Monday
December 5, 2016

Posts by Damon

Total # Posts: 28,273

math
1. yes 2. yes, works for any old y 3. just like 2 4. yes
November 28, 2016

PHYS-041-Keiler: Physical Science
assuming 5730 year half life a = Ai e^-kt a/Ai = .5 = e^-k(5730) ln .5 = -k(5730) k = 1.21 *10^-4 so a = 22 e^-(1.21*10^-4*11400) = 22 * e^-1.38 = 22* .252 = 5.54 kg
November 27, 2016

physics
T = 2 pi sqrt(L/g)= (2 pi/sqrt g)L^.5 = 1 second at 22 deg so you can get initial L dT/dL = (2 pi/sqrt g).5 /sqrt L dT/dt = dT/dL * dL/dt so what is dL/dt dL/L = 24*10^-6 dT dL /dT = 24*10^-6 L dL/dt = dL/dT *dT/dt = 24*10^-6 (-.625) L so dT/dt = [(2 pi/sqrt g).5 /sqrt L][24*...
November 27, 2016

Physics
assume I = (1/2) m r^2 for disk = (1/2)(6.5)(r)^2 Torque = I alpha where alpha = ang acceleration = a/r T = tension in rope so torque = T * r = I (a/r) T = I a/r^2 = (.5 m )a=.5(6.5)a now the block force down = m g force up = T ma = mg - T T = mg-ma = 2.5(g-a) so putting them ...
November 27, 2016

Stoichiometry
4.5 grams, look below at earlier question
November 27, 2016

Math
12 marbles to start drew one yellow 4/12 then 11 marbles of which 3 are yellow 3/11 so 4/12 * 3/11 = 1/11
November 27, 2016

maths
cost = 1040 - 240 = 800 (240/800)100 = 30% profit 12 * 6.50
November 27, 2016

Stoichiometry
(75/1000).6 = .045 mol CaCO3 = 100 g/mol so 4.5 grams
November 27, 2016

Stoichiometry
CaCl2 + Na2CO3 ---> CaCO3 +2NaCl one to one in mols of each 75 *.6 = x * .4
November 27, 2016

maths
2400 * .15 2400 * 1.15 .8*2400 before VAT
November 27, 2016

maths
0.8 Liters * n = 36 Liters n = 38/0.8 = 45 cans ======================= b makes no sense to me. It is a typo I think.
November 27, 2016

Math
t/5 = (t-5)10 t = (t-5)50 t = 50 t -250 49 t =250 t = 250/49
November 27, 2016

Probablility
I assume you never use the same machine twice first cardio = 4/10 = 2/5 second = 3/9 =1/3 third = 2/8 = 1/4 fourth = 1/7 product = 2/5 *1/3*1/4*1/7 = 1/210 now weight first =6/10 = 3/5 second = 5/9 third = 4/8 = 1/2 fourth = 3/7 product = 3/5 * 5/9 * 1/2 * 3/7 =1/14 so 1/210...
November 27, 2016

Algebra
7-5.375 = 1.625 for left and right margins 1.625 - .3125 = 1.3125 for right margin do the vertical problem the same way
November 27, 2016

Algebra
75*20 + 95*30 = x * 50
November 27, 2016

Math
5 * 3/1 = 15
November 26, 2016

pre calculus
100(-.5 -.866i) - 50 - 50 sqrt3 i
November 26, 2016

pre calculus
we want r(cos T + i sin T) r = sqrt ((-2)^2 +2^2) =sqrt 8 =2 sqrt2 -2 = r cos T = 2 sqrt 2 cos T cos T =-sqrt 2 / 2 T = 3 pi/4 2 = R sin T = 2 sqrt 2 sin T sin T = sqrt2 /2 T = 3 pi/4 all right so z =2 sqrt 2[cos .75 pi+isin .75 pi]
November 26, 2016

AP Calculus
well lets think it might be like a hot stone cooling down to some room temperature Tf Google Newton's law of cooling T = Ts +(To-Ts)e^-(k t) To is your original 1900 time Ts is your final time in 2100 or whatever which is the fastest one can ever go k is a constant that ...
November 26, 2016

physics
Your second method is the right way to go.
November 26, 2016

pre calculus
I think you probably mean: e^(a+bi) =e^a e^bi = e^a (cosb+isinb) then e^i? = e^(0+i?) =(e^0)(cos pi+isinpi) = 1(-1 + 0) or e^i? = -1
November 26, 2016

