Sunday
May 24, 2015

Posts by Damon


Total # Posts: 21,035

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

physics
radial A = v^2/r tangential A = 7.9 they are perpendicular |A| = sqrt ( v^4/r^2 + 7.9^2 )
April 17, 2015

Maths
2/3 * 600 = 400 so 200 left after T shirt then 1/5 * 200 = 40 so 200 - 40 = 160 left to go home with
April 17, 2015

math
Any other line that intersects that one will do. It can not be the same line and it can not be parallel. You have -3 x + 2 y = 4 so change the sign of the x coefficient for example which changes the slope. +3 x + 2 y = 4 Now you have -3 x + 2 y = 4 +3 x + 2 y = 4...
April 15, 2015

Pre - CALCULUS
y = 5 x - 3 as x goes to 5 y ---> 22
April 15, 2015

Physics
Same answer as your other question.
April 15, 2015

Physics
eg: http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-007-electromagnetic-energy-from-motors-to-lasers-spring-2011/lecture-notes/MIT6_007S11_lec38.pdf
April 15, 2015

Physics
Google Heisenberg uncertainty principle certainty of product of position and momentum is limited so the more accurately you know position the less accurately you know momentum
April 15, 2015

nope
not without knowing the water temp at start
April 12, 2015

physics
power = voltage * current 20,000 * 50 = 500,000 i i = 50 (2/50) = 2 amps That is why you send big power at high voltage
April 12, 2015

LINEAR EQUATIONS
There is a limit to how many people I can help at once.
April 12, 2015

LINEAR EQUATIONS
c = a + b x or 100 = a + b(20) 122.5 = a + b(25) -------------------- 22.5 = 5 b b = 4.5 100 = a + 4.5*20 a = 10 so y = 4.5 x + 10 ----------------- now check if 25 wraps y = 4.5*25 + 10 = 122.5 sure enough
April 12, 2015

Math
However here the sum of any two must not be less than the third side or they will not reach b fails c fails d fails ONLY A passes :)
April 12, 2015

math problem HELP ME
Look at this scroll down to "algebraic proofs" http://en.wikipedia.org/wiki/Pythagorean_theorem
April 12, 2015

math problem HELP ME
(a-b)^2 + (4 a b/2) = a^2 - 2 a b + b^2 + 2 a b = a^2 + b^2 but as you know c^2 = a^2 + b^2 is the Pythagorean Theorem
April 12, 2015

Math
tan 40 = h/5 not much of a tree :)
April 12, 2015

physics
no your torque is not constant from 0 to 1 second it is Torque = 2 t for 0 to 1 second a = 2 t/2.5 v = (2/2.5)(t^2/2) = 1/2.5 rad/s at 1 second ------------------------ NOW that is your constant torque of 2 from 1 second to 2 seconds initial v = 1/2.5 rad/s a = dv/dt = 2/2.5 v...
April 12, 2015

Vectors
1) x = 1 + 2 s or s = (x-1)/2 y = 7 + 5 s y = 7 +(5/2)(x-1) 2y = 14 + 5 x - 5 5 x - 2 y = -9 now where does that hit 2) ? t = (x-3)/4 so y = (10/4)(x-3) + 12 4 y = 10 x - 30 + 48 10 x - 4 y = -18 so we have two equations 5 x - 2 y = -9 10 x - 4 y = -18 BUT THEY ARE the SAME ...
April 12, 2015

physics
Actually, I took the course in 1956 and do not need the practice. You do. Try and I am sure one of us will look your results over.
April 12, 2015

math
$1000 in and $400 out :) chance of winning = 1/500 value = 400/500 = 80 cents
April 12, 2015

Algebra 1
You are welcome.
April 12, 2015

Algebra 1
h = t (64-16 t) h is zero, ground, when t = 0 and when t = 4 t may not be - t may not be greater than 4 unless the arrow drops into a mine shaft so I would say 0</= t </= 4
April 12, 2015

typo ?
do you mean -16 t^2 + 16 t + 32 ???? all t, no x that in the obsolete foot, pounds, slugs units is the height of a projectile under gravitational force only. In that case 32 is the initial height in feet when t = 0
April 12, 2015

