Saturday

October 22, 2016
Total # Posts: 27,510

**physics**

Fx = -a x^4 I assume you mean F= -25 x^4 dW = F dx = -25 x^4 dx W = -(25/5)x^5 at x = 1.25-at.75 W = -5 (1.25^5 - .75^5)

*April 30, 2016*

**Maths**

try reading here: http://www.mathsisfun.com/algebra/factoring.html

*April 30, 2016*

**math**

Yes, to do it on the number line start at 0 go left 8 to - 8 go right 14 to +6

*April 30, 2016*

**check list of answers below**

This has been asked over and over and over again, look below.

*April 30, 2016*

**typo**

You mean V = (4/3) pi r^3 dV/dt = (4 pi r^2) dr/dt (You really do not need calculus. It is the surface area times dr/dt)

*April 30, 2016*

**MATH**

No, because 3+5 = +8 , not 15

*April 30, 2016*

**math**

-9 + 5 + x = -1 -4 + x = -1 x = +3

*April 30, 2016*

**MATH**

-4 - 2 = -6

*April 30, 2016*

**Geography -Yr10**

During the second half of the 19th century, river shipping was of great importance, but, with growing competition from railways and demand for irrigation water (first used at Mildura in 1886), navigation practically ceased. ================================ In other words they ...

*April 30, 2016*

**Math**

weight at top = 15 -.1*50 = 10 average weight = (15+10)/2 = 12.5 12.5 * 50 = 625 ft pounds

*April 30, 2016*

**Math**

You are welcome.

*April 30, 2016*

**Math**

No, same answers both ways.

*April 30, 2016*

**Math**

I used the kinematics because I did not know if you knew how to integrate velocity to get distance.

*April 30, 2016*

**Math**

oh well v(t)= 38-2t or dx/dt = 38 - 2 t then x = c + 38 t - (1/2)(2)t^2 c = x when t = 0 call it 0 here x = 38 t - t^2

*April 30, 2016*

**Math**

I do not know if you know calculus or if you have kinetatic equations in your text. What we have here is a constant acceleration of -2 ft/s^2 a. 0 = 38 - 2 t 2 t = 38 t = 19 s b. d = Vi t + (1/2) a t^2 = 38 (19) - 19^2 = 19(19) = 361 feet or use average speed for 19 seconds...

*April 30, 2016*

**Math**

yes, circumference = pi D = 8.4 pi

*April 30, 2016*

**Geometry**

yes, If you use google search type in 45 yards = cm and see what happens

*April 30, 2016*

**math**

.6 * 255.5 = 153.3 leaked out .3 oz/s * t = 153.3 oz t = 153.3 /0.3 = 511 seconds

*April 30, 2016*

**Rt**

31+n = 2(7+n) 31 + n = 14 + 2 n 17 = n so in 17 years then check 7 + 17 = 24 31 + 17 = 48 sure enough twice 24

*April 30, 2016*

**Geography - Yr10**

Note particularly : " .....From the 1970s the emphasis changed to community facilities such as libraries and parks, maintenance of local roads, town planning and development approvals, and local services such as waste disposal. Child care, tourism and urban renewal were ...

*April 29, 2016*

**Geography - Yr10**

I see from your other question about Murray River that you are probably in Australia. I know little about Australia, being from Massachusetts in the USA but perhaps look here: http://en.wikipedia.org/wiki/Local_government_in_Australia

*April 29, 2016*

**Math (please help)**

(1/4)in * 6 ft/in = 1.5 ft/side so 2.25 ft^2 /square Bathroom = 2.25*6=13.5 ft^2 Bedroom = 2.25*20= 45 ft^2 Living room = 2.25*28=63 ft^2 tiny house a. 5 * 13.5 b. (18/9)(45+63) c. tile is $5/ft^2, carpet is $2/ft^2