7th grade Pre- Algebra
R/5 - 6 = -1 add 6 to both sides R/5 +0 = 6 - 1 R/5 = 5 now multiply both sides by 5 (R/5)5 = (5)(5) R = 25
November 26, 2016

missing question
[f(x)-f(a)] /(x-a) = 7 as x-->a is the definition of the derivative f'(a) = 7
November 26, 2016

math
df/dx = 4 x^2/[x^3 +3] at x = -1 df/dx = 4/[2] = 2 so f(-1+dx) = f(-1) + 2 dx here dx = -.1 so f(-1-.1) = -3 +2(-.1) = -3 -.2 =-3.2
November 26, 2016

Physics
t is in seconds 40 t = 42(t-120)
November 26, 2016

math
sin ? = 0 slope = cos ? = -1 f(x) = sin(?) -1(x-?) = -(x-?)
November 26, 2016

science
global positioning systemhttp://www.safewise.com/blog/10-wearable-safety-gps-devices-kids/ ( of course I use GPS to get around the bleak ocean but that is old stuff:) sampling whale snot with drone http://shop.whale.org/pages/snotbot tidal power generation systems http://...
November 26, 2016

Electronics
http://www.electronics-tutorials.ws/rc/rc_1.html
November 25, 2016

Math
s^3 = 512 s = 512^(1/3) calculate s = 8 A = 6 (s^2) = 6 * 64
November 25, 2016

Calculus application of sin function
v = dh/dt = sin pi t then h = - (1/pi)cos pi t but h = A cos (2 pi t/T) so A = -1/pi pi = 2 pi /T so T = 2 so in the ean h =-(1/pi) cos pit = -(1/pi)cos(2 pi t/2) B) h =-(1/pi) cos pit v = dh/dt = sin pi t a = dv/dt = pi cos pi t C)1/pi D) cos 0 = 1 so at t = 0 , 1 , 2 etc E) ...
November 25, 2016

second graph link not rights
http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=8d8e2c27bcaa121d6ee0de4b98774bb4&title=Polar%20Graphs&theme=blue&i0=r%3D2(2-sin^2%C9%B5)^%C2%BD%20&i1=0&i2=Pi%2F2&podSelect=&showAssumptions=1&showWarnings=1
November 25, 2016

calculus
I suspect you mean: r=2(2-sin2?)^½ that makes me nervous that since you do not type exponents you might mean 2-sin^2 ? instead of what your typed. I will assume that first graph it here with sin 2? http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=...
November 25, 2016

Science
mass = 150/g or about 15 kg but who needs it? x = A sin w t v = Aw cos wt a = -Aw^2 sin wt = -w^2 x ============================= when x = .2 = A sin w t v = 5 = Aw cos w t a = +20=+Aw^2 sin w t = +w^2x =============================== so w^2 x = w^2(.2) = 20 w^2 = 200/2 = 100 ...
November 24, 2016

Maths
x^2 y = V G = 4x+y = 6 ================== y = 6-4x x^2 (6-4x) = V now do the complete the square thing like I did in your other problem to find the vertex of the parabola
November 24, 2016

Engineering
4 x = 800 x = 200 feet on a side square ========================= prove that square is max area A = x y P = 2 x + 2 y perimeter so x + y = P/2 A = x (P/2 - x) = -x^2 +P/2 x x^2 - (P/2) x = A find vertex,complete square x^2 - (P/2)x + P^2/16 = -A + P^2/16 (x-P/4)^2 = -(A-P^2/16...
November 24, 2016

math
s = standards d = deluxe 12 s +18 d = 360 ____divide by 6 s + d = 25 ________multiply by 2 2 s + 3 d = 60 2 s + 2 d = 50 -------------- d = 10 then s = 15
November 24, 2016

Physics
assume you mean 5 m/s^2 50 *1000/3600 = 13.9 m/s v = 13.9 - 5 t 0 = 13.9 - 5 t t = 13.9/5 average speed during stop = 13.9/2 d = (13.9/2) (13.9/5) or d = Vi t - .5 (5) t^2 d =13.9(13.9/5)-.5 (5) (13.9^2)/5^2 = .5 *13.9^2/5 the same
November 24, 2016

physics
ub^2 = .25 ua^2 average speed for initial slowing = .5(ua+ub) assume constant a t = .05/.5(ua+ub) = .1/(ua+ub) v = Vi +at ub = ua + a t ub-ua = a (.1)/(ua+ub) .1 a = -(ua^2-ub^2) .1 a = - (.75 ua^2) a = -7.5ua^2 now complete trip 0 = ua + a t t = ua/7.5ua^2 = 1/(7.5ua) d = Vi...
November 24, 2016

