Friday
August 26, 2016

Posts by Damon

Total # Posts: 26,794

Energy of satellite PHYSICS
F = G m Me/(h+Re)^2 so let R = 2.3*10^7 + RE centripetal a = v^2/R so F = m a = m v^2/R = mG Me/R^2 or m v^2 = m G Me/R and .5 mv^2 = .5 m G Me/R
April 10, 2016

Geometry
Now do you know way the biggest rectangle area for 300 foot fence is a square? fence = 2 L + 2 w = 300 so L = 150 - w A = L W A = (150-w)w = 150 w - w^2 so w^2 -150 w = - A w^2 - 150 w + 75^2 = -A + 5625 vertex at w = 75 area = 5625
April 10, 2016

Geometry
fence length = 300 feet max is a square 300 = 4s s= 300/4 = 75 area = s^2 = 5625
April 10, 2016

Geometry
total area = (25+8)(12+8) water surface area = 25*12 = 300ft^2 subtract
April 10, 2016

PHYSICS CENTER OF MASS
.065 is the area of the plater with the hole removed
April 10, 2016

PHYSICS CENTER OF MASS
mass = 2.79(.23*.37-pi(.08)^2) = 2.79(.0851-.0201) = 2.79 * .065 = .181 kg agree moment in x (forget the 2.79 density) .065 x = .0851*.37/2 - .0201*.125 .065 x = .0157 - .0025 = .0125 x = .192 meter = 19.2 cm now do y of cm the same way
April 10, 2016

Question
New York is a State New York is a City New York is part of the Northeast region of the US
April 10, 2016

Physics projectile
constant = kinetic E + potential E = (1/2) m v^2 + m g h but v = Vi - g t so v^2 = Vi^2 - 2 Vi g t - g^2 t^2 so Ke = (1/2) m v^2 = .5m [ Vi^2 - 2 Vi g t - g^2 t^2] which is a parabola with vertex at (.5 m v^2) and dropping off with time
April 10, 2016

Statistics
http://davidmlane.com/hyperstat/z_table.html
April 10, 2016

Quick Physics help
the rope the earth it is disturbed In your book, still 20 meters In real life due to the nonlinear behavior of shallow water waves, it will experience a net drift toward shore. 25 bounces / 5 seconds = 5 Hz
April 10, 2016

Physics
u = 30 cos 60 = 15 m/s so x = 15 * 4 = 60 meters away if we are interested now vertical Vi = 30 sin 60 = 26 m/s how far up in 4 seconds? h = Vi t - 4.9 t^2 = 26(4) - 4.9(16) = 104 - 78.4 = 25.6 I get, wonder if you use 4.9 for 9.81/2
April 10, 2016

statistics
why not?
April 10, 2016

Physics
here: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan.html NOW, that is the power PER UNIT AREA so 3.9 *10^26 / (4 pi r^2) = power per unit area = constant*T^4 as shown in Stefan/ B link
April 10, 2016

PHYSICS ENERGY CONSERVATION!!
But, but, conservation is in your title !!!!
April 10, 2016

PHYSICS ENERGY CONSERVATION!!
at start E = (1/2) m v^2 + m g h E = (1/2)(395)(17.7)^2 + 395*9.81*7.2 = 61875 + 27900 = 89775 Joules at C 89775 = (1/2)395(7.6)^2+395*9.81*h h = [ 89775 - 11408] / (3875) h = 20.22 so agree but part b is trivial: 89775 is the total mechanical energy forever and ever by the ...
April 10, 2016

factoring polynomiald
8 b^2 + 6 b + 1 well 2+4 = 6 and 2*4 = 8 so (4b+1)(2b+1)
April 10, 2016

Math
L runs 3/5 mile/5 min = 3/25 mile/min 3 mile /3/25 mi/min = 25 min A runs7/10 / 5 = 7/50 mile/min 3 mile/ 7/50 = 150/7 = 21.4 min 25 - 21.4 = 3.6 min
April 10, 2016

