Tuesday
October 21, 2014

Posts by damon


Total # Posts: 18,972

math
I (we) did not use any resources such as the web or books other than our textbook. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; and you want me to work on it ?
October 19, 2014

Physics
Total momentum = 0 Mb*2.2 - Me*2.9 = 0 Mb/Me = +2.9/2.2 the ratio of masses is unlikely to be negative and I think you have it upside down.
October 19, 2014

Physics!
force = rate of change of momentum (only m a if m is constant :) change of momentum = 79.1 (0 - -6.27) change of time = 2.06*10^-3 s so force = + 6.27*79.1 / .00206 Newtons
October 19, 2014

Calculus
You are welcome.
October 19, 2014

Calculus
In other words you got the slope right but did not get b right in y = m x + b
October 19, 2014

Calculus
you say y = 5 x + 2.5 then if x = pi/4, y = 5 pi/4 + 2.5 You say but what is f(x) at x = pi/4 ??? sin^2 = 1/2 2 tan = 2 so f(x) = 2.5 You better take 5 pi/4 off your answer
October 19, 2014

Physics
Keb = (1/2)55 (7.5^2) = 1545 J = 1.55kJ I agree with your book :)
October 19, 2014

Physics
55*22 = 1210 = 55 Vb cos 76+ 45 Vs cos 12 45*26 = 1260 = 55 Vb sin 76 - 45 Vs sin 12 1210 = 13.3 Vb + 44.0 Vs 1260 = 53.4 Vb - 9.36 Vs times 44/9.36 1210 = 13.3 Vb + 44.0 Vs 5922 = 251 Vb - 44.0 Vs ------------------------- 7132 = 264.3 Vb Vb = 27 km/hr = 7.5 m/s humm, we ...
October 19, 2014

physics
force in = mg sin 12 = m v^2/r v^2/r = g sin 12 turns 180 deg = pi radians r = v^2/(g sin 12) pi r = distance flown = pi v^2/(g sin 12) time = distance / speed = pi r/v = pi v/(g sin 12 here v = 450/3.6 and g = 9.81
October 19, 2014

physics
m = 5 t^.8 - 3 t + 20 dm/dt = (5*.8) t^-.2 - 3 so at max or min 0 = 4/T^.2 - 3 T^.2 = 4/3 = 1.333 .2 log T = log 1.333 Log T = .6246 T = 10^.6246 = 4.21 seconds find m at t = 4.21 and find dm/dt at 3 and 5 (signs better be different)
October 19, 2014

Math
You are welcome.
October 18, 2014

Math
A + B = 500,000 .14 A + .10 B = 59,000 multiply second equation by 10 1.0 A + B = 500,000 1.4 A + B = 590,000 --------------------- subtract -.4 A = -90,000 A = 225,000 etc
October 18, 2014

Math
A + B = 260,000 A = B + 77,000 so B + 77,000 + B = 260,000 or 2 B = 183,000 etc
October 18, 2014

Math
Yes, it is a quadratic equation
October 18, 2014

Math
been there, done that see below
October 18, 2014

math
LOL, well if 6 is the answer then -16(36) + 96 (6) better be zero is it ? :)
October 18, 2014

Math
yes, quadratic equation
October 18, 2014

Math
speed before Forde = (s-5) speed after Forde = s time to Forde = (t+96) note 4 days = 96 hr time after Forde = t then distance = speed * time 70 = (s-5)(t+96) 60 = s t or t = 60/s 70 = (s-5)(60/s + 96) 70 = 60 + 96 s - 300/s - 480 490 = 96 s - 300/s 245 = 48 s - 150/s or 48 s^...
October 18, 2014

Physics
v = Vi + a t d = Vi t + (1/2) a t^2 2240 = 199 t + 4.25 t^2 solve quadratic for t then v = 199 + 8.5 t
October 18, 2014

Physics
d = (1/2) a t^2 176 = 4.35 t^2 solve for t v = a t = 8.7 t
October 18, 2014

PHYSICS 1301 (COLLEGE)
When people do not even go back and see if what they typed makes any sense, I just skip to the next question.
October 18, 2014