Math
There are lots of different ways. perhaps the easiest to understand uses the distributive property 12 = 10 + 2 13 = 10 + 3 (10 + 2) (10 + 3) = 10 (10+3) + 2 (10+3) = 100 + 30 + 20 + 6 = 100 + 50 + 6 = 156 ========================== You can shorten that by saying 10(13) + 2(13...
November 24, 2016

Physics
If there is no moment (torque) then there is no change of angular momentum [ I omega = constant] If they are not opposite in direction through the same point, they cause a moment, called a "couple"
November 24, 2016

algebra
n and 2 n 2 n - n = 20 n = 20 and so answer = 2n = 40
November 23, 2016

Gaussian Elimination Method
LOL, forgot the old easy stuff :)
November 23, 2016

Gaussian Elimination Method
to check, put it back in -4(-1) -(-2) = ? yes 6 12(-1) -2(-2) = ? yes -8
November 23, 2016

physics
m v^2/r horizontal m g down tan theta = mg/(mv^2/R)where theta is angle down from horizontal but cos theta = .7/2.8 so theta = 75.5 deg so tan theta = 3.87 so 3.87 = mg/mv^2/R = 9.81/(v^2/.7) v = 1.33 m/s m v^2/R = .4*1.77/.7 = 1.01 m g = .4*9.81 = 3.92 T^2 = 1.01^2 +3.92^2 T...
November 23, 2016

Math
9*10^-3 LY (5.88*10^12 mi/LY) = 52.92 * 10^9 mi = 5.292 * 10^10 mi
November 23, 2016

math!
q = first questions/min 2 q = final que/min t min for first ten 48 - t min for final 11 q t = 10 so t = 10/q q t + 2q(48-t) = 21 10 + 96q - 20 = 21 96 q = 31 q = 31/96 questions/min so twice that = 62/96 to finish ======================== check t = 960/31 = 30.97 min 48-t = 17...
November 23, 2016

Algebra 2
.75 x + .42 y = .5784 (100) x+y = 100 ============================ .75 x + .42 y = 57.84 .75 x + .75 y = 75 ---------------------- -.33 y = - 17.16 y = 52 x = 48 E
November 23, 2016

Physics
h f = 14.7 eV lambda = c T = c/f c about 3*10^8 m/s
November 23, 2016

Physiscs
well the length is L sqrt 13 but who cares? force up from floor = m g = 3g (because wall is smooth none up there) force sideways from wall = F thus force sideways at floor = F toward wall Now moments about center clockwise mg * 2L/2 = m g L counter clockwise F*1.5 L + F*1.5 L...
November 23, 2016

physics
80 km/hr * 1 hr/3600s * 1000 m/km = 22.2 m/s tan T = v^2/r / g = v^2/gr tan T = 22.2^2/(981) tan T = .502 T = 26 deg 39 min
November 23, 2016

Physics
rho g h 1000 * 9.81 * 20 = 196,200 Pascals = 1.94 atm gage (over 1 atm) or 2.94 atm absolute
November 23, 2016

Physics
done already
November 23, 2016

Calculus
Oh, but I said where x = +/- infinity
November 23, 2016

Calculus
Oh, yes :)O
November 23, 2016

Calculus
Oh my, look around x = 0 and x = 1 and x = infinity and x = -infinity http://www.wolframalpha.com/input/?i=plot+1%2F(x(x-1))
November 23, 2016

Math
a) sin is + in I and II b) cos is - in II so there only c) hard to sketch here from origin up 7 distance 25 x^2 + 7^2 =625 and x is - x^2 = 625 - 49 = 576 x = -24 so point is at (-24,7) cos C = -24/25 tan C = -7/24
November 23, 2016

Math
cos /sin = -1 = cotan 90 + 45 360 - 45
November 23, 2016

Consider the linear programming problem
You are welcome.
November 23, 2016

Consider the linear programming problem
which we could have seen without doing the problem :) The potato seed costs less and the profit is more
November 23, 2016