Math
int (10t+1) dt = 5 t^2 + t at t = 0 that is 0 at t = x+3 that is 5(x+3)^2 +(x+3) subtract F(x) = - 5(x+3)^2 - x - 3 now do d/dx -10(x+3) - 1 or -10 x - 31
April 10, 2016

science
does pink have green?
April 10, 2016

No such thing as acceleration in m/s
-(20/3) m/s^2
April 10, 2016

math
draw the triangle
April 10, 2016

science
force = change of momentum/time = - m v /t force / area = force / given area by the way your units for first person's head area are wrong.
April 10, 2016

math
100 (80-60)/60
April 10, 2016

physical science
I guess net force includes gravity down so Force * time = change of momentum 6000 * 2.5 = 2000 (v-10)
April 10, 2016

Precalculus
AB = 6 AC = 8 all I need to know actually is AC = 8 so circumference = 8 (360/45) = 64 = 2 pi r r = 32/pi pi r^2 = pi (1024/pi^2) = 326 whatevers, miles, astronomical units, thumbs (I do physics not math)
April 9, 2016

algebra
20.5/11 = 2^n n log 2 = log 1.8636 n = .898 .898 * 6 hours = 5.39 hours
April 9, 2016

Science
F = k Q1 Q2/d^2 where k = 9 * 10^9 Q1 = Q2 = 1.6*10^-6 d = .028 meters = m g = 9.81 m
April 9, 2016

cool
Maybe there is an easier way, but that was fun !
April 9, 2016

math
log5 [ (3/5)(15^3/8) / (81/8)] well at least the 8 goes away easy log5 [ 3 *225 * 3 / 81 ] log5 [ 225/9 ] 2 log 5 (15/3) LOL !!! 2 log5 (5) 2 :)
April 9, 2016

Physics
first drop at top 0 = Vi - 9.81 t t = Vi/9.81 at top h = .55 = Vi t - 4.9 t^2 .55 = Vi^2/9.81 - 4.9(Vi^2/9.81^2) .55 = Vi^2/19.62 Vi = 3.28 m/s second drop at top .40 = Vi^2/19.62 Vi = 2.80 m/s a = (2.80 - 3.28)/time slowing down average Vi = (3.28+2.80)/2 = 3.04 m/s so time ...
April 9, 2016

math, science, hindi, english, sst
BM = MC = x which is half of BC angle AMB = T then angle AMC = 180 - T cos angle AMB = = cos T cos angle AMC = cos(180-T)=-cos T now law of cosines 4^2 = x^2 + 3^2 - 2(3x)cos T 8^2 = 3^2 + x^2 - 2(3x)(-cos T) 16 = x^2 + 9 - 6 x cos T 64 = x^2 + 9 + 6 x cos T...
April 9, 2016

no, compounded
if simple yearly interest intererst each year = .04 * 3000 = 120 120 * 10 = 1200 so 4200 would be correct BUT if compounded 3000(1.04)^10 = 3000*1.48 = 4440.73
April 9, 2016

math
times t hours and (t+2) hours) d1 = 50 t d2 = 40(t+2) 50 t = 10 + 40(t+2) 10 t = 90 t = 9
April 9, 2016

math
-2c/3 + 8 -30yz + 50 y
April 9, 2016

math
Plug and chug: numerator: f(2) = 4+3 = 7 g(7) = 3(7)- 2 = 19 f(19) = 38+3 = 41 denominator: g(2) = 6-2 = 4 f(4) = 8+3 = 11 f(11) = 22+3 = 25 so: 41/25
April 9, 2016

Graphing Ciricles
find the centers and radii x^2 - 10 x = -y^2 + 4 y +7 x^2 - 10 x + 25 = -y^2 + 4 y + 32 (x-5)^2 +y^2 -4 y + 4 = 36 (x-5)^2 + (y-4)^2 = 6^2 center at (5,4) r = 6 second one x^2 + 14 x +49 + y^2 + 6 y = 0 (x+7)^2 + y^2 + 6 y + 9 = 9 (x+7)^2 + (y+3)^2 = 3^2 center at (-7,-3), r...
April 9, 2016

