Saturday
July 4, 2015

Posts by Damon


Total # Posts: 21,408

Math and Phyics
Tension T in rope, on big mass M g - T = M a while the big mass is falling, the little mass goes up a distance h when the big mass hits ground, the little mass is moving with the speed that the big mass hits with, then coasts up until the kinetic energy of that speed is spent...
December 22, 2014

Math/Algebra 1
string = 180 + 2 (necklace) if necklace = 10 string = 180 + 20 = 200 if necklace = 11 string = 180 + 22 = 202 if necklace = 12 string = 180 + 24 = 204 etc works fine
December 22, 2014

Math/Algebra 1
string = 200 + 2 (length of necklace - 10) or string = 180 + 2 length of necklace)
December 22, 2014

redone
v = 256 pi/3 = (4/3) pi r^3 so r = 4 S = v(3/r) = 4 pi r^2 = 64 pi v = (4/3) pi r^3 = S (r/3) = (1/3) S r dv/dt = (1/3) [ S dr/dt + r dS/dt ] but S dr/dt = dv/dt = 10 30 = 10 + 4 dS/dt 20 = 4 dS/dt dS/dt = 5 cm^3/s
December 22, 2014

Calc
V = (4/3) pi r^3 so when V = 256 * pi/(3) 256 pi/(3 ) = 4 pi r^3 /(3) r^3 = 64 r = 4 d v = surface area of sphere * dr dv = 4 pi r^2 dr = 64 pi dr dv/dt = 64 pi dr/dt = 10 cm^3/s dr/dt = 10/(64 pi) so dV/dt = 4 pi r^2 dr/dt = 10 so dr/dt = 10/(4 pi ) dS/dt = 8 pi r dr/dt = 32 ...
December 22, 2014

Math and Phyics
Is there no picture?
December 22, 2014

Math and Physics - Huh ?
There are two masses M and m ? They are at two vertices of the triangle? What is at the third corner?
December 22, 2014

algebra
You are welcome :)
December 22, 2014

algebra
check -2(8) - 7 -16 - 7 -23 sure enough :)
December 22, 2014

algebra
-2 v - 7 = -23 add 7 to both sides -2 v = -23 + 7 = -16 divide both sides by -2 v = -16/-2 = +8
December 22, 2014

AP CALC
sin 3 pi/2 = sin 270 = -1 sin - 3 pi/2 = +1 change in sin x = -1 - +1 = -2 change in x = 3 pi/2+3pi/2 = 3 pi so slope from left to right = -2 / 3pi = -.2122 so where does the derivative of sin x = -.2122 ? d/dx (sin x) = cos x so cos x = -.2122 x = 102.25 degrees = 1.78 radians
December 21, 2014

Physics
if initial speed in +x direction impulse = change of momentum .0420 (-7.4 - 18.3)
December 21, 2014

ap calc
when x = 2, y = 2(4)-8+3 = +3 when x = 0, y = 2(0) -0^2 = 0 delta y/delta x = (3-0)/2 = 1.5 so where in there does f' = 1.5 ? between 0 and 1 f' = 2 - 2x so 2 - 2x = 1.5 2x = .5 x = .25 is one spot between 1 and 2 f' = 4 x - 4 so 1.5 = 4 x - 4 4 x = 5.5 x = 1.375 ...
December 21, 2014

Physics
call + x direction the initial direction of the first (3 kg) mass initial momentum = 3*2 -5*2 =6-10 = -4 final momentum also -4, mass = 8 8 * v = -4 v = -1/2
December 21, 2014

ap calc
h = e^sin x h' = cos x e^sin x cos pi/2 = 0 sin pi/2 = 1 so 0 * 1 = 0
December 21, 2014

been there done that
I just did this a little while ago
December 21, 2014

math
0.34* 10^7 + 4.7 * 10^7 = 5.04 * 10^7 but you are only using 2 significant figures so 5.0 * 10^7
December 21, 2014

math i really need help!!
5.93 * 10^5 - 0.271 * 10^5
December 21, 2014

College Math
probably sqrt (30)
December 21, 2014

physics
Now this is very similar but easier than the one you threw up from the roof of the building. You try it. I have grand kids playing hockey now.
December 21, 2014

physics
That t top in part B is the time to slow down on the way up from the top of the building to the max height. 10/9.81 seconds. THEN, it starts falling from that top point I called Htop. By the way it will pass the roof on the way down at 10 m/s down :)
December 21, 2014

physics
v = Vi - 9.81 t v = 0 at top so t = 10/9.81 at top (part B) Htop = 150 + 10 t - 4.9 t^2 (part A) now simply drops from Htop to ground Pe at top = m g Htop Ke at bottom = (1/2) m v^2 so v = sqrt (2 g Htop) (part C) we have original t rising to top now time falling v = 0 + g ...
December 21, 2014

math
6/9 = 2/3 chance of not blue on each pick if replaced, then independent 2/3 * 2/3 * 2/3 = 8/27
December 21, 2014

algebra
2 s + 5 a = 950 s+a = 250 so a = 250 - s 2 s + 5 (250-s) = 950
December 21, 2014

