Sunday
April 19, 2015

Posts by damon


Total # Posts: 20,912

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

Pre - CALCULUS
I mean 9 :)
April 11, 2015

Pre - CALCULUS
+2 +4 -1 +1 -2 +2 ---> -4+40-1 -10-4-4 = 17 yuuk +5 +1 +1 now solve for Y not x because your solutions set has all different y values :) +2 32 -1 +1 -5 +2 ---> --10+320-20 -25-80-32 = 153 +5 20 +1 then 153/17 = ( whew, D
April 11, 2015

pre - CALCULUS
yes -4 * -1 = 1 and -4*3 = -12
April 11, 2015

pre - CALCULUS
note the determinant of 2 1 6 3 is 6 - 6 = 0 therefore the solutions using Cramer's Rule are undefined
April 11, 2015

physics
volume of iron = (4/3)pi (Rout^3-Rin^3) mass of iron = (1 g/cm^3)(4/3) pi Rout^3 so density of iron = Rout^3/(Rout^3-Rin^3)
April 11, 2015

math
18(4/3) = 24
April 11, 2015

maths
10^x * 10^y = 10^(x+y) (to multiply add exponents if the base is the same)
April 11, 2015

NEED HELP PHYSICS!!!
Ac = v^2/r = v^2/10.5 F = m Ac 3.22 = .0822 v^2 /10.5 solve for v
April 11, 2015

PHYSICS HELP PLEASE !!
F = m a tension = mg + m v^2/r F = 78.4 (9.81 + v^2/10)
April 11, 2015

Calculus(urgent please help)
vertical asymptotes is easy because x = 3 or -3 makes function undefined where is slope + and where - ? slope = ([x^2-9]2x - x^2[2x])/[x^2-9]^2 denominator is always + or 0 when is top + and -? top is -18x so slope = -18x/positive number so slope is + if x is + and - if x is...
April 10, 2015

pre - CALCULUS
You are welcome.
April 10, 2015

pre - CALCULUS
continuous A = P e^rt A = 11,000 e^(.065 *10) A = 11,000 * 1.9155 semiannual 20 periods at .0315 per period (6.3/2) 1.0315^20 = 1.859 A = 11,000 * 1.859 which is less :(
April 10, 2015

Pre - CALCULUS
well, I can not graph it very well but if exponential then y = Ae^kx x = year - 1985 12 = A e^0 = A(1) = A so y = 12 e^kx in 1994, x = 9 years y = 12 e^9k = 145 e^9k = 145/12 = 12 9 k = ln 12 = 2.48 k = .276 now in 2002 we would get x = 17 then we would get y = 12 e^(17*.276) ...
April 10, 2015

Pre-calculus help
tan is - in quadrants 2 and 4 cos is + in quadrants 1 and 4 so we are in quadrant 4, x = 6, y = -1 hypotenuse = sqrt (37) cute tan 2x = 2 tan x /(1-tan^2 x) = 2 (-1/6) /(1 - 1/36) =-(1/3) / (35/36) = -12/35 well that was easy now we better find out what quadrant 2x is in x is ...
April 10, 2015

pre - CALCULUS
so did I
April 10, 2015

pre - CALCULUS
Hey, I just did it.
April 10, 2015

pre - CALCULUS
to add two vectors you can add the components in orthogonal (perpendicular) directions and the sum will have components in those directions if u = a i + b j and v = c i + d j then u + v = (a+c) i + (b+d) j now here u+v = (-4+4) i + (1+1) j or 0 i + 2 j which is magnitude 2 in ...
April 10, 2015

pre - CALCULUS
I am not sure I understand your symbol. (absolute value?) anyway u + v = 2 j the magnitude of 2 j is 2
April 10, 2015

Math 222
Well, I told you number line eg so x is left of -3 or right of +2
April 10, 2015

Math 222
You are welcome.
April 10, 2015

Math 222
12 - x > 15 -x > 3 multiply both sides by -1 BUT change direction of arrow when changing signs x < - 3 (LOL - again) 7 x - 13 > 1 7 x > 14 x > 2 so x is left of -3 or right of +2
April 10, 2015

Math 222
divide it up into two problems 12 <12+ 4x 4 x >0 or x >0 and 12+4x <0 4 x < -12 x < - 3 so x is either left of -3 or right of 0 on a number line
April 10, 2015

pre - CALCULUS
The new graph has a point at (0,2), not at (0,0) The new graph has slopes of 2 and -2 instead of 1 and -1 in other words translate up[ 2 and double the slopes of the V shape
April 10, 2015

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