Thursday
September 3, 2015

Posts by damon


Total # Posts: 21,884

mechanics: spring problem
In total the block fell from 3 to 1 meters off floor so change in gravitational potential m g h = m g (2) there it is stopped so that energy is now stored in the spring which compressed half a meter m g (2) = (1/2) k x^2 = 80 (1/4) = 20 so 20 m = 20 m = 1 kg
September 3, 2015

mechanics: spring problem
I just did one problem from you, the xo and vo sping
September 3, 2015

Physics
Initial ke = (1/2)(.05)(400)^2 Final Ke = (1/2)(.05) (50)^2 so work done = (1/2)(.05)( 400^2-50^2) = force * distane = 40,000 T solve for T
September 3, 2015

Pre Calculus
V = 4.50 (t-5) + Vi where Vi is the initial 2005 value
September 3, 2015

mechanics: simple harmonic oscillation
x = a sin w t + b cos wt v = a w cos wt - b w sin w t omega = w = sqrt(k/m) at t = 0 x = -xo v = dx/dt = vo - xo = b + vo = a w or a = vo/w so x = (vo/w) sin w t - xo cos wt now I could say magnitude (or amplitude) = sqrt (vo^2/w^2 + xo^2) which is max motion from equilibrium...
September 3, 2015

Algebra
The y intercept is where the line hits the y axis. That is when x = 0 so y = 0 x + b = b The x intercept is where the line hits the x axis. That is when y = 0 0 = a x + b so x = -b/a (That is why a can not be equal to 0. If it were the x axis intercept would be undefined. This...
September 3, 2015

Elementary Euclidean Geometry(Math)
Elementary Logic :) hypothesis - if a cow, then a mammal if true then converse - if a mammal then a cow Not sure ( It is the converse we have here :) inverse - if not a cow, then not a mammal Not sure contrapositive - if not a mammal, then not a cow True.
September 2, 2015

ALGEBRA
7 x^2 + x^2 = 8 x^2
September 2, 2015

Pre-Calc
Looks good to me. All you really have to do is remember that pi radians = 180 degrees.
September 2, 2015

Pre-Calc
-780 + 360 = -420 once around -420 + 360 = -60 twice around -60 + 360 = 300 sure enough
September 2, 2015

Math ?
I have no idea.
September 2, 2015

Math
If you replace, then the drawings are independent. 16 + 11 + 9 + 15 + 8 + 20 = sum green = 15 so p(green) = 15/sum
September 2, 2015

MATH
Oh, and remember that sum of angles in parallelogram is 360
September 2, 2015

MATH
3 x + 2 x + (3/2) x = 180 now try
September 2, 2015

ALGEBRA
7 x^2 + x^2 = 8 x^2 The first one was correct.
September 2, 2015

ALGEBRA
8 x^2 - 5 x + 1.5 y
September 2, 2015

Astronomy
You walk faster than you run, typoo I think 15 min * 60 s/min = = 900 seconds 12 min * 60 s/min = 720 seconds You spent 1620 seconds on this crazy trip You went 900*3.8 = 3420 720*2.5 = 1800 so 5220 meters 5220meters/1620seconds = 3.22 m/s
September 2, 2015

factorisation i need cerious itz too difficult
sorry (x^2 + y^2)
September 2, 2015

factorisation i need cerious itz too difficult
Try dividing by (x^2 + 2 y^2)
September 2, 2015

precalc
3) slope = m = 2 5 = 2*2 + b b = 1 so y = 2 x + 1 4) slope = m = -1/1 = -1 so y = -x + b 4 = 2 + b b = 2 so y = -x + 2
September 1, 2015

math
1166 2/3 I mean
September 1, 2015

math
Now you know the math way and the science way :)
September 1, 2015

math
1 3/4 = 7/4 inch 7/4 inch*(500 miles/.75 inch) = 1167 2/3 miles 14" (500mi/.75") = 9333 1/3 mi etc
September 1, 2015

Math
12.6666666666..... is greater than 12.63
September 1, 2015

algebra
well, try 84 (80 + 88 + x)/3 = 84 168/3 + x/3 = 84 168 + x = 252 x = 84 of course since that was original average now 89 80 + 88 + x = 3*89 = 267 168 + x = 267 x = 99 so 84 </= x </= 99
September 1, 2015

simultaneous equation very dificult need help itz urgent
a - c = b/2 a -c/6 = b -------------- subtract -5c/6 = -b/2 b = 5 c/3 so 5 c/3 + c = 32 8 c/3 = 32 c = 12 your turn
September 1, 2015

alGEBRA 1
10 days * 24 h/d = 240 h 240 h * 60 min/h = 14,400 min
September 1, 2015