Physics- revolutions
Ac = v^2/r so .7 = .013 v^2/.93 solve for v we know r time = distance / speed = 2 pi r/v
December 21, 2014

phys
F = m a = 70 * acceleration = 70 * 5 * 9.81
December 21, 2014

Physics~
You are welcome :)
December 21, 2014

Physics~
sqrt (ge/gm) = sqrt 6 times period on earth
December 21, 2014

Physics
.145 * 9.81 - .4 = 1.022 N down a = F/m = 1.022/.145 = 7.05 m/s^2 down I get
December 21, 2014

Static Friction..I really Have no Idea
maximum friction force = mu m g = .2 * .4 * 9.81 = .787 Newtons so it is less than or equal to .787 Newtons (or .78 N if you use 9.8 for g and round to two significant figures)
December 21, 2014

chemistry
p V = n R T p/RT = n/V = constant here n of H2/V of H2 = n of NH3/V of NH3 V of H2 = (n of H2/ n of NH3)100 cm^3 for every 2 mols of NH3 you get 3 mols of H2 so n of H2/n of NH3 = 1.5 so V = 1.5 * 100 = 150 cm^3
December 21, 2014

Physics
T - m g = m a T = 10.0 (9.81 + 1.50)
December 21, 2014

Math
8 + 3 = 11 37 + 15 = 52 so 11:52 pm
December 21, 2014

Wolfram disagrees with me, check my algebra
http://www.wolframalpha.com/input/?i=plot+xln%28x%29%2B+%281-x%29ln%281-x%29
December 21, 2014

ap calc
y = x ln x + ln(1-x) - x ln (1-x) = ln x^x + ln [ (1-x)/(1-x)^x = ln [ x^x (1-x)^1/(1-x)^x ] = ln [ x^x (1-x)^(1-x) ] let z = 1-x dz = - dx y = ln [ x^x z^z ] = ln x^x + ln z^z = x ln x + z ln z y' = x (1/x) + ln x + z(1/z)dz/dx + ln z dz/dx = 1 + ln x -1 - ln(1-x) = 0 all...
December 21, 2014

ap calc
y = sin x y' = cos x I guess that is -3 pi/2 to + 3 pi/2 sin 3 pi/2 = -1 sin -3 pi/2 = 1 -1 - 1 = -2 -1/(3 pi) = -.1061 cos^-1 -.1061 = 96.1 degrees = 1.677 radians cos is odd function so also -1.677 radians
December 21, 2014

History
He sent General Zachary Taylor to claim an area of disputed land for the United States. http://en.wikipedia.org/wiki/South_Pass_%28Wyoming%29 The journey was surprisingly easy. the idea that it was God's plan for the nation to expand across the continent
December 21, 2014

Math-How do I do this problem?
sure change in volume = surface area * change in depth or dV = pi r^2 dh dV/dt = pi r^2 dh/dt = 12 ft^3/min so dh/dt = 6/(pi r^2) if r = 7, h = 24 or r = (7/24)h = (7/24)(10) = 70/24 so dh/dt = 6 / [ pi (70/24)^2 ]
December 21, 2014

physics
two arrows right, one left <-.------>-->
December 21, 2014

physics
yes
December 21, 2014

multiplcation
6*1000 = 6000 6*700 = 4200 6*50 = 300 6 * 0 = 0 ------------------add 10500
December 21, 2014

math
p = price of kerosene/liter 5 p/3 = price of diesel 5 p = price of petrol x = liters of diesel purchased cost of x liters of diesel = 5 x p/3 = 510 cost of x liters of kerosene = x p but x p = (3/5)(510) = 306
December 21, 2014

Calculus
6 x dx + 2 y dy = 0 dy/dx = -3 x/y at (1,2) this is-3/2 d^2y/dx^2 = -3 [ y - x dy/dx ]/y^2 at (1,2) = -3[2+3/2]/4
December 21, 2014

calculus
ln y = 3 x ln (x+8) (1/y ) dy/dx = 3x[1/(x+8)] + 3 ln(x+8) dy/dx = 3x(x+8)^3x {[1/(x+8)]+3 ln(x+8)}
December 21, 2014

