Friday
February 12, 2016

Posts by Damon

Total # Posts: 25,219

physics
m v^2/r = .7 m g or Ac = .7 g :) 39^2 / r = .7 (9.81) r = 39^2/ (.7*9.81)
December 18, 2015

PHYSICS
v = Vi + a t v = 0 when it stops 0 = 2.7 - .12 t y = 2.25 seconds to stop d = Vi t - (1/2) a t^2 = 2.7 * 2.25 - .5 * .12 * 2.25^2
December 18, 2015

Physics
friction force up slope = mu m g cos 30 work done by friction = -80 mu m g cos 30 drop in height = 80 sin 30 = 40 ft potential energy drop = m g (40 ft) ke = (1/2) m v^2 so (1/2)m(45)^2 = 40 m g - 80 mu m g cos 30 1012 = 40(32) - mu * 32 * 69.3 1012 = 1280 - 2218 mu mu = (1288...
December 18, 2015

Random answers
Hey, try the problems. also be careful typing y-5/3=1 which is y = 8/3 is NOT (y-5)/3 = 1 which is y = 8
December 18, 2015

Math
0.9 * 59.99 = 53.99 5 * .035 * 660 = 115.50 agree
December 18, 2015

English
I agree with all four answers.
December 18, 2015

One more for Damon!
buy the pizza first 21.39 - 12.99 = 8.40 for the water 8.40/2.10 = 4 bottles or A
December 18, 2015

Math
2. 1y+1.2 y = 2.2 y so 2.2 y + 1.2 d 5. -3m + 3m + 18 = 0 + 18
December 18, 2015

Math
Hey, you asked for the average speed but you answered 8 8 is the speed OUTBOUND 24 km/3 hours = 8 8 is the speed out, not the average speed
December 18, 2015

Math
return trip took 4 hours at 6 km/h so d = 24 km (that must be to Guam from the harbor entrance buoy :) total round trip took 3+4 = 7 hours total distance = 24+24 = 48 km average speed = 48 km/7 h = 6.85 km/h
December 18, 2015

Math
Just put a 5 where I had a ? mark :) say distance d a to b time = 3 = d/v b to a time = 5 = d/(v-15) so d = 3 v and d = 5(v-15) 3 v = 5 v - 75 2 v = 75 v = 37.5
December 18, 2015

Math
outbound at speed v back at speed (v-15) say distance d a to b time = 3 = d/v b to a time = ? = d/(v-15) You did not give me all the information
December 18, 2015

Math
2.3960 = 2.3 + 0.096 + 0.0000 2.3965 = 2.3 + 0.096 + 0.0005 the 0.0005 wins in fact you would round the second one to 2.397 :) but even 2.3961 would be a winner
December 18, 2015

Math (2 Part Question)
12 d = 25 + 8 d 4 d = 25 d = 25/4 = 6 1/4 so if more than 6 days (7 or more) ==================== check how much for 6 days? without = 72 with = 25 + 48 = 73, so no pass how much for 7 days without = 84 with = 25 + 56 = 81, so yes, for 7 days cheaper with pass
December 18, 2015

Math I'm DYING!!!
You are welcome.
December 18, 2015

Hey, careful !
Need parentheses if complex numerator Perhaps you mean (y-5)/3 = 1 multiply both sides by 3 y-5 = 1*3 = 3 add 5 to both sides y -5 + 5 = 3+5 y = 8
December 18, 2015

Math I'm DYING!!!
-21 a + 16 a factor a out a (-21 + 16) a (-5) or -5a
December 18, 2015

Math I'm DYING!!!
1. y - 5/3 =1 you want to get y alone try adding 5/3 to both sides y - 5/3 = 1 +5/3 = +5/3 ---------------- add y -5/3 +5/3 = 1 + 5/3 so y = 1 + 5/3 we need a common denominator, 4 y = 3/3 + 5/3 or y = 8/3 which is 2 2/3 ===========================now check if y = 8/3 then y...
December 18, 2015

sin^-1(4/5)
well I agree with anonymous :)
December 18, 2015

Maths trigonomentry
3 cos x = 5-4 sin x 9 cos^2 x = 25 - 40 sin x + 16 sin^2 x 9 (1 -sin^2x) = 16 sin^2 x -40 sin x + 25 9 - 9 sin^2 x = 16 sin^2 x -40 sin x + 25 0 = 25 sin^2 x - 40 sin x + 16 let z = sin x 25 z^2 - 40 z + 16 = 0 (5 z - 4)(5 z - 4) = 0 wow, that was lucky sin x = 4/5 :)
December 18, 2015