Chem
mass of acid = 11.299-5.333 grams density = mass/volume = (11.299 - 5.333) g / 5 mL
September 1, 2015

MAT 221
nah d/6
September 1, 2015

Choctaw Middle School
3(16) + 4(10) = 48 + 40 = 88
September 1, 2015

Math
c = m h + b 55 = m (2) + b 65 = m (3) + b ------------------subtract -10 = -m m = 10 c = 10 h + b 55 = 20 + b b = 35 so c = 10 h + 35 if h = 6 c = 60 + 35 = 95
September 1, 2015

Travis elementary school
123 :)
September 1, 2015

Maths
5500 = 495 x - 475 x + 4950 550 = 20 x x = 27.5
September 1, 2015

Maths
x*475 + 10*550 = (x+10)*495
September 1, 2015

math
a numerical amount.
September 1, 2015

Physic
That's better R for 2 and 3 in parallel = 2*3/2+3 = 6/5 as we said before If 4 ohm is in series with those then add R total R = 6/5 + 4 = 26/5 current through 4 ohm = all of it = 20/R = 20*5/26 = 100/26 = 3.85 amps voltage across 4 ohm = 3.85*4 =15.38 V voltage across two ...
September 1, 2015

voltage?
1/2 + 1/3 = 1/R 3/6 + 2/6 = 5/6 so R = 6/5 Ohms now I have no idea what the 4 is. Another R in series? What is the voltage across what ?
September 1, 2015

math
500/3.3 = 151.5 miles per hour 300/2.5 = 120 miles/hour
September 1, 2015

Math
slightly different numbers, same problem http://www.jiskha.com/display.cgi?id=1441141046
September 1, 2015

Math
I just did this :(
September 1, 2015

Algebra
no x + 2 (2) = 3 x = -1
September 1, 2015

Algebra
multiply firat equation by 4 4 x + 8 y = 12 4 x + 5 y = 6 ----------------subtract 3 y = 6 y = 2 etc
September 1, 2015

Algebra
x axis intercept when y = 0 3/4 x = 3 x = 4 y axis intercept when x = 0 y = 3
September 1, 2015

math
a) 3, 4 , 5 is a common right triangle b) will not quite work 3 is long side 1 + 2 just barely stretches from end to end, just making a thicker three inch line :) c) misses by an inch. 7 + 12 = 19 which will not reach from end to end of 20 d) sure, why not - draw it
September 1, 2015

math
they have to add up to 8/8
September 1, 2015

Math
probability of first green = 8/20 probability of second green = 7/19 so (8/20)(7/19)
September 1, 2015

math
24 + 2 Z = ?
September 1, 2015

Pre-Calculus
eg https://www.khanacademy.org/math/algebra2/conics_precalc/parabolas_precalc/v/using-the-focus-and-directrix-to-find-the-equation-of-a-parabola
September 1, 2015

Pre-Calculus
This is a pure cookbook question and just follow the procedure in your text. We are here to help if you get stuck, not to do it for you.
September 1, 2015

Pre-Calculus
I already took the subject. You try.
September 1, 2015

Math
You are welcome.
August 31, 2015

Math
do it in seconds (30/26.2)( 1*3600 + 18*60 + 27) seconds = (30/26.2) (4707 seconds) = 5390 seconds take off one hour which is 3600 seconds 1 hour and 1790 seconds note 1790/60 = 29.83 so take off 29 minutes which is 1740 seconds 1 hour and 29 minutes and (1790-1740)seconds so ...
August 31, 2015

no table
pasting here does not work and we can not see your table of arrivals and departures.
August 31, 2015

U.S. History
They also tended to find good harbors, particularly at the mouths of rivers which gave them access to the interior. This was before the age of railroads, cars, trucks and planes so the fast and easy way to get around was by boat even if you did not have to take heavy cargo ...
August 31, 2015

math
0.25 is indeed 1/4
August 31, 2015

Algebra
a, b , c a+b+c=180 a = c/4 b = c-36 so c/4 + c-36 + c = 180 2.25 c = 216 c = 96 b = c-36 = 60 a = 24
August 31, 2015

Siyabusa secondary
for example see: http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/idegas.html
August 31, 2015

Siyabusa secondary
at stp one mol is 22.4 liters so 1.5 mol is 1.5 * 22.4 = 33.6 Liters
August 31, 2015

maths
Three out of every five are boys. 3/5 = x/40 multiply both sides by 40 8 * 3 = x x = 24 ========================== check that means 40 - 24 = 16 are girls 24/16 = 12/8 = 3/2 sure enough
August 31, 2015

typo
It is not 0.5 meter square Volume must be in meters CUBED It is probably a cube. but from what you wrote I can not say if you mean a cube with a square base with sides of 0.5 meter In which case we would have V = .5^3 = .125 m^3 or perhaps you mean V = 0.5 m^3 in either case V...
August 31, 2015

