Sunday
August 28, 2016

Posts by Damon

Total # Posts: 26,833

maths
90/90 - 28/90 = 62/90 = 31/45
February 7, 2016

physics (mechanics)
a = (20-15)/10 = 0.5 m/s^2 F = m a F = 1000 (0.5) + 270 F = 500 + 270 F = 770 N
February 7, 2016

math
combined speed = 110 110 mi/h * t = 660 t = 6 yes
February 6, 2016

Math
d = 4 q 10 d + 25 q = 390 10 (4q) + 25 q = 390 65 q = 390 q = 6 etc Your error is here: 0.40q+0.25q=3.90 then you said 65q=3.90 no 0.65 g = 3.90 3.90/0.65 = 6 not .06
February 6, 2016

pysics
Q = C m (T2-T1) = 400 (.5 kg) (116-16) note difference in deg K is the same as difference in deg C = 20,000 Joules
February 6, 2016

Math
34.375 / .125 = 275 I divided I do it the science way, multiply so units cancel you can do it by ratios .125 in/1 ft = 34.375 in / x ft .125 x = 34.375 x = 34.375 / .125
February 6, 2016

Math
34.375 in (1 ft/.125 in) = 275 ft
February 6, 2016

Math
That name game is just part of trying to hopelessly confuse me.
February 6, 2016

Math
LOL, talk about trying to confuse me ! If those are corresponding sides in two triangles and A is 4 times X then B is 4 times Y and m = 10/4 = 2.5 and C is 4 times Z and n = 16/4 = 4
February 6, 2016

Math
not without knowing the angles
February 6, 2016

Physics 30
Hey, just use Coulomb's Law F = k Q1 Q2 / d^2 if like charges, repel if opposite signs, attract see: http://en.wikipedia.org/wiki/Coulomb's_law
February 6, 2016

physics & math
sqrt ( 2*1.6*10) = 4 sqrt 2 = 5.66 m/s
February 6, 2016

typos
You mean g = - 32 ft/s^2 so h = Hi + Vi t + (1/2)a t^2 h = 105 - 9 t - 16 t^2 at ground: 0 = 105 - 9 t - 16 t^2 or 16 t^2 + 9 t - 105 = 0 t = [ -9 +/- sqrt(81+6720)]/32 t = [-9 +/- 82.5 ]/32 use positive time 2.30 seconds
February 5, 2016

Physics
V= i R 2 = .1 R and 2 = 5 R
February 4, 2016

Physics help
well electrostatic force causes hair to stand on end and gravity keeps the planets in orbit by the way
February 4, 2016

Physics PLEASE PLEASE HELP! CONFUSED
do vertical and horizontal problems separately Vertical Just plain fall, no initial velocity up or down so a) 10 = (1/2)(9.81) t^2 b) use that t to find out how far away he landed d = u t = 1.2 t c) vertical v = g t = 9.81 t horizontal u = 1.2 speed = sqrt (u^2+v^2) direction ...
February 3, 2016

physics
again that d is the part in the heavy liquid for the water depth use L-d
February 3, 2016

physics
B) rhoL L^2 d + rhoW L^2 (L-d) = rhoB L^3
February 3, 2016

physics
Force up on block = rhoL *L * L * d * g where d is the draft or distance submerged that has to equal the weight of the block which is rhoB L^3 g so rhoB L^3 g = rhoL L^2 d g d = (rhoB/rhoL) L d/L = rhoB/rhoL but we want (L-d)/L which is 1 - d/L 1 - d/L = fraction above = 1-...
February 3, 2016

True & False explanations Physics
When a projectile is fired at 45 deg. angle and is in free fall, the only point along the path that the acceleration of the object is zero is the instant when the object is at the highest point of its path. Answer: False Can someone explain how? ============================== ...
February 3, 2016

physics
v = Vi - g t v = 20 - 9.81(2) h = Vi t - 4.9 t^2 h = 20(2) - 4.9 (4)
February 3, 2016

One Last Queston
My vote is for A Nothing slows it down
February 2, 2016

differential equations
for purposes of integration n k m are constant then ds/dt = -ks (s^2/nm - S/n -s/m +1) = -k [ s^3/nm - s^2/n - s^2/m + s] =k[ -s^4/4nm +s^3/3n + s^3/3m -s^2/2 + c] You can play with this perhaps http://www.wolframalpha.com/input/?lk=3&i=plot++-s^4%2F4n+%2Bs^3%2F3n+%2B+s^3%2F3...
February 2, 2016