Maths deduce!damon or steve plz help any one
(p-q)^2 = p^2 - 2 pq + q^2 (q-r)^2 = q^2 - 2 qr + r^2 (r-p)^2 = r^2 - 2 rp + p^2 ---------------------------add them 2 p^2 + 2 r^2+ 2 q^2 - 2(pq+qr+rp) = 2[ p^2 + r^2+ q^2 -(pq+qr+rp)] well all those squared quantities are positive so that quantity is > (pq+qr+rp)]
December 18, 2015

not my thing
sorry I suspect you have already tried expanding all that out
December 18, 2015

Social Studies
I said that partly because he established a seaport for Russia opening to the rest of Northern Europe. It was named for him for most of the history since.
December 18, 2015

Social Studies
I have to agree, but would say Navy :)
December 18, 2015

Social Studies
(or at least Magellan's crew )
December 18, 2015

Social Studies
I think B because circumnavigation is not an advance in technology.
December 18, 2015

exploration or exploitation ?
Circumnavigation is not a technology advance but an accomplishment by Ferdinand Magellan.
December 18, 2015

Math help plz?
if 3x+1 = 4 then x = 1 when x = -3, 3x+1 = -8 I have no idea, sorry
December 18, 2015

Math help plz?
I see, your graph is on a number line
December 18, 2015

do not do magic
I have no idea what your two redlines look like Please give me two points on each line (X1,Y1) , (X2,Y2) or a slope and an intercept or something.
December 18, 2015

ok, here you go
ok x = [ -8+/- sqrt (64-16m) ]/8 so (1/8) * 2 * sqrt (64-16 m) = 3 sqrt (64 - 16 m) = 12 64 - 16 m = 144 16 m = 80 m = 5
December 18, 2015

Huh ?
differs from what by 3 ? do you mean the roots differ by 3 or something?
December 18, 2015

phsice
k x = m g sin 32.5 the frequency has nothing to do with gravity or its direction. The stretching and motion and spring force is all parallel to the slope and the gravitational force component is just constant m g sin theta. omega = sqrt (k/m) as usual
December 18, 2015

history
Since Kofi Annan is an MIT graduate, he is first in line :) However there have been thousands of mediators on thousands of subjects over the years. Recently two Presidents of the US, Bill Clinton and Jimmy Carter have served as mediators getting agreements, albeit temporary, ...
December 18, 2015

Algebra 2
Well, I do not know what the parabola has to do with this. We are asked the distance from (-2,3) to (-1, -9/4) and from that same point (-2,3) to the horizontal line y = -7/4 The second part is trivial -7/4 to 3 is 12/4 + 7/4 = 19/4 we will actually have to do the first ...
December 18, 2015

Physics
.98 kg of water is .98 *10^-3 m^3 of volume mass of zinc = z mass of copper = (4.9-z) volume of zinc = z * 2.5*10^-3 m^3 volume of copper = (4.9-z)* 19.6*10^-3 m^3 so z*2.5*10^-3+(4.9-z)*19.6*10^-3 =.98*10^-3
December 18, 2015

Math
16. Find the final balance in an account with $660 invested at 3.5% annual simple interest for five years. a) $23.10 b) $115.50 c) $683.10 <------------------- d) $775.5 ================================== 660 * .035 = 23.10 per year *5 = 115.5 + 660 = 775.50
December 18, 2015

Math
7. 77 is what percent of 192? a) x/100 = 77/192; 4.01% <---------- b) x/100 = 77/192; 40.01% c) x/77 = 100/192; 77.3% d) x/100 = 192/77; 249.4% ================================ 77(100)/192 = 40.01
December 18, 2015

Physics
initial Ke = (1/2) m * 5.4^2 energy lost to friction = 0.1 * m g * 3.50 final ke = initial ke - lost energy (1/2) m v^2 = (1/2) m * 5.4^2 - 0.1 * m g * 3.50 solve for v note that the mass cancels
December 17, 2015

Math
584/421 = 1.387 which is a 38.7 % increase another way 584 - 421 = 163 163/421 = .387 so 38.7% increase Both ways are actually the same but different ways of thinking about it :)
December 17, 2015

Algraba
.07 * 25
December 17, 2015

Physics
How high? Draw it. h = L - L cos 33.6 = L(1-cos33.6) = 3(1-.833) = .501 meters up Potential energy increase = m g h = 25 (9.81) (.501) Ke = (1/2)(25) v^2 = 25(9.81)(.501) cancel the mass and solve for v = sqrt(2 g h) as usual :)
December 17, 2015

Physics!
He is at 10 meters and must jump with an initial velocity up of 5 m/s ow long until he reaches 0 meters (ground) h = Hi + Vi t - 4.9 t^2 0 = 10 + 5 t - 4.9 t^2 or 4.9 t^2 - 5 t - 10 = 0 solve quadratic for time in the air, t in seconds now the truck has to be t seconds away ...
December 17, 2015

english
as well as with
December 17, 2015

Algebra 1
or to say it better there is an infinite number of solutions. For any real x there is a real y on the line.
December 17, 2015