Math
Altitude h = 12 I think on one side you have a 5, 12, 13 right triangle and on the other a 9 , 12 , 15 right triangle (a 3,4,5 times 3) so average base = (11+25)/2 = 18 altitude = 12 area = 12 * 18
August 31, 2015

Algebra
agree
August 31, 2015

physics
The speed is horizontal at the top, call it u and it remains u all the way down because there is no horizontal force (acceleration). So we have a vertical problem first. v = g t h = (1/2) g t^2 so 33.2 = 4.9 t^2 t^2 = 6.77 t = 2.60 seconds so v = 9.81 * 2.6 = 25.5 m/s down ...
August 31, 2015

link better
http://www.google.com/search?q=hydrogen+radiation+spectrum+transitions&tbm=isch&tbo=u&source=univ&sa=X&ved=0CEwQsARqFQoTCO_83vy_08cCFcgyPgodLu8DCw&biw=1920&bih=971#imgrc=84jXbb3JhPIc3M%3A
August 31, 2015

CHEMISTRY
Here: https://www.google.com/search?q=hydrogen+radiation+spectrum+transitions&tbm=isch&tbo=u&source=univ&sa=X&ved=0CEwQsARqFQoTCO_83vy_08cCFcgyPgodLu8DCw&biw=1920&bih=971#imgrc=84jXbb3JhPIc3M%3A Look at all possible ways from 4 down to 1 such as 4 - 3 - 2 - 1 or 4 - 2 -1
August 31, 2015

Plus
10* 569 = 5690 2 * 569 = 1138 add those 12* 569 = 6828
August 30, 2015

Math
10 * 20 * 500 = 200 * (1,000/2 ) = 100 * 1,000 = 100,000
August 30, 2015

Science - physics
average speed during stop = 122/2 = 61 m/s to get time to stop v = 0 = 122 - 6.2 t t = 122/6.2 = 19.7 seconds so distance = v average * t = 61*19.7 = 1200 meters Off the end of the runway and 200 meters into the bleak ocean
August 30, 2015

Calculus
f' = sec x tan x + 2 sin x at x = pi/3 which is 60 deg f' = m = (2 * sqrt 3) + 2 (sqrt 3/2) so m = 3 sqrt 3 so y = 3 sqrt 3 * x + b at (pi/3 , 1) 1 = 3 (pi/3) sqrt 3 + b b = 1 - pi sqrt 3 so y = (3 sqrt 3) x + (1-pi sqrt 3) or approx y = 5.20 x - 4.44
August 30, 2015

Calculus
nothing wrong with that
August 30, 2015

MATH ALGEBRA
x = number of trees at year n at year 0, x0 = 7000 at year 1, x1 =.88*X0 + 600 = 6160+600 = 6760 at year 2, x2 = .88*x1 +600 = 6548.8 at year 3 , x3 = .88x2+600 = 6362.9 at year 4, x4 = .88*x3 + 600 = 6199.4 at year 5, x5 = .88*x4+600 = 6055.5 at year 6, x6 = .88*x5+600 = 5928...
August 30, 2015

math calculus
typo in second line .7 = e^-40 k
August 30, 2015

math calculus
a = A e^-kt .3 = e^-40 k ln .7 = -.357 = -40 k k = .008917 so 1/2 = e^-.008917 t if t is half life ln .5 = - .693 = -.008917 t t = 77.7 hours
August 30, 2015

math
Been there, done that: http://www.jiskha.com/display.cgi?id=1440890314
August 30, 2015

Calculus
If this is y = [ x^4 + x ]^.5 ?????? dy/dx = .5 [ x^4 + x ]^-.5 (4x^3 +1) = .5 (4x^3+1) /sqrt(x^4+x) ================================= if you mean y =( x^.5 )(x^3+1) y = x^3.5 + x^.5 dy/dx = 3.5 x^2.5 + .5 x^.5 /x = x^.5 ( 7 x^2 + 1/x)/2 = x^.5 (7 x^3 + 1) /(2 x) = (7 x^3 + 1...
August 29, 2015

Physics
Bug dv/dt = ab = 60 mi/h/2.4s = 25 mi/(s h) = 40.2 km /(3600 s^2) Sal dv/dt = as = 60/2.8 = 21.4 mi/(s h) =34.4 km/3600s^2 v = 75 km/h = 75 km/3600s then v = a t or t = v/a Bug: t = 75 km/3600 s / 40.2 km/3600s^2 = 1.87 seconds d = (1/2) a t^2 = OR use half max (average) speed...
August 29, 2015

