(OH)2 = 24.3+2*17 = 58.3 g so we have .605/58.3 = .0104 mol molar mass of H2SO4 = 2+32+64 = 98 g so we have 1/98 = .0102 mol so we will get .0102 mol of MgSO4 .0102 ( 24.3+32+64) = 1.23 g
April 17, 2015

PRE - CALCULUS
You are welcome.
April 17, 2015

PRE - CALCULUS
S1 = 1(4)/2 = 2 check S2 = 2+5 = 7 = ? 2(7)/2 = 7 check S3 = 7+8 = 15 = ? 3 (1+9) /2 = 3*5 = 15 check
April 17, 2015

Calculus
I do not know - ask teacher. Unless we made arithmetic errors, that should be right. Perhaps in terms of pi or something ?
April 17, 2015

Calculus
we had A = 15.5 D - .897 D^2 and we know D = 8.64 A = 15.5 (8.64) - .897(8.64^2) = 67 ft^2
April 17, 2015

Calculus
h is height of rectangle1 31 = 2 h + D + pi D/2 2 h = 31 -D(1+pi/2) h = 15.5 - (D/2) (1+pi/2) area = D h + (1/2)(pi D^2/4) A = D (15.5 -1.29 D) + (1/8)pi D^2 A = 15.5 D - .897 D^2 dA/dD = 0 at max = 15.5 - 1.79 D D = 8.64 ft then h = 4.4 ft check my arithmetic !
April 17, 2015

Math 222
assume your x means * or "times"? multiply --- add exponents raise to power - multiply exponents a^.25 b^.5 * a^1 b^.5 a^1.25 b^1 or a^(5/4) b
April 17, 2015

calc
first second a = change in V/change in t = 29.32/1 second second a = (50.82-29.32) /1
April 17, 2015

math
6!/(6-2)! = 6*5 = 30 yes 8!/ [ 5! (3!) ] = 8*7*6/(3*2) = 56 sure enough
April 17, 2015

math
26.19/2845 = .0092056 times 365/12 = .28 times 100 = 28 %
April 17, 2015

physics
r = mv/qB double r ---> double v
April 17, 2015

Vectors
I assume this is three dimensional y (3x+1) = 0 y = 0 is a plane and x = -1/3 is a plane
April 17, 2015

physics
So, what do you think?
April 17, 2015

math
2 L + 2 w = 29 L = 1 + 2 w so 2 + 4 w + w = 29 5 w = 27 I have a sneaking suspicion that you have a typo because the text writers always make this stuff come out whole numbers.
April 17, 2015

Physics
eyes to mirror bottom to sole of shoe. They do not ask about top of mirror and top of head :)
April 17, 2015

physics
-9.81 m/s^2 0 = 20 - 9.81 t then h = 20 t - 4.9 t^2 or (1/2) m v^2 = m g h so h = v^2/2g
April 17, 2015

physics
m g
April 17, 2015

physics
m (v^2/r - 9.81)
April 17, 2015

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