Wednesday
October 1, 2014

Posts by Damon


Total # Posts: 18,728

physics
here http://en.wikipedia.org/wiki/Geostationary_orbit 35,786 kilometers above earth
September 30, 2014

physics
look up geostationary satellite
September 30, 2014

physics
F = m v^2/r
September 30, 2014

Algebra
Yes.
September 30, 2014

Algebra
(-7,3) I think I do not do interval notation either.
September 30, 2014

Algebra
(x+2) < 5 and -(x+2) <5 x < 3 and (x+2) > -5 x < 3 and x > -7 which is -7 < x < 3
September 30, 2014

Physics-Intro
good grief, I have not seen those units for a while still F = m a force and weight in pounds, mass in slugs acceleration in ft/s^2 F = 25,000 * 28 = 700,000 pounds
September 30, 2014

physics
.424 * 10^8 m/s = 4.24 * 10^7 or a bit over a tenth of the speed of light.
September 30, 2014

Algebra 2 Answer Check
2 y = -5 x + 8 y = -(5/2) x + 4 slope = -5/2 so slope of perpendicular = 2/5 y = -(2/5) x + b 3 = -(2/5)5 + b 3 = -2 + b b = 5 y = -(2/5) x + 5
September 30, 2014

Algebra 1
1 a try x = -1 1 </= -1 nope b x = -1 works but x = 10 fails totally c x^2 </= 23.25 x^2 x^2 always + so this works by the way d is 4 x^2 -24 x + 36 >/= 4 x^2 - 3 -24 x + 39 >/= 0 nope
September 30, 2014

Typo
If you are really serious about only 11 meters^2 then (w+6)w = 11 w^2 + 6 w - 11 = 0
September 30, 2014

Physics
F = m a Ft = tug force = - Fa asteroid force 3360 vt + 6300 va = 0 momentum remains 0 490 = 3360 at -490 = 6300 aa at = .146 m/s^2 aa = -0.778 m/s^2 vt = 0 + .146 t va = 0 - .778 t position t = .5 (.146)t^2 430 - position a = .5 (-.778)t^2 they are headed toward each other so ...
September 30, 2014

Trigonometry
if theta is between 0 and -90 (quadrant 4) the sin is negative. Therefore we only look at quadrant one. sin^-1 0.95 = 71.8 degrees
September 30, 2014

chemistry
first balance 2 NaClO + H2O --> 2 Na+ +2OH- + Cl2 + O2 How many mols of NaClO ? Na = 23 g/mol Cl = 35.5 O = +16 so NaClO = 74.5 g/mol 2 NaClO = 149 g then grams of NaClO = .0585 *1.12*15 = .983 grams of NaCl .983/74.5 = .0132 mols of NaClO we get half as many mols of O2 so ...
September 30, 2014

Algebra
L = w + 4 L w = 165 (w+4)w = 165 w^2 + 4 w - 165 = 0 (w+15)(w-11) = 0 w = 11
September 30, 2014

Physics
phase 1 v = 5 t , slope up of 5 up to Vi = 25 phase 2 v = constant = 25 from t = 5 to t = 20 phase 3 v = 25- 5(t-20), slope down of -5
September 30, 2014

Pre-Calculus/Trigonometry
You are welcome :)
September 30, 2014

Pre-Calculus/Trigonometry
would it be like this for a, and if so how would i continue that? (f o g)(x)= 1/[(f o g)(x)-5]? ======================= no, just do what it says f (g(x)) use g(x) = (x^2+2) for argument of f in other words f (x^2+2) = 1/[ (x^2+2) - 5 ]
September 30, 2014