Calculus
v = -gt = -9.8*2 100 = 4.9 t^2 t = 4.52 seconds to ground so v = -9.8*4.52
October 18, 2014

chemistry
.55 a = .45(715)
October 18, 2014

calculus
4 cos anything is never bigger than 4 so there is no overlap here
October 18, 2014

Calculus
2 * L + 4*w = 800 so L = 400 - 2w A = L * w A = (400 -2w)w A = -2 w^2 +400 w dA/dw = 0 at max = -2 w + 200 w = 100 L = 400 -200 = 200
October 18, 2014

Calculus
decrease at start due to startup costs and paying off initial investment in staff and equipment increase over long term because we have to go deeper and deeper into the vein as we mine out the easy stuff near ground level.
October 18, 2014

Chemistry
heat it 25 deg C 550 * 2.03 * 25 Joules
October 18, 2014

physics please help
In the end torque = F*.4 - friction torque = I d omega/dt
October 18, 2014

physics please help
Not knowing that frictional torque, I am at a loss. Please proof read question.
October 18, 2014

Physics
69 v1 = 47 v2 so v2 = (69/47)v1 19 = (v1+v2)t 19 (v1 + 1.47 v1) t so v1 t = distance of first = 19/2.47 = 7.69 meters
October 18, 2014

Physics
same old conservation of momentum at first p = 2 *1 + m * 4.4 at the end p = (2+m) * 1.5 so (2+m)(1.5) = 2 + 4.4 m 3 + 1.5 m = 2 + 4.4 m etc
October 18, 2014

DIFF CALCULUS
now the volume is another story because now we will have to make some assumption, for example constant slope up from 3 m to 1 m. In that case we have a trapezoid and V = 6 * 12 * average depth = 6 * 12 * 2 - 144 m^3
October 18, 2014

DIFF CALCULUS
Part b is easy and requires no assumptions about the shape of the pool bottom. The rate of change of height = volume added per second / surface area of water. (draw a picture) or dh/dt = .25 m^3/min / (12m*6m) = .00347 m/min or 21 cm/hour
October 18, 2014

Algebra typo
22x maybe? what is the question anyway? factor it? put in an equal sign and solve it find zeros of parabola ? by the way x^2 + 22 x + 121 = (x+11)^2 (x+11)^2 -y^2 = (x+11-y)(x+11+y) because a^2-b^2 = (a-b)(a+b)
October 18, 2014

physics
if v = 0, p = 0 v ground = sqrt (2 g h) momentum at ground = m v = 4 sqrt (2 g h)
October 18, 2014

physics
falls from top for 6.65/2 = 3.325 seconds h = (1/2) (9.8) (3.325)^2
October 17, 2014

MATH HELP PLEASE
no sqrt 36 = 6 but what is sqrt 21 ?
October 17, 2014

Last ratio/equation
m/w = 10/12 so w = 12 m/10 then w/c = 10/15 12 m /10 / c = 10/15 12 m/c = 100/15 = 20/3 m/c = 20/36 = 5/9
October 17, 2014

equations
a/b = 5 so b = a/5 use that in the second a/5 / c = 2/3 multiply by 5 a/c = 10/3
October 17, 2014

equation
divide both sides by 3b 3a/3b = 5b/3b simplify a/b = 5/3
October 17, 2014

Science-Physics
y velocity = 8.9 x velocity = 19.3 tan theta = (8.9/19.3)
October 16, 2014

Science (Physics)
acceleration = change in velocity / change in time same as speed on the way up, but down not up or in other words it falls from 3 meters up m g h = (1/2) m v^2 so v = -sqrt(2 g h) = -sqrt ( 2 * 9.81 * 3)
October 16, 2014

Algebra
LOL - It happens
October 16, 2014

Algebra
for heaven's sake subtract: 1.10 - 1.05 = ?????? 1.15 - 1.10 = ??????
October 16, 2014

physics
I hope and pray we are talking about buoys and not boys. Anyway, here is a solution for totally immersed spheres. If the sphere waterlines are halfway down the sphere, then double the resistance. (you have half as much conductance) http://www.df.unipi.it/~macchi/TEACHING/...
October 16, 2014

normal distribution
http://davidmlane.com/hyperstat/z_table.html
October 16, 2014