Physics
so weight = 4.11*9.81 = 40.3 N down Tension = 23.5 N up 23.5 - 40.3 = 4.11 a a = - 4.09 m/s^2 so a is down, weight wins
February 2, 2016

but what about the weight?
weight = m g = 4.11 * 9.81 Newtons
February 2, 2016

Math
V = pi r^2 h
February 2, 2016

maths
5/35 = x/21 x = 21 * 5 / 35
February 2, 2016

Algebra
I think you have typos but perhaps .75 x = 30
February 2, 2016

Algebra
in pennies: 4500 + 29.5 m = 9000 + 7 m 22.5 m = 4500 m = 200 miles
February 2, 2016

math
approximately 40828.19332
February 2, 2016

Math
56 * 4 = 224
February 2, 2016

US History
LOL - that was a media generated war ! It was the very origin of the term: "yellow journalism" starting with the explosion of the Battle ship Maine which seems to have been an engineering error but the press blamed on the Spanish. See: http://history.state.gov/...
February 2, 2016

Which war ?
Civil war? Vietnam ? Iraq?
February 2, 2016

algebra
100 a + 75 s = 14000 pennies a+s = 150 so a = 150-s 100(150 - s) + 75 s = 14000 15000 - 25 s = 14000 1000 = 25 s s = 40 then a = 150 - 40 = 110
February 2, 2016

algebra
2 x + 3 y = 252 4 x + 1 y = 244 multiply second equation by 3 2 x + 3 y = 252 12x + 3 y = 732 -----------------subtract - 10 x = - 480 x = 48 then y = 244-192 = 52
February 2, 2016

algebra
number = 10 x + y x+y = 12 y = 2 x so x + 2 x = 12 x = 4 then y = 8 so 48
February 2, 2016

algebra
f+4 = 3 (s+4) f-6 = 7(s-6)
February 2, 2016

math Chem formula wrong
3 % C 10 % Ca 87 % O Like no way CaCO3 40 + 12 + 48 = 100 molar mass 40% Ca, 12% C , 48% O so the real answer is 400 g , 120 g 480 g BUT using your strange numbers: in 100 grams: .03 * 100 = 3 g .1 * 100 = 10 g .87 * 100 = 87 g
February 2, 2016

Math
That is high precision. For low I would pick 3*10^3
February 1, 2016

Science
I guess they stick together. 8*10 - 6*50 = (6+8) v -220 = 14 v v = -15.7 m/s
February 1, 2016

Math
F = k x 10 = k (.5) k = 20 lb/in 15 = 20 x x = 0.75 in
January 31, 2016

mathematics
(6^5 /6^3) + 7^0 ??? 6^2 + 1 37
January 31, 2016

science
50 v = .1(50) v = .1 m/s
January 31, 2016

Science
Those are VECTORS You need BOTH magnitude and direction to add them. The resultant could have any magnitude between 20 and 70 meters
January 31, 2016

Science
r and Re F = G Mm/r^2 = (.25) G Mm/Re^2 or .25/Re^2 =1/r^2 .25 r^2 = Re^2 .5 r = Re r = 2 Re height = 2Re-Re = Re
January 31, 2016

physics
h = Hi + Vi t - 4.9 t^2 0 = 29 - 8.95 t - 4.9 t^2 t = [8.95+/-sqrt(8.95^2 + 4*29*4.9)]/(2*4.9) t = [8.95 +/-25.46 ] /9.81 use + t 3.51 seconds
January 31, 2016

physics
v = 19 - 9.81 t at top v = 0 t = 19/9.81 = 1.94 seconds to top at top h = 0 + 19 t - 4.9 t^2 h = 18.4 m high at top the same as the rise time 1.94 s the same 19 m/s but down now
January 31, 2016

physics
v = 0 = 81 - 5 t 800 = 81 t - 5.2 t^2 use that same stopping time t
January 31, 2016

physics
I guess we are to do this all in feet and seconds? v = 205 mi/h *5280ft/mi*(1h/3600s)) = 301 ft/s a = 301/2.7 = 111 ft/s^2 d = (1/2)(111)(2.7)^2 =406 ft
January 31, 2016

Physics
9.7*3 + 7.6*0 = 9.7 Va + 7.6 Vb so Va = (29.1 -7.6Vb)/9.7 then .5(9.7)(9)= .5(9.7)Va^2+.5(7.6)Vb^2
January 31, 2016

