Monday
September 26, 2016

Posts by Damon

Total # Posts: 27,152

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

Ihave about ten times no C in NaCl
Na = sodium Cl = chlorine no C, carbon
January 28, 2016

Science
I suspect that you could separate these by distillation
January 28, 2016

Math
coin 1 **h t coin 2 h 6 4 coin 2 t 4 0 p(6 points) = 1/4 p(4 points) = 1/2 p(0 points) = 1/4 (1/4)6 + (1/2)4 = 2 + 1.5 = 3.5 so I agree with you
January 28, 2016

Physics
weight = 2 * 10^3 * 9.81 = 19.62*10^3 N mechanical advantage = .75/.005 = 150 (19.62/150)* 10^3 = 130.8 N
January 28, 2016

Science
salt only has sodium (Na) and Chlorine (Cl) They are however both compounds which are held together by chemical bonds.
January 28, 2016

physics
10 protons * 1.6*10^-19 C per proton = 16*10^-19 C per atom 16*10^-19 C/atom * 6*10^23 atoms/mol = 96*10^4 C/mol 96*10^4 C/mol * 1 mol/20.2 g = 4.75*10^4 C/gram 4.75*10^4 C/gram * 800 grams = 3801*10^4 = 3.8 *10^7 C Luckily the neutral atoms have an equal number of electrons ...
January 28, 2016

physics
Oh k is about 9*10^9
January 28, 2016

physics
F = m a = k Q1 Q2/d^2 so a = F/m m = 27 g = .027 kg Q1 = 32*10^-6 Q2 = -22*10^-6 so F is attractive between them F=(1/.027)k (32)(22)(10^-12)/.79^2
January 28, 2016

physics
F = k Q1 Q2 / d^2 = 9*10^9 (46)(46)/(36*10^6)
January 28, 2016

Science
Na = sodium Cl = chlorine no C in there
January 28, 2016

physics
T = 20.6/4 = 5.15 seconds period between crests wave goes 2.97 m in 5.15 seconds speed of crest = 2.97/5.15 m/s frequency = 1/T since you did not include a question, I am guessing that is what you want
January 28, 2016

Calculus
ln [(x+1)/(x-1)] = 2 (x+1)/( x-1) = e^2 = 7.39
January 28, 2016

maths science and geography
a r^4 = 4 a r^2 r^2 = 4 r = +/- 2 -2
January 28, 2016

Maths - Differentiation
4 x^2 y = 64 so y = 16/x^2 I guess it has a square bottom and height y Area = area top and bottom + 4 x y = 2*4 x^2 + 4* 2 x y = 8 x^2 + 8 x y = 8 x^2 + 8 x (16/x^2) = 8 x^2 + 128/x agreed dA/dx = 16 x -128/x^2 = 0 at max or min 16 x^3 = 128 x^3 = 8 x = 2 c) d^2A/dx^2 = 16 +...
January 28, 2016

history .
I would say fear and anger
January 28, 2016

Maths - Differentiation
C) the function graph is horizontal when dy/dx = 0 (1/16) x^2 -1/x^2 = 0 (1/16) x^4 = 1 x^4 = 16 x = + or - 2 D) at x = -2 d^2y/dx^2 = (1/8)(-2) +2(1/-8) negative so headed down, a maximum at x = + 2 POSITIVE SO HEADED UP, MINIMUM
January 28, 2016

Math
7*100 + 16*10 + 3 700 + 160 + 3 800 + 60 + 3 863
January 28, 2016

Mathematics
a = (2/3) b + 1/3 use in eqn 2 3 b = 5 [(2/3) b + 1/3 ] - 3 3 b = (10/3)b + 5/3 - 3 9 b = 10 b + 5 - 9 b = 9-5 b = 4 3a = 2(4) +1 = 8+1 a = 3
January 28, 2016

Science
1. yes 2. yes 4. yes 5. yes 6. yes 7. yes 8. yes 9. yes 10. I would say boiling and evaporating since they are really the same. I am not sure you can filter dissolved sugar out of water except perhaps by reverse osmosis
January 28, 2016

Calculus
inverse would be time for a specific population 1+749 e^-.15t = 7500/p 749 e^-0.15 t = (7500-p)/p e^-.015 t = (7500-p)/(749 p) e^.015t = 749 p/(7500-p) .015 t = ln [ 749 p] - ln [7500-p)] t = 66.7 [ln 749 p - ln(7500-p)] we had 10 when t was 0 so check t = 66.7[ ln 7490 - ln ...
January 28, 2016