Algebra 2
Now that point (5,6) 5 is beyond x = 3.5 so on the way down y = (7/2)(5)- (1/2)(25) = 10/2 = 5 will not make it over wall
October 15, 2014

Algebra 2
y = (7/2) x - (1/2)x^2 reasonable domain is above ground, y>0 so solve for zeros of x x^2 -7x = 0 x = 0 to x = 7 range (vertex is when x = half 7 or3.5 ymax = (7/2)(7/2) -(1/2)(7/2)^2 = (1/2)(49/4) = 49/8 = 6.125 so range is 0 to 6.125
October 15, 2014

Algebra 2 well, maybe
well, maybe y = a + b x + c x^2 3 = a + b(1) + c(1) 5 = a + b(2) + c(4) 6 = a + b(3) + c(9) so 2 = b + 3 c 1 = b + 5 c ---------- 1 = -2c c = -1/2 1 = b -5/2 b = 7/2 3 = a + 7/2 -1/2 = a + 3 so a = 0 y = 0 + 7 x/2 - x^2/2 y = (7/2) x - (1/2)x^2 or 2 y = 7 x - x^2
October 15, 2014

Algebra 2
y = a + b x^2 3 = a + b (1)^2 = a + b 5 = a + b(2)^2 = a + 4 b b = 3 - a 5 = a + 4(3-a) 5 = a + 12 - 4a 3 a = 7 a = 7/3 b = 9/3 - 7/3 = 2/3 so y =7/3 +2/3 x^2 check last point y = 7/3 + (2/3)(9) = 7 1/3 I do not think your table is a parabola
October 15, 2014

Pre-Calc/Trig...
v = Vi - g t at top v = 0 0 = 4 -32 t t = 1/8 second (4 ft /sec is really slow. I bet you mean 40) h = 10 + 4 (1/8) - 16 (1/64) = 10 + .5 - .25 = 10.25 ft
October 15, 2014

science
both the same ( Newton #3 action equal and opposite to reaction) F = G * 6 * 7.3 / .65^2 where G = 6.67 * 10^-11
October 15, 2014

Math
maybe ln y = ln 35.15 + 1.04 x
October 15, 2014

Algebra 2
332/2 = 166 = v+c 318/2 = 159 = v-c 2 v = 166+159 = 325 etc
October 15, 2014

Math 112
(86 + 88 + z)/3 = 90 86 + 88 + z = 270 etc
October 15, 2014

Pre-Calc/Trig...
(2x-1)(x+3) = 0 --> 1/2 and -3 x^2 - x - 1 = 0 x = [1 +/- sqrt (1+4) ]/2 = 1/2 +/- (1/2) sqrt 5
October 15, 2014

Physics Help Please!!!!
the mass of the shuttle is decreasing because fuel is being expelled F = m a same F less m more a Same happens with your car, but so slowly it does not matter :)
October 15, 2014

physics... PLEASE HELP
F = m a = 9 * 10^13 * 1.7 * 10^-27 = 15.3 * 10^-14 = 1.5 * 10^-13 Newtons
October 15, 2014

physics
R = 1.3 * 10^7 * 8 * 10^-9 ohms/m^2 i = V/R b. Same V, double R, half i
October 15, 2014

physics... PLEASE HELP
The relation between the energy and the momentum is E = p c where p is momentum so our momentum density here is our energy density/c
October 15, 2014

physics... PLEASE HELP
well, it is late but I might be able to point a direction average intensity = average power / (pi r^2) Peak = twice average power if a sine wave [ average of sin^2 = (1/2) ] energy density usually in Joules per square centimeter where it hits I assume per second. That would be...
October 15, 2014

Physics - Second Law Question
same as the other question (3-1.96)10^5 Newtons up
October 15, 2014

Physics - Second Law Question
4.9 - 4.5 = 0.4 0.4*10^-3 = 4 * 10^-4 down because weight is bigger than drag up
October 15, 2014