Physics
if acceleration is constant their average speed during the stop = 10/2 = 5 m/s 5 m/s * 30 s = 150 meters
January 30, 2016

math
21/x = 7/10 ? multiply both sides by 10 x 21 * (10 * x)/x = 7 * (10 * x)/10 210 = 7 x x = 210/7
January 30, 2016

science
yes
January 30, 2016

Science
Yes, the answer is c
January 30, 2016

Math
2 y + 6 + 4 y =
January 29, 2016

MATHS
x + (5x-7) = 59 6x = 66 x = 11 and 5x - 7 = 55-7 = 48
January 29, 2016

math
(9 miles/ hour )(2 hours) = 18 miles note that the hours canceled top and bottom
January 29, 2016

Math
Hey- you can do that ! x-2 = 0 so x = 2 x-3 = 0 so x = 3 x+3 = 0 so x = -3
January 29, 2016

Algebra 2
boring ! x-4y-6z=-34 times 5 -7x+5y-7z=-24 times 4 +5 x -20 y - 30 z = -170 -28x +20 y - 28 z = -96 --------------------------add -23 x + 0 -58 z = - 266 now the last 2 -7x+5y-7z=-24 times 7 +5x-7y-1z=-18 times 5 -49 x + 35 y - 49 z = -168 +25 x - 35 y - 5 z = -90...
January 29, 2016

Algebra 2
http://www.gregthatcher.com/Mathematics/GaussJordan.aspx I get (4, 5, 3)
January 29, 2016

Algebra 2
http://www.gregthatcher.com/Mathematics/GaussJordan.aspx
January 29, 2016

Math
y = 4 - x x^2 + (16 - 8 x + x^2) = 16 2 x^2 - 8 x = 0 x( 2x-8 ) = 0 x = 0 or x = 4 y = 0 or y = 4 of course, symmetry :) (0,4) or (4,0)
January 29, 2016

Math
You are welcome.
January 29, 2016

Math
y = a x^2 + b x + c 12 = a (1) + b(-1) + c 5 = a(0) + b(0) + c so c = 5 15 = a(4) + b(2) + 5 7 = a - b so a = b + 7 10 = 4 a + 2 b 10 = 4(b+7) + 2 b 10 = 4 b + 28 + 2 b 6 b = -18 b = -3 then a = b+7 = +4 so y = 4 x^2 - 3 x + 5
January 29, 2016

mistake in division
assuming the first 5 x = 3 x + 6 2 x = 6 x = 3
January 29, 2016

Geometry
LOL
January 29, 2016

Geometry
Do you mean: x/3 = (x+2)/5 or x/3 = x + 2/5 ? assuming the first 5 x = 3 x + 6 2 x = 6 x = 2 assuming the second (which you wrote) x/3 = 3x/3 + 2/5 5 x = 15 x + 6 -10 x = 6 x = -3/5
January 29, 2016

math
You have to give us some dimension, like how far away
January 29, 2016

Physics
G M1 M2 / 19^2 6.67 * 10^-11 (1.45*10^4)(6.4*10^3) / 361
January 29, 2016

mathematics
I am not telling. Look at: http://www.mathsisfun.com/associative-commutative-distributive.html Hint - it starts with A
January 29, 2016

Quick calc question
calc question? LOL s(4) = 4*16 + 4 = 68 miles s(1) = 5 miles distance traveled = 63 miles time = 4 - 1 = 3 hours av speed = 63/3 = 21 miles/hour
January 29, 2016

Quick calc question
dy/dx = 2 + 4 cos 4 x so cos 4x = -1/2 4x = 180 - 60 degrees = 120 degrees = (2/3) pi so x = pi/6 or 4x = 180+60 or 4 pi/3 so x = pi/3 4 x = 360+180 - 60 = 480 =8 pi/3 so x = 2 pi/3 4 x = 360+180 + 60 = 600 = 10 pi/3 so x = 5 pi/6 too big so pi/6 , pi/3 , 2 pi/3
January 29, 2016

Physics
(1/2) a t^2
January 29, 2016

No idea
What ? what is the function ? Use parentheses if needed.
January 29, 2016

Math
15/2 is 7.5
January 29, 2016

Science
Yes, that is the only chemical reaction on your list.
January 29, 2016

PHYSICS
There is a direct answer? Please post it if you find it.
January 29, 2016