Pre-calculas
Is the point at the bottom or the top? whichever way you draw it Volume of a cone = (1/3)pi R^2 x where r is the radius of the surface and x is distance from the tip r/x = 9.5/ 16 = .594 so r = .594 x v = (1/3) pi (.594x)^2 x v = .369 x^3 dv/dx = 1.11 x^2 dv/dt = 1.11 x^2 dx/...
January 27, 2016

Math
yes, only one that has angles less than 90 and adds to 180
January 27, 2016

physics
Vi = initial speed up u = constant horizontal speed find t, time in air Vi = 135 sin 18.3 = 39.25 u = 135 cos 18.3 = 128.2 d = u T find T the time in air v = Vi - 9.8 t at top where v = 0 and t=T/2 0 = 39.25 - 9.8 t t = 4.005 s so T = 2 t = 8.01 seconds in the air d = u t = ...
January 27, 2016

Math
1700 * 100 / 8500 = 20 %
January 27, 2016

Algebra
n n+2 n+4 n+6 ---- 4 n + 12 = 80 4 n = 68 n = 17 17, 19 ,21 ,23
January 27, 2016

Math
make a sketch !!! a diagonal would for example be from B to D change in x = 1 - -1 = 2 change in y = -3 - +3 = -6 sqrt (2^2+6^2) = sqrt 40 = 2 sqrt 10
January 27, 2016

Algebra
n + n+2 = 1306 2 n = 1304 n = 652 n+2 = 654
January 27, 2016

Math
Agree, only one with all less than 90 and adds to 180
January 27, 2016

Math
Remember 40% LOSS is 60% LEFT :)
January 27, 2016

Math
.6 * 300 = 180 left after 40% trim .4 * 180 = 72 left to eat
January 27, 2016

math
You are welcome.
January 27, 2016

math
1.03^10 = 1.344 times 19900 = 26744 You got it
January 27, 2016

Algebra
n + n+1 + n+2 3 n + 3 = 930 3 n = 927 n = 309 and 310 and 311
January 27, 2016

English
because gh is two consonants http://www.howtospell.co.uk/doubling-up-rule
January 27, 2016

Physical Science
Yes, assuming electromagnetic (not water or sound or whatever)
January 27, 2016

Math
(200/5000)100 = 20000/5000 = 20/5 = 4%
January 27, 2016

Algebra
n + n + 1 = 529 2 n = 528 n = 264 n+1 = 265 add them to check
January 27, 2016

math
total rise = 112 - 149 = -37
January 27, 2016

math
you have 12 girls put one girl and 3 boys in each of 12 groups
January 27, 2016

Math
4n+2 = 14 ? 4 n = 12 n=3 2n = 6 2n+2 = 8
January 27, 2016

physics
Rx = 15 cos 250 = -5.13 m Ry = 15 sin 250 = -14.1 m ============================ new one is - 2 times old 250 - 180 = 70 degrees is opposite Rx = 30 cos 70 = 10.3 Ry = 30 sin 70 = 28.2 R^2 = (Rx^2+Ry)^2 = 30^2 (sin^2+cos^2) = 30^2 so it is 30 of course direction is the old ...
January 27, 2016

physics
I rounded .115 to .12 in part a (as instructed :) If they use 4.9 (1.15)^2 they would get 6.48 which rounds to 6.5
January 27, 2016

physics
t = distance/speed = .115 * 10^-6 seconds which is 1.2 *10^-7 seconds h = (1/2) g t^2 h = 4.9 (1.44)(10^-14) h = 7.1 * 10^-14 meters
January 27, 2016

Physics
F = k Q1Q2/r^2 here r = .115 so let (k/r^2) = c constant Fnorth = -(3.17*3.96*10^-12)c Feast = +(3.17*5.03*10^-12)c magnitude = sqrt (Fx^2 + Fy ^2)
January 27, 2016

Physical Science
solids are harder to squish. look here: https://www.khanacademy.org/science/physics/mechanical-waves-and-sound/sound-topic/v/relative-speed-of-sound-in-solids-liquids-and-gases
January 27, 2016

physics
C runs 4.09 t meters C runs 4.28 t meters 4.28 t - 4.09 t = 94
January 27, 2016

les/math
original box x (2x)(5x) = 80 x^3 = 8 so x = 2 2x = 4 5x = 10 now new box 4 * 6 * 12 = 288 cm^3 increase = 288 - 80 = 208
January 27, 2016

physics
1490 + 25,000 tan 2.6 = h h = 1490 + 1135 h = 2625 meters
January 27, 2016

Math
Yes, could have any old value, including the same.
January 27, 2016

math
h * 6 = 102 h = 102/6 = 17 17 what though? inches,feet meters? decimeters? elbows? miles? kilometers? Is Rita a doll or a dinosaur?
January 27, 2016

