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March 25, 2017

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Posts by Damon

Total # Posts: 29,622

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

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

Physocs- Components of Resultant Vectors
A = 5 i - 3 j B = 5 i + 4 j --------------- C = 10i + 1 j
November 21, 2016

Physics- Accleration of a Falling Penny
google terminal velocity
November 21, 2016

Physics
Sorry for the long explanation. I am a naval architect and this subject is close to me :)
November 21, 2016

Physics
It is true if the body is floating. The force upward from the water is equal to the weight of the water displaced. If the body is floating, that water weight must be equal to the weight of the body and the body rises in the water until that is true. That is how ships float. If...
November 21, 2016

Physics- Baseball thrown upwards, accleration
THE ENTIRE TIME the acceleration is one g, about 9.8 m/s^2 downward. In other words yes, b
November 21, 2016

Statistics
http://davidmlane.com/hyperstat/z_table.html
November 21, 2016

Physics-Tension Force
infinite
November 21, 2016

Physics
.4 N up 9.8*.145 down m a = .4 - 9.8*.145 that is about .4 - 1.4 or -1 a = -1/.145 = about -7 a
November 21, 2016

Science
I replied .
November 21, 2016

Math
9 3/4 = 39/4 39/4 / 3/4 = 39/4 * 4/3 = 39/3 = 13
November 21, 2016

TIP MATH!
well Ms Sue used the fact that 15% is halfway between 10% and 20% I used a tenth plus half of a tenth. same difference :)
November 21, 2016

TIP MATH!
10% + 5% = 15% 2.3 + half of that 2.3 + 1.2 = 3.50 ps the accurate answer is 3.49
November 21, 2016

Maths help asap please.
n (n+1) + n+1 n^2 + n + n + 1 n^2 + 2n + 1 = (n+1)(n+1)
November 21, 2016

Physics
d = speed * time d = (100 km/60 min) * 5 min d = 25/3
November 21, 2016

Science plsss help!
4) I suspect is B 5) .5^6 = .0156 = 1.6 % agree second number 5, really that fast?
November 21, 2016

Physics
one of those two speeds is negative
November 21, 2016

math
sin ? = 1/1.25 tan ? = sin ?/cos ? = 1/v
November 20, 2016

physics
sqrt (100 + 16) = sqrt 116 = srt (4*29) = 2 sqrt(29) tan angle above x axis = 4/10 |a| = (1/.5) *2 sqrt 29 = 4 sqrt 29 at same tan^-1(.4)
November 20, 2016

calculus antiderivation
Vi = 60 mi/h * 5280 ft/mi /3600 s/h Vf = 45 * 5280/3600 Vf = Vi - 11 t solve for t =========================== 0 = Vi - 11 T T = Vi/11 d = Vi T - 5.5 T^2
November 20, 2016

Math
1.5/6 = x/16 x = 16 * 1.5 / 6
November 20, 2016

Maths trigonometry
tan 30 = 150/x
November 20, 2016

factor of 2
for part b .5 m g (d+x) = .5 k (x)^2 + .5 m v^2 we know d from part a m v^2 = m g d + m g x - k x^2 m v dv/dx = m g - k x dv/dx = 0 at max v k x = m g
November 19, 2016

Physics
You are welcome.
November 19, 2016

Physics
Not that easy m g (d+.23) sin 30 = .5 k (.23)^2 sin 30 = .5 so m g (d+.23)= k (.23)^2 3.2 (9.8)(d+.23) = 443 * .23^2 =========================== for part b m g (d+x) = k (x)^2 + .5 m v^2 we know d from part a .5 m v^2 = m g d + m g x - k x^2 m v dv/dx = m g - 2 k x dv/dx = 0 ...
November 19, 2016

Physics
Slides (d + .23) total m g (d+.23) sin 30 = .5 k (.23)^2
November 19, 2016

math - business
The y intercept is where x = 0 so -12,000 is correct The x axis intercepts are when y, the profit, = 0 that is when x = 2 and z = 15 correct the 15 is from 6000 - 400 x = 0 x = 60/4 x = 15
November 19, 2016

Math Help
probability of no boys = .5^5 so probability of one or more than 1 = 1 - .5^5 = .969
November 19, 2016

calc
so displacement is zero and distance is 5.33 + 15.75 + 10.42 = 31.5 check my arithmetic !!!!
November 19, 2016

calc REPAIR of displacement
v = t^3 - 10 t^2 + 27 t - 18 integral = t^4/4-10t^3/3 +27t^2/2 -18t at 7 integral = -7.58 at 1 integral = -7.58 so displacement = 0
November 19, 2016

calc
I used this to do the numbers: http://www.mathportal.org/calculators/calculus/integral-calculator.php t = 1 to t = 3 int = +5.33 t = 3 to t = 6 int = -15.75 t = 6 to t = 7 int = +10.42 so distance = -21.5 this also says my answer for part 1 should have been 5.33 -15.75+10.42...
November 19, 2016

calc
(t-1)(t-3)(t-6) = 0 so 1 to 3 then 3 to 6 then 6 to 7
November 19, 2016

calc
integrate to find x(1) and x(7) x(7)-x(1) is the displacement vector to find the distance scalar we must know when the particle is moving forward and when back and integrate over those intervals adding absolute values v = t^3 - 10 t^2 + 27 t - 18 integral = t^4/4-10t^3/3 +27t^...
November 19, 2016

Calc
integral of (500-3t) = 500 t - 1.5 t^2 at t = 13, integral = 500(13)-1.5(169) = 6500 - 253.5 = 6246.5 liters
November 19, 2016

Math
integer
November 18, 2016

Math
Are you sure you mean sqrt(-9) ??? That is an imaginary number. Maybe you mean sqrt (25-9) = sqrt (16) which is 4 which is a whole number and an integer
November 18, 2016

Math
5 + sqrt -9 5 + 3 sqt(-1) 5 + 3 i complex
November 18, 2016

math
m < 13 n > 13 p < 5 I think you mean at most 35 people 20 + a <= 35 a <= 15 so no more than 15
November 18, 2016

watch units!
watch out, km/hour given
November 18, 2016

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