Pre-Calculus/Trigonometry
replace x by x^2+2 1/[ (x^2+2) -5 ] = 1/(x^2 - 3) b. f(6) = 1/1 = 1 g(1) = 1+2 = 3
September 30, 2014

precal
9 9r 9r^2 9r^3 -72 = 9 r^3 r^3 = -72/9 now work back a9 = 9/r a8 = 9/r^2 a7 = 9/r^3 interesting a7 = 9/r^3 = (9)(-9/72) = -81/72
September 30, 2014

physics
I could swear I did this one yesterday :( ball 1 d = distance down d = .5 g (t+1)^2 ball 2 d = 40 t + .5 g t^2 so .5 g (t^2 + 2 t + 1) = 40 t + .5 g t^2 put in whatever you use for g (9.81, 9.8 or 10) and solve the quadratic
September 30, 2014

ALgebra 2
From 0 go left 1/2 then go left another 3/4 see that you are now at -1 1/4
September 30, 2014

ALgebra 2
-2/4 - 3/4 = -5/4 = -1 1/4 Sketch this on a number line !!!!
September 30, 2014

mathematic
p = r - c p = 150 n - 850 - 76 n p=74n-850
September 30, 2014

math exponential function
450 (1.06)^(2n) = 477 1.06^2n = 1.06 n = 1/2 year
September 30, 2014

Calculus
ln y = x ln 2 1/y dy/dx = ln 2 dy/dx = y ln 2 or dy/dx = 2^x ln 2
September 28, 2014

physics
time for first rock -20 = -5 t^2 t = 2 seconds to fall so t for second ball = 2 - 1 = 1 second -20 = -Vi t + -5 t^2 20 = -Vi + 5 Vi = -15 m/s (the - sign means speed is down)
September 28, 2014

physics
Da = Db same distance total time a = time b + delay b we want time b Car A accelerate phase: vi = aA delayb Di = .5 aA delayb^2 constant speed phase Da = Di + vi t = .5 aA delayb^2 + aA delayb timeb Car B Db = .5 aB timeb^2 now Da=Db so .5 aA delayb^2 + aA delayb timeb = .5 aB...
September 28, 2014

physic
first vertical problem 45 = 4.9 t^2 t = 3.03 seconds to fall distance ball is from building = 3.03*5 = 15.15 distance man must run = 15.15 - 6 = 9.15 time man has = 3.03-.3 = 2.73 seconds 9.15 = .5 a (2.73)^2 solve for a
September 28, 2014

trigo
cos 3 x = 4 cos^3 x - 3 cos x
September 28, 2014

SCIENCE - PLEASE HELP PLESE
4) Multiply 4.135 x 4.688 888 887 m x 8.7m round your answer to the correct number of significant figures. ============================ You only have 2 sig figs because you said 8.7 not 8.70000000 so 19.388555555 is 19 <-------answer
September 28, 2014

SCIENCE - PLEASE HELP PLESE
3) Round 3155.24m, 8.777 73 cm, and 93.775 57 kg to one less significant figure than they each have currently. ==================== 3155.24 4 is less than 5 so 3155.3 3<5 so 8.7777 93.77557 7>5 so 93.7756
September 28, 2014

SCIENCE - PLEASE HELP PLESE
2) Find the weight of a 12.25 kg dog. Round your answer to the correct number of significant figures. Use weight=massxfree-fall acceleration. g is different in different places on earth. We need it to four significant figures because your mass is to four sig figs. I will call ...
September 28, 2014

SCIENCE - PLEASE HELP PLESE
1) Round 578.683 m, 47.3333 kg, and 789.5 cm to four significant figures. 0,1,2,3,4 round down 5,6,7,8,9 round up 578.6 83 8 is greater than 4 so this becomes 578.7 meters 47.33 33 3 is less than 4 so this becomes 47.33 kilograms 789.5 cm This already has four significant ...
September 28, 2014

trigo
h = L (1-cos T) geometry exact cos 2A = 1 - 2 sin^2 A identity so cos T = 1 - 2 sin^2 (T/2) h = L [ 1 - (1 -2 sin^2 (T/2) ] = L [2 sin^2 (T/2) ] = 20 sin^2 (T/2)
September 28, 2014