Consider the linear programming problem
maximize 150 x + 50 y x + y <=70 20 x + 60 y <= 3000 x>= 0 y>= 0 x+y >=1 to fill in input form only http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=1e692c6f72587b2cbd3e7be018fd8960&title=Linear%20Programming%20Calculator&theme=blue result 10500 at (70,0)
November 23, 2016

Calculus
f' = 10 - 10/x^2 f" = 0 - 10 [ -2/x^3] = 20/x^3 I do not see anyplace where the curvature passes through zero except at x = +/- infinity
November 23, 2016

Linear Programming to Maximize Profit
You are welcome.
November 23, 2016

Linear Programming to Maximize Profit
Oh my heavens I have done so many linear programming problems tonight! s uses 6 plastic d uses 3 plastic so 6 s + 3 d </= 300 s uses 4 metal d uses 8 metal so 4 s + 8 d </= 608 s </=22 maximize 10 s + 2 d I get 332 at (22,56) using http://www.wolframalpha.com/widget/...
November 23, 2016

math
7x = 1.40 x = .20 2x = 0.40 4x = 0.80 5x = 1.00 7x = 1.40 sum = $3.60
November 23, 2016

simplex method
For instructions using Simplex with pivots etc see http://en.wikipedia.org/wiki/Simplex_algorithm
November 23, 2016

doing with linear programming
http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=1e692c6f72587b2cbd3e7be018fd8960&title=Linear%20Programming%20Calculator&theme=blue max = 3220 at (12,50)
November 23, 2016

Calculus
This is a closed path check first if field is potential in which case integral is zero F = z^2 i + 2xy j + 3y^2k del cross F = 0 ???? nope no way so first line = 3 i + 0 j + 0 k F dot line = Fx *3 = 0*3 = 0 second line in x from 3 to 3 = 0 in y from 0 to 3 = 3 in z from 0 to 1...
November 23, 2016

Calc
or rather curl F
November 23, 2016

but still think MITx
:)
November 23, 2016

Calc
curve is ellipse at z = 11 and 5, y = 0 and x = +/-3 (-3 , 0 , 11) (+3 , 0, 5) at z = 8 , x = 0 and y = +/-3 The normal to that ellipse is in he x z plane and is perpendicular to the line joining(-3, 0 ,11)and (3,0,5) slope of that original line dz/dx = -6/6 = -1 remarkable so...
November 23, 2016

MITx
Just asking :)
November 23, 2016

Calc
You doing an MITx subject?
November 23, 2016

Calc
curl of F over the surface curl is i j k d/dx d/dy d/dz fx fy fz is =(dFz/dy-dFy/dz)i +(dFx/dz-dFz/dx)j +(dFy/dx-dFx/dy)k here Curl F =(ex-9x)i +(y-ey)j +(9z-z)k
November 23, 2016

Calc
Flux = int over S of F dot [1i - (dz/dx)^2j -(dz/dy)^2k] F dot [i -4x^2 j - 4y^2 k] [xy - 4x^2yz -4y^2xz]dx dy now put in 2 -x^2-y^2 for z and do the integrals from 0 to 1
November 23, 2016

physics
if boy at 1 meter girl at (4/3) meter
November 23, 2016

physics
50 N * .2 m = 10 Nm
November 23, 2016

The Graphical Method
I get 40 of A, 0 of B for profit = 1000 maximize 25 x + 15 y constraints 5x+4y<=300 2x+3y<=108 x>=0 y>=0 x+y>=1 (phony to fill fields)
November 23, 2016

linear programming
http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=1e692c6f72587b2cbd3e7be018fd8960&title=Linear%20Programming%20Calculator&theme=blue try that while I look at your problem
November 23, 2016

Algebra 2 (Please help Ms. Sue!)
292 ?
November 23, 2016

Algebra 2 (Please help Ms. Sue!)
f(x)/(x-a) = f(a) here a = -3 so we need f(-3) f(-3) =(-3)^4-9(-3)^3-5(-3)^2-3(-3)+4 = 81 + 9*27 - 45 +9 + 4 = 81 + 243 - 45 + 9 + 4
November 23, 2016

Linear Programming
note, to make the program format happy I put in max 180x+60y x+y</=60 20x+10y<=700 x>=0 y>=0 x+y>=1 phony but fills boxes
November 23, 2016