Graphing Quadratics
zeros x = [-b +/- sqrt(b2-4ac)] /2a vertex therefore at x = -b/a 3 = -b/2a x intercepts are the same distance each side of 3 one is five to the left of 3 the other must be 5 to the right 3+5 = 8
April 9, 2016

Math
http://www.jiskha.com/display.cgi?id=1460217578
April 9, 2016

I just did this
check what I just answered.
April 9, 2016

wrong
(1+r)^t NOT (1+r)^2 except for two years 465,000 (1.06)^10 = 465,000 (1.79) = 832,744.18 now you do the rest
April 9, 2016

Math/Algebra
x = (3y-7)/(y+1) x + xy = 3y - 7 3 y - x y = x+7 y (3-x) = (x+7) y = -(x+7)/(x-3)
April 9, 2016

Statistics
http://davidmlane.com/hyperstat/z_table.html
April 9, 2016

Physics
You kidding ? 1/4 = 1/2 * 1/2 so two half lives :)
April 8, 2016

math
huh, just multiply 20 * 12 * 8
April 8, 2016

Physics
I thought I did :) surely you can google E = m c^2 (Albert Einstein) there E is in Joules which is watt seconds c is speed of light, about 3*10^8 meters/second an hour is 3600 seconds a kilowatt is 1000 watts which is 1000 Joules/second
April 8, 2016

Physics
E = m c^2 c^2 = (3*10^8)^2 = 9 * 10^16 E = 5 * 10^15 watts * 3600 seconds = 18 * 10^18 Joules m = 18*10^18/9*10^16 = 2 * 10^2 = 200 Kg about two big people mass :)
April 8, 2016

Physical Science
agree y = A sin (2 pi f t) so A is half the distance from sin = -1 to sin = +1 or from sin = 0 to sin = 1
April 8, 2016

check what I did
lots of algebra here here is the integral site: http://www.wolframalpha.com/calculators/integral-calculator/
April 8, 2016

Calculus
radius of cylinder of skin thickness dr (r goes from 0 to 1) r = 1-cos x dr = sin x dx so circumference = 2 π (1-cos x) height of that cylinderical shell = x dV = 2 π(1-cos x) x dr = 2 π (1-cos x)x sin x dx = 2 π x sin x dx - 2 π x sin x cos x dx = 2...
April 8, 2016

Science
Now wait a minute, of course it is A. Think about air warming and rising and new air coming inward underneath and air coming from the south going east fast with the earth but the earth moving slower under it as it goes north because we are getting closer to the axis of ...
April 8, 2016

Science Please help ASAP
And by the way their leader is presently deep in that cheap hot water.
April 8, 2016

Science Please help ASAP
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwiLx9md3f_LAhUGuxQKHTGJBuUQFggdMAA&url=http%3A%2F%2Fwww.theguardian.com%2Fenvironment%2F2008%2Fapr%2F22%2Frenewableenergy.alternativeenergy&usg=AFQjCNGuFFUv-l9dyXKYEDO1C2X-ku39nA&sig2=FM7A-...
April 8, 2016

Science Please help ASAP
You are welcome, and in Iceland they do not have to heat their hot water, just drill :)
April 8, 2016

Science Please help ASAP
Yes
April 8, 2016

Science Please help ASAP
Iceland :)
April 8, 2016

simultaneous equation
x^2+2xy-8y^2=0 (x+4y)(x-2y) = 0 so two routes to follow x = 2 y and x = -4y now the first one with x = 2 y 4 y^2 + y^2 - 4 y^2 = 21 y = +21 or - 21 then x = 42 or -42 so (42,21) (-42,-21) now the first one with x = -4y I will leave that for you
April 8, 2016

physics- help me please
pressure is weight per unit area the area at the bottom of the glass does not change however the mass of Hg is 13 times as much as that or the water therefore the pressure will be 13 times as big as P Hey, imagine the experiment !
April 8, 2016

physics- help me please
please look up the density of each. copper lead uranium then multiply by volume copper mass = copper density * 4 lead mass = lead density * 4 uranium mass = uranium density* 2 then list them in order
April 8, 2016