SCIENCE!
1. - Did the rock chip hit him in the eye? 2. what mistake did Andrew make using measurement units? for density he needs VOLUME, not distance. He measured centimeters. He needs centimeters CUBED or cm^3 or cc 3. yes, write it in your lab notebook ! 4. I think he determined the...
August 29, 2015

math
I will try to reverse engineer what you are doing because I am not sure I understand you Say we are doing a compound interest problem. Yearly interest rate as a decimal is r For example 5% is .05 then every year I multiply what I have is the amount from the year before + r ...
August 29, 2015

Math
s^2 + 1 = (1/2)(4s) s^2 - 2 s + 1 = 0 (s-1)(s-1) = 0 s = 1
August 29, 2015

math
for exponential growth (continuous compounding) amount = original * e^rt rate = -.02 or -2 percent for example if you have ten dollars then after one year you will have 10 e^-.02 = 10(.980298) = nine dollars and eighty cents so each year multiply by .98 NOT 1.98 BUT that is an...
August 29, 2015

Geometry
5p^2-23p+24 well 24 = 4*6 or 3*8 or 2*12 or 1*24 so what might work in ( 5 p - %%) (p - %%) 15 and 8 is 23 so try 3*5 and 8 (5 p - 8)( p - 3 )
August 29, 2015

math
r = 0.06 meters A = pi r^2 F = 350,000 Newtons p = F/A = 350,000 /(pi *.06^2) in Newtons per square meter which is Pascals
August 29, 2015

pre-calculus
1) if it is really 4x = 3 then x = 3/4 a vertical line 2) 9y - 7 - 3y = 0 6 y = 7 y = 7/6 a horizontal line of slope 0 3) 7 x + 2 y = 14 2 y - -7 x + 14 y = -(7/2) x + 7
August 29, 2015

integral calculus
hmmm, graph that first function. sin a cos b = (1/2)sin(a+b)+(1/2) sin(a-b) (remember about beat frequencies :) so (1/2)[ sin(5x) dx - sin(x) dx ] ok? ======================================= let y = 3x then dy = 3 dx or dx = (1/3) dy so (5/3) [ cos^2 y dy ]
August 29, 2015

Science
agree
August 29, 2015

Physics
m = F/a
August 29, 2015

Physics
2*3600 seconds/h = 7200 seconds 75 * 7200 = 540,000 Joules total electricity use .7 * 540,000 = heat Joules .3 * 540,000 = light Joules
August 29, 2015

Math
x y = 15876 y = 9 x so 9 x^2 = 15876 x^2 = 1764 x = 42 =================== 169 + x^2 = 794 x^2 = 625 x = 25
August 29, 2015

Chemistry
150.01 - 104.70 = 45.31 grams of syrup .140 pint = 66.2 mL true so density = 45.31 grams/66.2 mL = 0.684 grams/mL = 0.684 grams/cubic centimeter
August 29, 2015

physics
work done on metal = m g h = .411*9.81*5.22 = 21.05 Joules 21.05 = .344 ke of hammer so ke of hammer = 61.2 Joulesd (1/2) 8.46 v^2 = 61.2 v^2 = 14.5 v = 3.80 m/s
August 29, 2015

physics
find bullet momentum from conservation of momentum .05 v = .55 * 4 = 2.2 then 2 V + 2.2 = 0 V = -2.2/2
August 28, 2015

physics
1.5*10^-4 = (1/2) (2.4*10^-4) v^2 so v^2 = 3/2.4 = 1.25 v = 1.11 m/s
August 28, 2015

physics
at takeoff Ke = (1/2) m v^2 = 1.5*10^-4 solve that for v work done = force * distance 1.5*10^-4 = .42 * distance
August 28, 2015

physics
change in potential energy = m g h the gravitation force is opposite to the direction of motion so work done = -m g h the escalator force is in the direction of motion so work done by it is +m g h
August 28, 2015

physics
Q = flow rate = speed * area 43 pi R^2 = n * .066 pi r^2
August 28, 2015

physics
delta p = rho g delta h 35*10^3 = 1025 *9.81 * h h = 3.48 meters
August 28, 2015

physics
hey, I did the one about the eardrums.
August 28, 2015

physics
k x = 250 = 510 x so x = 250/510
August 28, 2015

physics
power = work/time = F * d /t so 50.2 = F * 1.17 / 1.84 = 78.9 N agree
August 28, 2015

Physics
v = a t
August 28, 2015

  1. Pages:
  2. 1
  3. 2
  4. 3
  5. 4
  6. 5
  7. 6
  8. 7
  9. 8
  10. 9
  11. 10
  12. 11
  13. 12
  14. 13
  15. 14
  16. 15
  17. Next>>

Members