Calculus
dy/dx = 2 x so -1/slope = -1/2x = -1/4 y = -x/4 + b 9 = -1/2 + b b = 9.5 y = -x/4 + 9.5 4 y = -x + 38
December 21, 2014

Math
dy/dx = 3 x^2 + 10 x -8 yes 0 d^2y/dx^2 = 6 x + 10 positive so min at 0 I get about .2 so not 0 so I think only A
December 21, 2014

Physics- Horizontal Velocity
You dropped it from 5 meters and it went 25 meters maybe ?? If so: time to drop 5 meters 5 = (1/2)(9.8)t^2 t = 1.43 seconds u = 25 m/1.43 s = 17.5 m/s
December 21, 2014

Biology
Sometimes mechanical (rubbing) , sometimes chemical (reacting with O2), etc. The one thing you can count on is that whatever happens, it will end up losing heat to the environment :)
December 19, 2014

physics please help
Bart does 400/60 m/s how many meters does he do in 58 s ? (when Wyatt finishes) 400 (58/60) = 386.66666666666666666667 400 - that = 13.3333333333 meters
December 19, 2014

NEED HELP ASAP PHYSICS
35.79 miles per hour { Google 16 m/s = miles/hour } a = change in velocity/change in time = -16/.08 = -200 m/s^2
December 19, 2014

did that
see question above
December 19, 2014

physics
stuff shoots out the rear, body moves forward Conservation of momentum (Newton #1) initial momentum before reaction = 0 so momentum of body/exhaust system remains zero forever therefore if exhaust moves back then body must move forward to keep the total momentum zero
December 19, 2014

Helppp
1 2 3 4 5 ---- 5.5 ---- 6 7 8 9 10 1 2 3 4 5 ----- 6 ----- 7 8 9 10 11 so A = 5.5 B = 6 11.5/2 = 5.75
December 19, 2014

math
No, .025*2,015,000 is the commission. You wrote what the seller gets after commission.
December 19, 2014

Juba Day SS
10/20 * 9/19 10/20 * 3/19 7/20 * 3/19
December 19, 2014

PRE-ALGEBRA MRS.SUE PLEASE!!!!!!!!!
Did you read my answer below? I have answered this question twice. 59.95/11.99 = 5 so you can buy 5 you can also buy four or three or two or one or none
December 18, 2014

PRE-ALGEBRA MRS.SUE PLEASE!!!!!!!!!
We can not always answer instantly.
December 18, 2014

PRE-ALGEBRA MRS.SUE PLEASE!!!!!!!!!
Check below you are fine except for #8 and #10
December 18, 2014

PRE-ALGEBRA
59.95/11.99 = 5 so you can buy 5 you can also buy four or three or two or one or none Please do not submit the same question twice !
December 18, 2014

PRE-ALGEBRA
1. 7 yes 2. 8 yes 3. 7x + 5 = 4x + 5 + 3x yes 5. k < 0 yes 6. q ≥ –1 yes 7. p < 8 yes 8. g > –90 #####I get g >90#### 9. n – 6 ≥ 2; n ≥ 8 yes 10. ??????? n </= 5 you could buy one or 4 but not 6
December 18, 2014

Algebra 1
since 7 x and -7 x appear just add the two equations to eliminate x like: 3 y = 3
December 18, 2014

Math
n/(n+1) (n+2) /[(n+1)+2 ] = 4/5 (n+2) / (n+3) = 4/5 5(n+2) = 4(n+3) 5 n + 10 = 4 n + 12 n = 2 2/3
December 18, 2014

Science yes, agree
Check my answers please? Imagine that you remove all the atoms from a chair. What remains? 1. nothing 2. a pile of dust I choose 1. YES Which of the following is not made of atoms? 1. heat 2. a solid 3. a gas I choose 1. YES What about matter is true? 1. atoms are not matter ...
December 18, 2014

Algebra 1
x-1 = -3x -5 4 x = -6 x = -1.5 y also negative yes quad three
December 18, 2014

math
or we could say 3/4 = Juice /(32-juice)
December 18, 2014

math
there are 3+4 = 7 parts
December 18, 2014

math
(3/7)32
December 18, 2014

statistics
http://davidmlane.com/hyperstat/z_table.html
December 18, 2014

algebra 1
use FOIL or distributive property (same thing really) 7 p^2 + 10 p + 3 or 7p (p+1) + 3 (p+1) = 7 p^2 + 7 p + 3 p + 3 = 7 p^2 + 10 p + 3 again
December 18, 2014

math
5 years = 20 quarters at .05/4 = .0125 per quarter 1.0125^20 = 1.282037232 so 55,000/1.282037232 = $ 42,900.47
December 18, 2014