Science
thrust = rate of change of momentum mass per second in = 40 momentum per second in = 8000 mass per second out = 42 momentum per second out =42*600 = 25200 change of momentum per second = 17200 kg m/s^2 which is 17200 Newtons By the way, that is Newton #2 which you know better ...
April 12, 2015

Physics
Q = flow rate = pi r^2 V loses rho g h = 1000 kg/m^3 * 9.81 m/s^2 * 5.2 m in N/m^2 or Pascals it will go faster through the smaller pipe so loses pressure by Bernoulli Q2 = Q = pi r^2 V2 so V2/1.8 = 6.5^2/5.5^2 calculate V2 then pressure loss due to v increase is (1/2)(1000) (...
April 12, 2015

Algebra 2 A
y^2 + 6 y = 3 x - 3 y^2 + 6 y + 9 = 3 x + 6 (y+3)^2 = 3 x + 6 (y+3)^2 = 3 (x+2) vertex at (-2,-3) open to right
April 12, 2015

Physics
what is the period when the resonance occurs? T = distance/speed = 5 / 6.1 m seconds so frequency f = 1/T = 6.1/5 Now do your sqrt K/m thing
April 12, 2015

Math
hey ANY 2 dimensional figure if its scale is multiplied by x its AREA is multiplied by x^2 2^2 = 4 or in this case 2L * 2 w = 4 L w
April 11, 2015

Math
(4/3) pi r^3 = (4/3)pi(8) = 33.51 m^3 (1/3)(pi)(4)^2 (10) = 167.6 m^3
April 11, 2015

Math
3*36 + 2*12 + 8 = 140 inches (Sheila) 24*12 + 8 = 296 inches (record) =296-140 = 156 inches longer 156/12 = 13 feet longer
April 11, 2015

algebra
0/5 = 0 5/0 is very, very very big try on your calculator 5/ 0.00000001
April 11, 2015

pre - CALCULUS
34/5 + 11/5 + z = 9 ? z = 9 - 9 = 0 2 * 34/5 - 3 * 11/5 + 4z = 7 7 + 4 z = 7 z = 0 ah ha, B -7 z/5 + 2 z/5 + z IS ZERO LOL Talk about fooling the student !
April 11, 2015

ah ha
34/5 11/5 undefined 0 can not solve for z, bottom row all zero put arbitrary z in and see what happens
April 11, 2015

pre - CALCULUS
whoops, 2 not three in row 2 beginning put in +1 +1 +1 +9 +2 -3 +4 +7 +1 -4 +3 -2
April 11, 2015

pre - CALCULUS
Those answer choices are wrong
April 11, 2015

pre - CALCULUS
put in +1 +1 +1 +9 +3 -3 +4 +7 +1 -4 +3 -2 3 rows, 4 columns
April 11, 2015

pre - CALCULUS
0 , 29/7 , 34/7 it says http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
April 11, 2015

pre - CALCULUS
strange answer choices, arbitrary z hang on
April 11, 2015

pre - CALCULUS
http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
April 11, 2015

pre - CALCULUS
But there is a limit to what I am going to try to type
April 11, 2015

pre - CALCULUS
oh ho, now Gauss Jordan. We are cooking with gas here
April 11, 2015

Pre - CALCULUS
LOL, I have not finished You need to do the whole ting all you know is termm 11 and 21 so far whoops 12 not +12 so element 11 is 5/12 and element 21 is -1/6 looks like C
April 11, 2015

Pre - CALCULUS
left determinant is D = -12 first solution is for +1 -6 +0 -5 or -5/12 = element 11 then +0 +1 -2 +0 over -12 or 2/-12 = -1/6 = A21 then do the second
April 11, 2015

Pre - CALCULUS
well, it may be time to ask what method you are supposed to use. for example you seem to have Cramer's rule so A * A*-1 = 1 0 over 0 1 so solve with 1 over 0 on the right then with 0 over 1 on the right so for first column of inverse solve +0 x - 6 y = 1 -2 x - 5 y = 0 ...
April 11, 2015

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