physics
2.4*84
September 28, 2014

physics
84*.24
September 28, 2014

geometry
height = h = 280/40 V = (1/3)(40)(h) the volume of any pointy thing with straight sides = (1/3) base area * height
September 28, 2014

math
in the ten based number system: To multiply by ten, add a zero To divide by ten, move decimal point one space left 200 / 10 = 20.0 = 20
September 27, 2014

physcis
.926 = (1/2)(9.8) t^2 solve for t u = 18.3/t
September 27, 2014

physics
r = 33*10^6 + 6.37*10^6 2 pi r = circumference of orbit v = 2 pi r/(24 h * 3600 s/h) Ac = v^2/r
September 27, 2014

physics
1.1 = Vi t - 4.9 t^2 t = 4.4/u but u = Vi because tan 45 = 1 1.1 = u t - 4.9 t^2 1.1 = u t - 4.9 (4.4^2)/u^2 1.1 u^2 = u^2 (4.4) - 94.9 3.3 u^2 = 94.9 u = Vi = 5.36 m/s sqrt(u^2+Vi^2) = 7.58 m/s
September 27, 2014

physics
45 F = 30*(45-15)
September 27, 2014

physics
200*10^3 = .2*10^6 m high R earth = 6.38*10^6 so R = 6.58 * 10^6 meters G = 6.67384 × 10-11 m3 kg-1 s-2 earth mass = Me = 5.97*10^24 kg m v^2/R = G Me m /R^2 v^2 = G Me/R = 6.67 * 5.97 /6.58 * 10^(-11+24-6) = 6.05 * 10^7 = 60.5 * 10^6 so v = 7.78*10^3 = 7,780 m/s (PART B...
September 27, 2014

physics
a = change in velocity / change in time = -16.7 / t t = distance/ average speed = .67/8.35 = .0802 second so a = -16.7 / .0802 = -208 agree F = m a = 42 * -208 = -8736 Newtons AGREE
September 27, 2014

Math
Try the rest now.
September 27, 2014

Math
10 balls at start 1 prob black, white, red = 3/10 * 4/9 * 5/8 2 prob black, red, white = 3/10 * 5/9 * 4/8 same as above 3 prob white, black, red = 4/10 * 3/9 * 5/8 same again 4 prob white, red , black same 5 prob red , white, black same 6 prob red, black, white same so 6 * 3/...
September 27, 2014

Engineering science
fresh water is about 1 kg/Liter so m g h/t = 9000 kg * 9.81 * 70/3600 seconds = 1717 Watts done = 1717 Joules/second * 3600 seconds/hr = 6,180,300 Joules/hour = 1717Joules/second*60 s/min = 103,020 Joules/min
September 27, 2014

science
3000*1 = F = 4000 * x x = .75 m/s^2
September 27, 2014

chemistry
. 4 mol/liter = .0004 mol/mL 30 * .0004 = 0.012 mol NaOH .012 mol NaOH in 100 mL is .12 mol/liter
September 27, 2014

physics
Gravitational force = G mplanet m/d^2 G = 6.67384 × 10-11 m3 kg-1 s-2 so FB = 6.67384 × 10-11 m3 kg-1 s-2 MB*6930/(3.01*10^6)^2
September 27, 2014

physics
FB = G MB 6930/(9*10^12) FA = G MA 6930/(9*10^12) MA = (9*10^12/6930 G) FA MB = (9*10^12/6930 G) FB ---------------------------- MA - MB = (9*10^12/6930 G)(FA-FB)
September 27, 2014

chemistry
100 (4.78/6.67)
September 27, 2014

math
multiply first equation by 6 6 x + 30 y = 36 6 x - 15 y = 18 --------------- subtract 45 y = 18 y = 18/45 = 6/15 x = 6 - 5 y x = 6 - 2 x = 4
September 27, 2014

chemistry
check, yes they add to 100 well, let's say we have 100 grams of this stuff Then we have 62.04 grams of C 62.04 / 12 = 5.17 mols of C 10.41 mols of H 27.55/16 = 1.72 mols of O 10.41/5.17 = 2.01 so 2 H for every C 10.41/1.72 = 6.05 so 6 H for every O 3C 6H 1O or C3H6O which ...
September 27, 2014