Physics
- (1.2*10^4 )(1.6*10^-19) = 1.9 *10^-15 C = 1.9 * 10^-9 µC
January 27, 2016

math
a taxi ride costs 5 dollars to start the meter and then 4 dollars per mile. I have 37 dollars. How far can I ride? ( I guess I will not leave a tip :( 4 x = 37 - 5 4 x = 32 x = 8 miles
January 27, 2016

Math
ln(2x+3)^4 = 11 e^ln(2x+3)^4 = (2x+3)^4 = e^11 (2x+3) = (e^11)^.25 = e^2.75 = 15.64 2x = 12.64 x = 6.32
January 27, 2016

Math
Hey Rita, read what you wrote. We have no idea what your scale ratio is hint ratio of areas = ratio of lengths^2 2/1 in length is 4/1 in area (and 8/1 in volume)
January 27, 2016

history .
I agree with A for both. However I am not a history teacher.
January 27, 2016

Math
Log2(x)+log2(x-3)=2 2^[Log2(x)+log2(x-3)] =2^2 2^log2(x^2-3x) = 2^2 (x^2-3x) = 4 x^2 - 3 x - 4 = 0 (x-4)(x+1) = 0 x = 4 or x = -1
January 27, 2016

Math
2log6(4x)=0 log6 (16 x^2) = 0 6^log6 (16 x^2) = 16x^2 = 6^0 = 1 so x^2 = 1/16 x = 1/4 normally I would say also -1/4 but try to take the log of -1 :)
January 27, 2016

Physical Science
No, I disagree. It has to transfer heat to something colder, like a vat of liquid air or the surface of Lake Superior in February.
January 27, 2016

Functions 11
well b^2-4ac = 81-24k if that is positive, two real roots if it is zero, you have one root twice (the parabola just bounces off the x axis at x = -b/2a) if it is negative there are no REAL roots (although there are two complex conjugate solutions)
January 27, 2016

Chemistry 101
.785 v = 2 v = (2/.785) cm^3
January 27, 2016

Physics
Newtons force = F = .1 kg * 9.81 x = 0.10 meter k = F/x = 9.81 N/m
January 27, 2016

Math
use -4y for x in the second equation -4 y + 5 y = 2 so y = 2 then x = -4(2) = -8 (-8 , 2)
January 27, 2016

Physics
I took this in 1955 and do not need practice. If you get stuck I will help but I will not do all the problems for you. By the way in Naval Architecture we have a term called "tons per inch" for small changes in draft. It proportional to rho g * area of water line ...
January 27, 2016

Physics
(1000 kg/m^3 * volume) - 1.8 kg
January 27, 2016

Physics
You mean 1.8 * 9.81 N
January 27, 2016

PHYSICS
weight component down slope = m g sin A = force component up slope = F 50 (1/2) = 25 N = F
January 27, 2016

Physics
The kinetic energy alone is (1/2) m v^2 = 212 * 10^12 so there is a typo somewhere either in the problem statement or in the answer.
January 27, 2016

Math
Matt had x May had 3x 4 x - 50 = 70 4 x = 120 x = 30 ======================= check Matt 30 May 3*30 = 90 sum = 120 120 = 50+70
January 27, 2016

math
tan 30 = h/a tan T = h/2a tan T = (1/2) tan 30 T = 8.21 degrees
January 27, 2016

W Hist
semiconductors sitting around staring at screens no horse messes stinking up the city streets
January 26, 2016

Math
6 * 3 * 2 = 6 * 6 = 36 ft^3
January 26, 2016

math
2*2*2*2*2*2
January 26, 2016

Physics
vertical problem: Vi = 68 sin 25 = 28.7 m/s h = Vi t -4.9 t^2 h = 28.7 t - 4.9 t^2 horizontal problem: u = 68 cos 25 = 61.6 m/s t = 50/61.6 = .811 s so h = 28.7(.811) - 4.9(.811^2)
January 26, 2016

Pre Algebra
-1 11/16 + 4 1/6 = - 27/16 + 25/6 sure enough = -81/48 + 200/48 agree = 119/48 = 2 23/48 yes ============================ NO! -1 33/48 + 4 8/48 = 3 -25/48 = 2 + 48/48 -25/48 = 2 + 23/48
January 26, 2016

?
Please proof read initially at rest maybe? 12 what? /s^2 meters, feet ? 205 what? seconds, meters ? feet? miles? after 205 what again? 12 m/s^2 for how long ? Is this after the first question using that final for this initial velocity?
January 26, 2016

math
Yours is much better. I got off on that both queens tack :)
January 26, 2016

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