Physics
NO!! Usually in a given problem the SUM of kinetic and potential energy is more or less constant. I say more or less because energy is easily lost from your nice neat problem through friction or escape of heat or whatever messy thing happens to make your car not coast forever ...
October 15, 2014

Math
(7/8)hr/(3/4) puzzle = 7/6 hours/puzzle or 6/7 puzzles/hour
October 15, 2014

Pre-Calc/Trig...
b^2-4ac 5^2 -4(2)(-3) that will be positive and therefore its square root is a real number. Thus two real roots, nothing imaginary about it 1^2 - 4(-1)(1) everything positive again, two real roots
October 15, 2014

Physics
x momentum after = x momentum before after p = 38 (6.06 cos 10.5) + 2.37 v before p = (38+2.37)(5.07) set equal, solve for v which will probably be negative (kid goes forward, board goes backward)
October 15, 2014

Pre-Calc/Trig...
4 sqrt -1 = 4i 7 sqrt -1 = 7i
October 15, 2014

Math
do you mean??? [(-3) ^-4 ] [ 5 ^-2 ]=? if so [1/(-3^4 )] (1/25) (1/81)(1/81)(1/25)
October 15, 2014

Algebra 2
1+6+11 = 18 = 2/3 of cast so cast = 27 27 - 18 = 9 which is indeed 1/3 of the cast
October 15, 2014

Algebra 2
cost = c Briana + 73 = c Molly + 65 = c Briana + Molly = c so molly = (c - Briana) now we have Briana + 73 = c (c - Briana) + 65 = c or Briana = 65 Briana + 73 = c 73 + 65 = c = 138
October 15, 2014

Science
been there, done that http://www.jiskha.com/display.cgi?id=1413411282
October 15, 2014

Mechanics
x velocity = 15 across y velocity = .9 downstream note order of answers c. time to cross = 500/15 = 33.33 seconds b. downstream y = .9 * 33.33 = 30 meters a. sqrt (.9^2+15^2) angle to x axis = A = tan^-1(.9/15) d. sin^-1 (.9/15) toward upstream e. component of speed across = ...
October 15, 2014

math
n-2, n, n+2 4(n-2) - n = 12 + 2(n+2) 4 n - 8 - n - 12 - 2n - 4 = 0 n - 24 = 0 n = 24 22 , 24, 26
October 15, 2014

Math
let z = cos A 4 z^2 - 3 z = 0 z(4z-3) = 0 z = 0 or z = 3/4 so cos A = 0 when z = 90 degrees cos A = 3/4 when z = 41.4 degrees but that is not between 90 and 180
October 15, 2014

Algebra Help
(2x+5)^.5 - (x+6)^.5 = 1 you mean maybe, parentheses missing if so (2x+5)^.5 = 1 +(x+6)^.5 2x+5 = 1 + 2 (x+6)^.5 + x+6 (x - 2) = 2 (x+6)^.5 x^2 - 4 x + 4 = 4 x + 24 x^2 - 8 x - 20 = 0 (x-10)(x+2) = 0 x = 10 or x = -2 go back and see what works in the original now.
October 15, 2014

algebra
1. let z = x^2 then yo have 4 z^2 - 4 z + 1 (2z-1)(2z-1) which is (2x^2-1)(2x^2-1) 2. a^2 (a^2+1)
October 15, 2014

algebra
(x+3)(x-2) 3*5 = 15 which differs from 113 by 2 so (3x-1)(2x+5)
October 15, 2014

Linear Algebra
.866 is sin 60 by the way
October 13, 2014

Linear Algebra
L1 = 1 L2 = -.5 - .866 i L3 = -.5 + .866 i eigenvectors messy see http://www.wolframalpha.com/widgets/view.jsp?id=9aa01caf50c9307e9dabe159c9068c41
October 13, 2014

Algebra 2 Answer Check
just put in a bunch of cost values from 0 to 10 if the cost were $2 change = 8 cost - change = 2 - 8 = -6 and 10 - 2(8) = -6 It is only non-negative if the cost is between 5 and 10
October 13, 2014