PE
You are welcome.
April 8, 2016

PE
http://www.jiskha.com/display.cgi?id=1460138784#1460138784.1460140028
April 8, 2016

PE
Look down to where I answered this.
April 8, 2016

PE
been there, did that scroll down
April 8, 2016

Math
Yikes, I did this a few minutes ago as well. 2
April 8, 2016

Math
How on earth would a bunch of retired teachers have the slightest idea what book you have or even what country you live in ?
April 8, 2016

Math
OIC
April 8, 2016

Math
The school? No way !!!
April 8, 2016

Math
v = pi r^2 h = pi (16)8 = 402 in^3 just two is 804 in^3
April 8, 2016

P.E.
2. disagree - http://www.google.com/search?q=central+nervous+system+components&ie=utf-8&oe=utf-8 3. agree 4. agree 5. agree
April 8, 2016

c = 100 + 2 n
Just in case you gave up :)
April 8, 2016

ATTENTION TEACHERS AND STUDENTS
c = f + n v or cost = fixed + variable * number that is a straight line with slope v and c intercept f 1100 = f + (500) v 1400 = f + (650) v --subtract---- ------------------- -300 = -150 v v = 2 then 100 = f so c = 100 + 2 n if n = 1000 c = 100 + 2000 = 2100
April 8, 2016

Elementary education
inside radius = 1 inch outside radius = 1.0625 inch volume = 1.25 (pi)(1.0625^2-1) = .5062 in^3 mass = 6 * .5062 = 3.04 oz
April 8, 2016

Science
.75 * 2.5 * 166
April 8, 2016

Math
vol of half sphere = (1/2)(4/3)pi r^3 vol of cone = (1/3)(5)(pi r^2) where r = 1.5
April 8, 2016

Algebra 1-HELP!
if x = 4 y = 6(4) - 1 y = 24 - 1 y = 23
April 8, 2016

Math
Yes, you are correct
April 8, 2016

algebra
(x^2-1) ------- (x+1) (x+1)(x-1) ----------- (x+1) = x-1
April 8, 2016

Physics
Oh all right I will do one more before getting grandkids up for school. dr/dt = (3.2+3.6t)i + (1.7-4.8t)j d^2r/dt^2 = 3.6 i - 4.8 j which is the acceleration, so what else is new? |a| = sqrt(3.6^2 + 4.8^2) tan angle north of east = -4.8/3.6 so angle South of East = 53.1 deg
April 8, 2016

Physics
oh well original velocity = 2.1 i + 0 j final velocity = Vx i + Vy j sqrt (Vx^2 + Vy^2) = 6.3 so Vx^2 + Vy^2 = 39.7 (Vx - 2.1)/3 = Ax (Vy - 0)/3 = Ay so Ay = Vy/3 Ax^2 + Ay^2 = 1.4^2 = 1.96 so three equations Ax^2 + Vy^2/9 = 1.96 Vx^2+Vy^2 = 39.7 Ax = (Vx - 2.1)/3
April 8, 2016

chemistry
4 mols HCl = 4 * (1+35.5) = 146 grams of HCl per liter so either mix a liter that way and pour out .2 liter or put .2*146 = 29.2 grams of HCl in .2 liter of water Of course that is easier said than done because how do you get 29.2 grams of the acid HCl ? It is not a solid that...
April 8, 2016

Physics
how long do you take? 90 = 8 t t = 11.25 seconds 8 = 1.20 v v = 6.67 m/s so 90 = 6.67 t t = 13.5 s so you should start 13.50 - 11.25 = 2.25 seconds after him
April 8, 2016

Physics
you went 15/60 * 13 = 3.25 miles in first 13 min so 26 - 3.25 = 22.75 miles left and 34 - 13 = 21 minutes left which is 21/60 = .35 hours so 22.75 miles/.35 hours = 65 mph
April 8, 2016

math
+ 24 * 20 = 2 * 240 = 480
April 8, 2016

sorry, multiply by g
need weight/area, not mass /area 600 * 9.81 = 5886 Pascals
April 8, 2016

science
That little piece of wood does NOT weigh 900 kg (maybe your car does) I think you mean 0.900 kg or 900 grams make its contact with the table as small as possible while not tipping over (standing on end) so area touching table is .05 * .03 = .0015 m^2 so p = force/area = 0.9/....
April 8, 2016