Honors Physics
Try to answer and we will look.
December 18, 2014

Honors Physics
Honors physics?
December 18, 2014

algebra 1
10 x - 24 y = -6 10 x - 4 y = -25 ----------------- 0 x - 20 y = 19 y = -19/20 etc
December 18, 2014

phy
a up on 6 kg mass, so down on 10 kg mass 6 kg mass T - 6 g = 6 a 10 kg mass 10 g - T = 10 a add 4 g = 16 a a = g/4 then go back T - 6 g = 6 g/4 T = 7.5 g = 7.5(9.81)
December 18, 2014

algebra
40 + n = 10 + 4 n 30 = 3 n
December 18, 2014

Math
.65 * 80 100 (.65*80)/327
December 18, 2014

Math
(4x-1)/[(x+3)(x+4)] * (x+4)(x-3)/(2x-1) the (x+4) cancels, not much else to do
December 18, 2014

Math
I think it just blows up if x = -3
December 18, 2014

Math
x(x-2) /(x+1) * (x+1)(x-1)/[(x+3)(x-2)] = x (x-1)/(x+3)
December 18, 2014

math solution on algebra
half this triangle is a 30, 60, 90 triangle with the altitude (sqrt 3) as the long leg and half(1) the base as the short leg. (1/2) b h = (1/2)(2) sqrt 3 = sqrt 3
December 18, 2014

physics
Vi = 54 sin 39 v = Vi - 9.8 t v = 0 at top so t = Vi/9.8 at top use that t h = Vi t - 4.9 t^2 it will turn out to be 1/2 Vi t
December 17, 2014

Please look for reply before posting again
I did that a lot of questions ago.
December 17, 2014

physic
http://www.jiskha.com/display.cgi?id=1418842081
December 17, 2014

physic
been there, done that
December 17, 2014

calculus honor
assume you mean y = 2 x^3 - 4 x dy/dx = 6 x^2 - 4 if x = 1 dy/dx = 6-4 = 2
December 17, 2014

calculus honor
V = x^2 h dV/dx = 2 x h dV/dh = x^2 dV/dt = dV/dx dx/dt + dV/dh dh/dt x = 4 h = 15 dV/dt = 120 dx/dt + 16 dh/dt = 120(2) -16(3) = 240-48
December 17, 2014

done that
I did this one a while ago as well :(
December 17, 2014

calculus
A = pi r^2 A/dr = 2 pi r (which is the circumference of course, draw a circle and a ring of thickness dr on the outside and look at the added area) if r = 5 dA/dr = 10 pi =================== this is most interesting if the radius is changing with time r = k t dr/dt = k dA/dt...
December 17, 2014

physic
power = work/time work = weight * distance up = 475*9.81*10 so power = 475*9.81*10 / 24 Joules/second or Watts divide by 1000 for kilowatts
December 17, 2014

Math( Can you help me with starting this problem)
dV/dr = area of surface = 4 pi r^2 so dV/dt = 4 pi r^2 dr/dt so dr/dt = (dV/dt) / (4 pi r^2)
December 17, 2014

Physics
If .392 Newtons is pulling it at constant speed then the friction is equal and opposite to the pull .392 = mu m g = mu (.2219)(9.81)
December 17, 2014

Algebra
height = 5 (L-10)(w-10)5 = 1760 (L-10)(w-10) = 352 L = 2 w (2w-10)(w-10) = 352 (w-5)(w-10) = 176 w^2 - 15 w + 50 = 176 w^2 - 15 w - 126 = 0 (w-21)(w+6) = 0 so w = 21 L = 42
December 17, 2014

Algebra 1
slope = m = 3 10 = 3 (2) + b b = 4 y = 3 x + 4
December 17, 2014

Physics
If the angle is 90 degrees to the x axis it is all y axis 0 i + 9 j
December 17, 2014

Science-Physics
500 * 5 force in direction of motion times distance moved
December 17, 2014

physics
300 * 9.81 * 6 Joules
December 17, 2014

Physics
500 cos 37 - .5 (350 + 500 sin 37) = m a m = 350/9.81 find a 4 = (1/2) a t^2 for part be find mu for: 500 cos 37 - mu (350 + 500 sin 37) = 0
December 17, 2014

Physic
potentials add Q1/r = Q2/(.5-r)
December 17, 2014

physics
g = 9.81 m/s^2
December 17, 2014

Physics
51 = 4.9 t^2 solve for t d = 31 t v = 9.81 t vertical and 31 horizontal so speed = sqrt ( v^2+31^2)
December 17, 2014

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