Physics help
http://www.jiskha.com/display.cgi?id=1454030373
January 28, 2016

Physics help
I have done #4 several times
January 28, 2016

Physics help
V2n = 1.20 V2e = -.00155 v = sqrt (1.2^2 + .00155^2) or about 1.2 and about North Yes, we agre Hey I am not going to do all these. You have the idea
January 28, 2016

Physics help
call m = 1 since they are the same Initial momentum N = V2n + 0 Initial momentum E = V2e + 0 final momentum N = 1.25cos44 + .92 cos 71 final momentum E =1.25sin44 -.92sin71 so V2n = 1.25cos44 + .92 cos 71 V2e = 1.25sin44 -.92sin71
January 28, 2016

please use same name
http://www.jiskha.com/display.cgi?id=1454030373
January 28, 2016

oh my
4. initial momentum N = 1800 Hey, I just did this
January 28, 2016

Algebra 1
1. geometric series a r^(n-1) a = .5, r = -2 .5 *(-2)^(n-1) 2. same deal 5 *(-1/3)^n-1 and on and on .....
January 28, 2016

college
I suspect that the proposed developer EMPLOYS only .....
January 28, 2016

Physics help
north momentum before = 1800*22 east momentum before = 3200*14 north momentum after = 5000 Vn east momentum after = 5000 Ve so Vn = 1800*22/5000 Ve = 3200*14/5000 v = sqrt (Vn^2 + Ve^2) tan angle east of north (compass heading) = Ve/Vn
January 28, 2016

before you type any more,
Go back and understand the ones Bob and I have done.
January 28, 2016

maths/physics
F = G M1 M2/r^2 dF/dr = G M1 M2 [ -2 r /r^4 } = - G M1 M2 (2/r^3)
January 28, 2016

maths/physics
V = (4/3) pi r^3 dV/dr = (4/3) 3 pi r^2 dV/dr = 4 pi r^2 OF COURSE this is the surface area of the sphere, see why?
January 28, 2016

Physics (
m = mass = rho * (4/3) pi r^3 A =cross section area = pi r^2 m/A = rho * (4/3) r d/dr (m/A) = (4/3) rho NOTE DISAGREE I guess the density of your sphere is one? Vt is when m g = C * p (1/2)Vt^2 A Vt^2 = 2 m g /(pCA) Vt = [2 m g /(pCA)]^.5 let MA = m/A then Vt = [2 g/pC]^.5 [ m...
January 28, 2016

Physics (
LOL - she sure has tough ones. It took me a while to figure out the landing on an optimal radius plant one.
January 28, 2016

Well, you asked for it :)
CHECK THAT ARITHMETIC ! I think you can get the picture from what I did but I did it fast.
January 28, 2016

Physics (Gravitation)
v = sqrt [ 2 G M/r ] v = [ 13.6 *10^-11 (10^22+r^4)/r]^.5 form is v = [ k (a+r^4)/r ]^.5 we want where dv/dr = 0 0 =dv/dr = .5 k^.5[ (a+r^4)/r ]^-.5 * [r (3 r^3)- (a+r^4)] /r^2 luckily that is zero when [r (3 r^3)- (a+r^4)] = 0 3 r^4 - r^4 = a 2 r^4 = a r^4 = a/2 but a = 10^22...
January 28, 2016

Pre-calc
Boat A east: x = 13 t Boat B north y = 20 (t-1) d = sqrt (x^2+y^2) d = sqrt [169 t^2 + 400 (t^2-2 t +1) ] d = (569 t^2 -800 t + 400 )^(1/2
January 28, 2016

World History
How much do we count slaves when figuring how many representatives a state gets in congress these day? When was it legal to drink alcohol? When was it not? What about the entire Bill of Rights, the first ten Amendments to the constitution? Have we always had an income tax? How...
January 28, 2016

Math
ds/dt = 14 t if t = 7 14 * 7 = 98
January 28, 2016

Math
58/62 = x/100 x = 93.54 % which rounds to 93.5 %
January 28, 2016

algebra
I do not understand the problem. If the bridge is 20 feet across the cut, it will stick up 20 feet when you raise it 90 degrees.
January 28, 2016

Math
The real question is: 33/88 = x/100
January 28, 2016

Math
33*100/88 = 37.5 % You did it right but to get percent from fraction multiply by 100 and your arithmetic is wrong. 33/88 = .375
January 28, 2016

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