Algebra 2 Answer Check
I misread it cost = 10 - change cost - change = 10 - 2 change
October 13, 2014

Algebra 2 Answer Check
Huh f(x) = 10 - x
October 13, 2014

Algebra 2
You are right, there is no solution to #1
October 13, 2014

Algebra 2
Oh, I see, you are right. no positive divided by -5 could be + 6
October 13, 2014

Algebra 2
-26/3 is negative 34/3 is positive but they could both be negative anyway
October 13, 2014

Algebra 2
By the way to graph that parabola y = 5 x^2 - 8 x + 11/3 http://www.wolframalpha.com/input/?i=5+x^2+-+8x+%2B+11%2F3
October 13, 2014

Algebra 2
1. (|3x -4|)/(-5) = 6 A: no solution ========================= multiply both sides by - 5 , no arrow business because just an equal sign 3 x - 4 = -30 or -3x + 4 = -30 3 x = -26 or -3x = -34 so there are two solutions
October 13, 2014

Algebra 2
6. |12 - 4x| - 4 > 20 A: x < -3 and x > 9 ============================ 12 -4 x > 24 or -12 + 4x >24 -4x > 12 or 4x > 36 x < -3 or x > 9
October 13, 2014

Algebra 2 #1 sorry
1. (|3x -4|)/(-5) = 6 (|3x -4|) = -30 or 3x-4 = -30 or -3x+4 = -30 so x = -26/3 or x = 34/3
October 13, 2014

Algebra 2
5. (-3) x (|5x - 8|)- 5 greater than or equal to 6 A: no solution? ============================ 3 (-3) x (|5x - 8|)- 5 >/= 6 (-3) x (|5x - 8|) >/= 11 x (|5x-8)| </= -11/3 x(5x-8) </= -11/3 x(-5x+8) </= -11/33 5 x^2 - 8 x </= -11/3 -5 x^2 + 8 x </= -11/3 ...
October 13, 2014

Algebra 2
4. [(|x - 2|)/ (4) greater than or equal to 5 A: -18 < x < 22 =========================== x-2 >/=20 or -x+2 >/= 20 x >/= 22 x </= -18
October 13, 2014

Algebra 2
3. |5x + 15| > 20 A: x > 1 and x < -7 5x +15 > 20 or -5x - 15 >20 x > 1 yes -5x > -35 divide both sides by -5 and reverse the arrow x < 7 why the sign ?????
October 13, 2014

Algebra 2
2. (|2x -5|) = x + 3 A: x = 8 or x = 2/3 ========================= 2x-5 = x+3 or -2x+5 = x+3 x = 8 or x = 2/3 you got that right. Why did you miss #1 ????
October 13, 2014

Algebra 2
1. (|3x -4|)/(-5) = 6 (|3x -4|) = -30 or 3x-6 = -30 or -3x+6 = -30 so x = -24/3 = -8 or x = 12
October 13, 2014

Math
2 sin T cos T cos T /sinT = 2 cos^2 T
October 13, 2014

algebra
a circle with radius 10 and center at (7,6) (x-7)^2 + (y-6)^2 = 10^2 = 100 where does it hit the y axis (y=0) ? (x-7)^2 + 36 = 100 (x-7)^2 = 64 (x-7) = +/- 8 x = 7 +/- 8 if x = 7+8 then x = 15 if x = 7-8 then x = -1
October 12, 2014

Physics
The lighter one had to be going faster. To be at 45 degrees, momentum north = momentum east 2000 v = 3000 (2v/3)
October 12, 2014

Physics 12
u = 12 cos 42 = 8.92 m/s the whole time Vi = 12 sin 42 = 8.03 v = Vi - 9.81 t h = 9.5 + Vi t - 4.9 t^2 0 = 9.5 + 8.03 t - 4.9 t^2 t = [ -8.03 +/- sqrt (8.03^2-4*-4.9*9.5)]/-9.81 t = [-8.03+/-sqrt(251) ]/-9.81 t = 2.43 s
October 12, 2014

calculus
a = area = 6 x^2 da/dx = 12 x so da = 12 x dx
October 12, 2014

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