Linear Programming
a+b<=60 20 a + 10b </= 700 a and b >=0 maximize 180 a + 60 b intersections at 0,60 35,0 10,50 at a = 0, b = 60 180 (0) + 60 *60 = 3600 at a = 10, b = 50 180(10) + 60(50) = 4800 at a = 35, b = 0 180(35) = 6300 so plant 35 acres of a and zero of b. Use the whole $700 ...
November 23, 2016

Linear Programming
http://www.wolframalpha.com/widget/widgetPopup.jsp?p=v&id=1e692c6f72587b2cbd3e7be018fd8960&title=Linear%20Programming%20Calculator&theme=blue
November 23, 2016

Gaussian Elimination Method
+5 -4 12 divide by 5 to get 1 -5 +3 +9 +1 -4/5 12/5 multiply by 5 and add -5 +3.0 +9 +1 -4/5 12/5 +0 -1.0 21 multiply by -1 +1 -4/5 12/5 +0 +1.0 -21 so y = -21 now multiply second eqn by 4/5 and add to first +1 -4/5 12/5 +0 +4/5 -84/5 +1 +0 -72/5 +0 +1 -21 x = -72/5, y = -21
November 23, 2016

Physics
sure, if you use a seesaw, you must be twice as far from the pivot point as the weight is. You must move twice as far down as the weight moves up. (draw geometry) You could use a pulley with one end of the line attached to the ceiling, then running down through the block on ...
November 23, 2016

Calculus
depth = h dV/dh = area of surface (draw it :) dV/dh = pi r^2 = surface area r = (2.7/4.3)h remember to use chain rule. for example dV/dt = 59.5 m^3/min but dV/dt = dV/dh dh/dt so dh/dt = 59.5/ (pi r^2) etc
November 23, 2016

Science
Now what American mammal is marsupial?
November 23, 2016

Science
eg: http://www.ucmp.berkeley.edu/mammal/marsupial/marsupial.html
November 23, 2016

Science
google kangaroo, marsupial :)
November 23, 2016

help me plz
I wish I knew what rt{t} meant but anyway we will need to do r of 9 and delta r for delta t at t = 9 r = t i + t^1.5 j + e^.25 t k dr/dt= i + 1.5 t^.5 j + .5 e^.25 t so dr (your delta r) = dt i + 1.5 t^.5 dt + .25 e^.25 t dt j Then r(9)= 9 i + 27 j+ 9.49 k dr = dt i + 4.5 dt j...
November 23, 2016

calculus
The DOMAIN is all real t HOWEVER the RANGE is only from -1 to +1 in i and -4 to + 4 in j and all real numbers in k
November 23, 2016

History
NO !!!!
November 22, 2016

science
Senpai - buying books instead of borrowing from the library uses up trees (as well as a lot of other stuff like fuel).
November 22, 2016

science
Which do you think Jaden? Think of the effect of each answer on trash heaps and energy supplies and forests.
November 22, 2016

Science
initial momentum = 1 kg * 7 m/s - 2 kg * 7/6 m/s = = 14/3 kg m/s final momentum is the same 14/3 = 1 * V1 + 2 * V2 so V1 = 14/3 - 2 V2 initial Ke = (1/2)(1)(49) + (1/2)(2)(49/36) final Ke = .75*initial Ke = (1/2)(1)V1^2 + (1/2)(2)V2^2
November 22, 2016

PHYSICS PLEASE HELP ME
force of gravity down slope = m g sin 30 = .5 m g force of friction up slope = FF use FF to get angular acceleration FF r = I alpha so alpha = FF r/I = FF r/(2/5 mr^2) alpha = 5FF/2mr FF = 2 m r alpha/5 a = r alpha so alpha = a/r and F = m a so m a = .5 m g - FF m a = .5 m g...
November 22, 2016

math
I do not know what your triangle looks like area outside triangle = circle area pi r^2 - triangle area
November 22, 2016

maths
volume of sphere = (4/3)pi r^3 pi R^2 h = (4/3) pi r^2 h = (4/3) r^2/R^2
November 22, 2016

maths
just like your other problem, your turn
November 22, 2016

Physics- Equilibrium
If I had to pick one it would be c. Constant velocity means no acceleration which means no net force.
November 21, 2016

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