Physics
2 pi radians is a revolution so 8 pi radians is four revolutions
September 27, 2014

Algebra 2
one out of 50 bears caught is tagged so 50 * 50
September 27, 2014

math
distance flown = 16/cos 60 = 32 km 32 km/(1/60)hr = 60 * 32 = 1920 km/hr
September 27, 2014

chemistry
mol of NO2 mass = 14+32 = 46 grams/mol mol of N = 14 100 * 14/46 = 30.4%
September 27, 2014

Algebra 2
There must be more to this problem than just (y-1)/(x+3) = -3/4 That is the equation of a straight line 4 y - 4 = -3 x - 9 4 y = -3 x - 5 y = -(3/4)x - 5/4
September 27, 2014

math
a60 = a1 + (59)(7) a60 = -15 + 413 = 398 S60 = 60 (-15 + 398) / 2 =11490
September 27, 2014

Math one question?
350 +225 ----- =575
September 27, 2014

physics
power stage v = Vi + a t v = 0 + 25 * 3.77 v = 94.25 m/s when fuel runs out h = 0 + 0 t + (1/2)(25)(3.77)^2 h = 177.7 meters high when fuel runs out Coasting stage, Hi = 177.7 meters and Vi = 94.25 m/s then at top v = 0 0 = 94.25 - 9.81 t t = 9.61 seconds coasting up h = Hi + ...
September 26, 2014

Pre-Calc
(f+g)(x) = x + x + 2 - 2 = 2 x do the others the same way
September 26, 2014

Science-HELP?
at least it works until the sea rises a little :(
September 26, 2014

Science-HELP?
sure, that works
September 26, 2014

physics
I answered that. http://www.jiskha.com/display.cgi?id=1411686019
September 25, 2014

Physics
Horizontal F = m v^2/r Vertical Fmax = m g + mv^2/r m g + m v^2/r = 1.16 m v^2/r g = .16 v^2/r .16 v^2 = 9.8(.7) solve
September 25, 2014

Match
162 + 284 is something like 140 + 300 which is 440 you don't need 98 to get to 500 from there
September 25, 2014

Math
http://davidmlane.com/hyperstat/z_table.html
September 25, 2014

Algebra 1
.91 = sum of first 6/6 so sum of first 6 =5.46 sum of first seven then is 5.46 + x so (5.46 + x)/7 >/= .92 5.46 + x >/= 6.44 so x >/= .98
September 25, 2014

Algebra 1
you can not just say less than 90 because you must include 90 therefore less than OR EQUAL TO 90
September 25, 2014

Algebra 1
Because It could be EXACTLY 80 or EXACTLY 90
September 25, 2014

Algebra 1
top will get 90 bottom will get 80 so what do you think?
September 25, 2014

math...
looks good to me.
September 25, 2014

physics
acceleration = change in velocity / change in time = (35 - 65) / 4.2
September 25, 2014

Physics
a = -9.81/4 = -2.45 m/s^2 0 = 6 - 2.45 t t = 2.45 seconds d = Vi t + (1/2) a t^2 d = 6 (2.45) - 1.23 (2.45^2) d = 7.31 meters
September 25, 2014

Physics
m v1^2/r = (9) m v2^2/r v2^2/v1^2 = 1/9 v2/v1 = 1/3
September 25, 2014

math
2. y + 2y + 3z combine like terms y + 2 y = 3 y so 3 y + 3 z B. 3y + 3z =================== Hey, you got the first one right. This is really no different 3. 6r + r - 5r (6+1-5)r = 2r A. 2r ========================= 4. 5x + 2(x + 6) is 5 x + 2 x + 12 or 7 x + 12 C. 7x + 12...
September 25, 2014