Algebra 1
I guess you mean y - 4 x = 1 and y - 4 x = 1 Those two lines are quite similar, in fact they intersect everywhere and there is no single point where they intersect. This is a trick problem and there is no solution.
December 17, 2015

huh?
Perhaps you copied and pasted here. That does not work on this site.
December 17, 2015

science
1 It is just a turning block.
December 17, 2015

math
if it has to be the same variable on both sides try something like: 7x + 1 = 3x + 5 + 4x -4 in other words 0 x = 0
December 17, 2015

math help plz?
You are welcome.
December 17, 2015

math help plz?
Yes, must grow more than 9 to be more than 70
December 17, 2015

Math
You are welcome.
December 17, 2015

Math
f + f+3 = 19 or 2F + 3 = 19 74 + w -6 = 3 w or 74+w = 3w+6 that means 2w=74-6 = 68 or w = 34 90-5 = 2c 85 = 2c c = 42.5
December 17, 2015

math
16 marbles 1. independent red * blue = 4/16 * 7/16 2. dependent red then blue = 4/16 * 7/15 3.in number two the probability of blue is impacted by the fact that you have taken a marble out. The two draws are not independent on problem 2
December 17, 2015

Math GP typos
Please check what you wrote what is a and what is r in a + a r + a r^2 + a r^3 ......
December 17, 2015

algebra 2
@@@@@@@@__x^2__+3x__-2_______________ x^2 + 1 | x^4 +3x^3-1x^2+5x-3 @@@@@@@@@ x^4 +0x^3+1x^2 @@@@@@@@@-------------------- @@@@@@@@@@@@@@ 3x^3-2x^2+5x-3 @@@@@@@@@@@@@@ 3x^3+0x^2+3x @@@@@@@@@@@@@@ --------------- @@@@@@@@@@@@@@@@@@@ -2x^2+2x-3 @@@@@@@@@@@@@@@@@@@ -2x^2+0x-2...
December 17, 2015

Math dump
First: We can not see the figure so can not help. Second: I see no attempt by you to do the work. I already took the subject and do not need practice. If you are having a specific difficulty, describe your attempt to surmount it.
December 17, 2015

Math
but they each play twice so double it
December 16, 2015

geometry
As far as I know the third side could be anything between 3 feet and 13 feet. 8-5 to 8+5 You need to know more about the triangle.
December 16, 2015

Social Studies
Yes
December 16, 2015

chemistry, physics
Joules in = spec heat * m * delta T so specific heat = joules/ ( m delta T) The more accurate delta T, the more accurate the resulting specific heat if you are off one degree in ten you have a 10 % error if you are off one degree in 100, you have a 1 % error
December 16, 2015

Easy Math
she mixed this 3/4 cup of sugar up with some other ingredients in a big mixing bowl. Then she baked and divided the bowl contents up into 12 brownies
December 16, 2015

Easy Math
(3/4) / 12 = 3/(4*12) = 1/(4*4) = 1/16
December 16, 2015

Math
-10 - 16 = -26
December 16, 2015

math
we can get more careful working with each column 8 in the ones column is fine but 24*10 = 20*10 + 4*10 = 2*100 + 4*10 so 4 in the ten column and add 2 over to the hundred column 12*100 + 2 * 100 = 14*100 = 10*100 + 4*100 = 1000 + 400 so I have 1 in the thousands 4 in the ...
December 16, 2015

math
300 * 4 = 1200 60 * 4 = 240 2 * 4 = 8 then add 1200 + 240 + 8 = 1448 this uses the distributive property 362 = 3*100 + 6 * 10 + 2 4 * 362 = 4 (3*100 + 6 * 10 + 2) = 12*100 + 24*10 + 8
December 16, 2015

math
h^2 + 35^2 = 50^2
December 16, 2015

Physics
old bear solution http://www.jiskha.com/display.cgi?id=1229011401
December 16, 2015

Phsics dump
again
December 16, 2015

PHYSICS getting tired of homework dump
enough already
December 16, 2015

PHYSICS - method again !
look at: http://www.jiskha.com/display.cgi?id=1338312530
December 16, 2015

physics homework dumping
Now wait a minute, I already took this subject in 1954. I do not need practice. If you need help that is one thing but I see no sign of your attempts.
December 16, 2015

physics
time in air = 166/26 = 6.38 s so what stays up that long? well, it spends half that time going up t = 3.19 s upward v = Vi - g t at top v = 0 0 = Vi - 9.81(3.19) Vi = 31.3 m/s initial speed up
December 16, 2015

physics
F = - .59 * m g so a = - .59 g v = Vi + a t v = 16.5 - .59 (1.35)
December 16, 2015