Physics
h = 40.2 + Vi t - 4.9 t^2 at ground h = 0 4.9 t^2 - Vi t - 40.2 = 0 but t = 4 so solve for Vi
April 8, 2016

physics
x = sin (2pi*741t) y = sin (2pi*715t) x+y= sin (2pi*741t)+sin(2pi*715t) but sin a + sin b= 2 sin.5(a+b)cos.5(a-b) so x+y =2 [sin average] cos half difference every max of the cosine, either + or - is a big noise so what you hear if they are close is the average frequency times...
April 8, 2016

physics
you hear the difference frequency 8 = 3580 - f f = 3472 original 12 = 3580 -f f = 3568 final good, the frequency went down when I loosened the string so 3568 Hz WHAT if I wrote the difference the other way (all I know is the absolute value) 8 = f - 3580 f = 3588 12 = f - 3580 ...
April 8, 2016

Physics
4.8 = u t what is t, the time airborne? 2 = 4.9 t^2 so t = sqrt(.408) = .639 second so u = 4.8/.639 = 7.51 m/s
April 8, 2016

maths help me urgently!!!!!!
i^2 = -1 1 - 2(-1) = 3 so this is 3/i multiply top and bottom by i 3 i/-1 or -3i
April 7, 2016

physics
omega = w = 2 pi f = sqrt(k/m) w = sqrt (222/.58) = 19.56 radians/sso x = .0335 sin 19.56 t v = .0335(19.56) cos 19.56 t a = -.0335(19.56)^2 sin 19.56 t = -19.56^2 x max v when cos 19.56 t = 1 and x = 0 so all energy is kinetic max v = .655 m/s (1/2) m v^2 = .125 J agree with ...
April 7, 2016

Physics
Initial momentum 390*20 - 500*8 = 3800 , x direction Final momentum = (390 + 500)v = 890 v , x direction But we all know from the first law deduced by Isaac Newton that since there are no external forces on this system in the x direction there will be no change in x momentum. ...
April 7, 2016

Physics
22*13.8 - 188 v = 0 v = 1.61 m/s
April 7, 2016

maths
23/3 = 7 2/3 so 8
April 7, 2016

maths
one man takes (6hr/7holes)5 men = 30/7 man hr per hole so 15/7 for half a hole
April 7, 2016

maths
I needed a common multiple of 2 and 3 that is 6 we are not doing fractions here, just integers
April 7, 2016

maths
a b c d d = 2 a b = 2 c a+d = 2 c ---------------------- a = 2 c - d = 2 c - 2 a so 3 a = 2 c hmmmm if c is 1, nope need common multiple for integer like 3 a = 6 2 c = 6 looks like a = 2 and c = 3 so far: 2 b 3 d but d = 2 a 2 b 3 4 b = 2 c so 2 6 3 4 2634
April 7, 2016

calculus
v = 5 t^-.5 = 5/sqrt(t) a = dv/dt = -2.5 t^-2.5 x = (5/.5)t^.5+c = 10 t^.5 + c 11 = 10 (1)^.5 + c c = 1 so x = 10 sqrt(t) + 1
April 7, 2016

calculus
a = -9.8 v = Vi - 9.8 t h = Hi + Vi t +(1/2) a t^2 h = 2300 + 0 t - 4.9 t^2 = 2300 - 4.9 t^2
April 7, 2016

calculus
v = vi - a t 0 = 7 - 9.8 t t = 7/9.8 at top when v = 0 h = 3 + 7 t - 4.9 t^2
April 7, 2016

physics
frequency proportional to sqrt(g/L) g proportional to mass of planet and 1/r^2 g planet = g earth * 1.75/6.25 = .28 sqrt gplanet = sqrt gearth =.529 so frequency is .529 tht on earth period = 1/f so 1.6/.529 = 3.02 seconds
April 7, 2016

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