Physics
v1^2/r1 = v2^2/r2 v1^2/v2^2 = r1/r2 v1/v2 = sqrt (r1/r2)
September 25, 2014

Physics
weight = k r^3 drag = c r^2 v^2 at terminal speed, drag/weight = 1 drag/weight = const v^2/r so V1^2/R1 = V2^2/R2 V2^2/V1^2 = R2/R1 V2/V1 = sqrt (R2/R1)
September 25, 2014

Algebra
[(-3 x + 2 )(-2) -14 ]/6 [(6 x - 4 ) -14 ]/6 [6 x -18 ]/6 x - 3 write it down add three and you get x back :)
September 25, 2014

Calculus
f(x+h) = (x+h)^2 + x + h = x^2 + 2 h x + h^2 + x + h f(x) = x^2 + x slope = [f(x+h) - f(x) ]/h = [ 2 h x + h^2 + h ]/h = 2 x + h + 1 now at the point x = -1, h --->0 and slope = 2 x + 1 which is -2 + 1 = -1 so form of tangent is y = -1 x + b now what is y at x = -1 y = (-1...
September 25, 2014

Physics
assuming the current is perpendicular to the swimmer heading, it has nothing to do with the problem. It just means she will land somewhere downstream of the starting point. distance = speed * time = 0.4 * 200
September 25, 2014

Math
0.0034 move decimal point two places to the left to divide by 100 in ten based number system.
September 25, 2014

physics
dv = 4 pi r^2 dr note(surface area * dr) dv/v = 4 pi r^2 dr / (4/3) pi r^3 =3 dr/r
September 25, 2014

physics see question above
been there, done that
September 25, 2014

Physics
first drop the ball to see how long it is in the air 7.5 = 4.9 t^2 solve for t now horizontal problem u t = 9.5 u = 9.5 / t
September 25, 2014

physics
a + g = 7 + 9.8 = 16.8 m/s^2 F = 15 (16.8) = 252 N , bag tears
September 25, 2014

physic
F = k Q1 Q2 / d^2 where k = 9 * 10^9
September 24, 2014

physics
a = - 9.8 m/s^2 v = Vi + a t = 0 - 9.8 t h = Hi + Vi t -(9.8/2) t^2 0 = Hi + 0 (3) - (9.8/2)(3)^2 4.9 (9) = Hi Hi = 44.1 meters high
September 24, 2014

History on Middle Ages(PLEASE HELP NOW)
They had religious issues? I thought those were pre-decided in Rome :)
September 24, 2014

Math
well, surely x = -5 then y = 4
September 24, 2014

statistics
mean = 2.34 sd = .2 z = + or - .03/.2 look for probability of being within z = +/- .15 of mean
September 24, 2014

statistics
http://davidmlane.com/hyperstat/z_table.html
September 24, 2014

Physics MCAT, Help please
original momentum = 6 * 4 = 24 final momentum = 2 * 8 + V * 4 16 + 4 v = 24 4 v = 8 v = 2 m/s
September 24, 2014

Math
all components the same x i + x j + x k d = sqrt (3 x^2 ) = x sqrt 3 so if d = 1 x = sqrt(3) /3 so (sqrt 3/3)(i + j + k)
September 23, 2014

Science
(-4+8)/2 = 2
September 23, 2014

Physics
x = Xi + Vi t + (1/2) a t^2 4200 = 0 + 7.2 t + (1/2) a t^2 but t = 4 * 60 = 240 seconds so 4200 = 7.2(240) + .5 a (240)^2 solve for a then v = Vi + a t v = 7.2 + a (240)
September 23, 2014

math
(.2)gal/.08 shed = 2.5 gal /shed 2.5 gal/shed * 4 sheds = 10 gallons
September 23, 2014

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