ignore what I did
I did not understand your question.
December 16, 2015

ALGEBRa 2
2 x^3 - 4 x^2 + 5 x + 2 = 0 ?????? I suspect a typo and you do not say what you want. I assume roots. using http://www.mathportal.org/calculators/polynomials-solvers/polynomial-roots-calculator.php x1=−0.31075 x2=1.15537+1.37229∗i x3=1.15537−1.37229∗i
December 16, 2015

physics
find friction force -.66 * m g = -.66 * m * 9.81 = -6.47 m (so slows down at .66 g but forget I said that) a = F/m = -6.47 m/s^2 v = 19 - 6.47 t at t = 1.31 v = 19 - 6.47(1.31) = 10.5 m/s
December 16, 2015

physics
a = Ai e^-kt da/dt = -kAi e^-kt 518 = -k e^-7k 156 = -k e^-17k 518/156 = e^-7k / e^-17k = e^10k ln 3.32 = 10 k 1.2 = 10 k k = .12 I guess you can take it from there
December 16, 2015

using elimination
3 x + y = 0 3 x + 2 y = 6 --------------- -y = -6 so y = 6 then x = y/-3 = -2
December 16, 2015

algebra
use -3x for y (It is called "substitution") 3 x + 2 (-3x) = 6 3x - 6 x = 6 -3 x = 6 x = -2 y = -3x = 6
December 16, 2015

Math
x is the same for both points graph that, vertical line slope undefined
December 16, 2015

physics
look at http://www.jiskha.com/display.cgi?id=1338312530
December 16, 2015

Physics Sound Waves
If the listener does not move Doppler: Fl = { v/(v+vs) ] Fs Fl is frequency heard Fs is source frequency vs = speed of source AWAY from listener v = speed of sound here: when it is coming at you FL = [345/(345-vs) ] 450 going awy: Fl = [ 345/(345+vs) ] 450 so 22= 345*450 / [1...
December 16, 2015

physics
normal force = m g cos 21.8 max friction force down ramp = .17 m g cos 21.8 gravity force down ramp = m g sin 21.8 so total force down ramp = m g (.17 cos 21.8 + sin 21.8) work done by friction and against gravity sliding up a distance d = d m g (.17 cos 21.8 + sin 21.8) that ...
December 16, 2015

Math
yes, but where is it zero? function is horizontal when -8x^3+6x = 0 that happens when x (-8 x^2 + 6) = 0 x (-4x^2 + 3) = 0 x = 0 or x^2 = 3/4 x = + or - (1/2)sqrt (3) -------------------- now what is second derivative at those points? d^2y/dx^2 = -24 x^2 + 6 when x = 0, that ...
December 16, 2015

math
well, I am sorry but I just plain have to use algebra had n at the start sold 24 so have n-24 at noon sold 2/7 of (n-24) and have n/2 so n -24 - (2/7)(n-24) = n/2 14 n - 336 - 4 n + 96 = 7 n 3 n = 240 n = 80 ---------------------------- check n = 80 sold 24 so have 56 sold (2/...
December 16, 2015

Physics
What pathetic pullers! You do not say derees to what. I will assume to the x axis and not to north. x components: 16 cos 64 + 15 cos 136 + 12 cos 195 7.01 - 10.79 - 11.59 = -15.3 y components: 16 sin 64 + 15 sin 136 + 12 sin 195 = 21.7 magnitude = sqrt (21.7^2 + 15.3^2) ...
December 16, 2015

math app
u+c = 20 u-c = 6 ------------subtract
December 16, 2015

La
a = 5 r = -3 an = a r^(n-1) which is the very definition of a geometric sequence :)
December 16, 2015

Physics
LOL F = G Me m/r^2 F/m = G Me/r^2 = 9.8 F/Me = G m/r^2 = 9.8 (m/Me) so 9.8 (44/5.98*10^24)
December 16, 2015

S.s
Staying out of this! (from New England)
December 16, 2015

Social Studies
That would have been my guess.
December 16, 2015

Social Studies
Am I allowed to guess ? :)
December 16, 2015

Physics
Well, of course if you happen to be a spear fisherman who spears fish from above the water, you need to correct for refraction at the surface. More commonly, if you wear glasses or use binoculars or a telescope or a microscope, lenses work by the diffraction of light at the ...
December 16, 2015

Physics
work done by tugboat = 6000 * 4000 = 24 * 10^6 Joules work done by water = -500*4000 = -2*10^6 Joules (negative because force is opposite to motion) net work done on ship = 22*10^6 Joules Note unbalanced force on ship leads to acceleration but we do not care. a Joule is a ...
December 16, 2015

Math
You are welcome.
December 16, 2015

Math
Yes, you got it.
December 16, 2015

Math
45/33 = 1.3636363636363636363636.....
December 16, 2015

Lowndes High School
perhaps there was a drawing to go with this, for example with two congruent angles and a congruent side between them ?
December 16, 2015

Math
You are welcome.
December 16, 2015

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