*April 29, 2016*

**science**

Did it start at zero speed? If so 300 = (1/2) a t^2 = .5 a *225 a = 600/225

*April 29, 2016*

**math**

(4/3)x - 4 - (6/5)x + 9 (20/15)x - (18/15) x + 5 (2/15) x + 5

*April 29, 2016*

**physics**

The speed is constant. All you need is the vertical component. (30/4) cos 45

*April 29, 2016*

**math**

new length = 15+x new width = 12+x so the last one

*April 29, 2016*

**Pre Calculus**

L = 13 - 2x w = 11 - 2x V = (13-2x)(11-2x)x V = (143 - 48 x + 4 x^2)x V = 4 x^3 -48 x^2+143 x find where dV/dx = 0 0 = 12 x^2 - 96 x + 143 x = [ 96 +/- sqrt(9216-6864)]/24 x = [96 +/- 48.5 ]/24 x = 1.98 in or x = 6.02 (too big, no width left) so about 2 inches high

*April 29, 2016*

**physics**

.388 kg ice melt it and warm it to 45 C .388 [ 333,000 + 45(4186) ] = 202,292 Joules into what was ice = m [2256,000 + 55(4186) ] = 2,486,230 m m = 202,292/2,486,230 = .0814 kg = 81.4 grams

*April 29, 2016*

**Maths**

each pipe does one tank/12 hr call that 1 tank/12 hr pipe 1 tank/12hrpipe * 4 pipe * 2 hr = (8/12) tank = 2/3 of a tank

*April 29, 2016*

**Math**

835 cm / 15 cm = 55 2/3 55 pieces + 2/3 * 15 = 10 cm left over

*April 29, 2016*

**maths**

100 - 30 = 70 .7 * 60 = 42

*April 29, 2016*

**Physics**

I assume you made a typo and mean 1.6 * 10^15 Liters 1 liter water = 1 kg a pint is a pound the world around :) m g h = 1.6*10^15 kg * 9.81 m/s^2 * 143 m = 2245 * 10^15 = 2.245 * 10^18 Joules

*April 29, 2016*

**Math**

probability that she sees a bird on any old day = 18/30 = 0.6

*April 28, 2016*

**huh?**

180 was the answer, .3 * days 420 is days you do NOT hear thunder.

*April 28, 2016*

**college mathematics**

yes --- angle side angle

*April 28, 2016*

**college mathematics**

yes --- side side side

*April 28, 2016*

**homework**

assume you mean x^(8/9) pi y^2 dy from y = 0 to y = 1 pi x^(16/9) dy but dy = (8/9) x^-(1/9) dx so (8/9)pi x^(15/9)dx from 0 to 1 (8pi/9) (9/24)x^(24/9) (8 pi/24) = pi/3

*April 28, 2016*

**Physics**

I guess you mean north of east and east of north east = 1000 cos 40 + 500 sin 20 north = 1000 sin 40 + 500 cos 20 east = 937 north = 1113 distance = sqrt(937^2+1113^2) tan angle north of east = 1113/937

*April 27, 2016*

**Math**

width = 1.5 1.5 * 3 * 6 = 18+9 = 27 ft^3 which is one cubic yard

*April 26, 2016*

**Science**

calibrate it. Mark points on it that are he same temp as the real thermometer shows, say in cold water and hot.

*April 26, 2016*

**Math**

7 * 2.5 * h = 175 h = 10

*April 26, 2016*

**math**

Can not, sorry, rules.

*April 26, 2016*

**math**

Note above that she answered a question at 6:41 EDT

*April 26, 2016*

**math**

Your guess is as good as mine.

*April 26, 2016*

**math**

1, 89 , 67 , 89 , 7, 5 , 45 , 7

*April 26, 2016*

**math**

What do you mean? They all are except 0.

*April 26, 2016*

**math**

I suppose

*April 26, 2016*

**math**

Hi neighbor

*April 26, 2016*

**math**

1*1*5/(2*2*6) = 5/24

*April 26, 2016*

**Math**

I said 280 + 4 w = 420 so 4 w = 140 w = 35 mph wind speed now go back and get v

*April 26, 2016*

**Math**

v = 140 + w (140+2w)2 = (140 +w -w )3 = 420 280 + 4 w = 420 etc

*April 26, 2016*

**math**

we need something else with y = 16 and with x = 4 so (4,16) DRAW IT !!!!!!!!

*April 26, 2016*

**Calculus**

how far apart are they ? t in hours sqrt (x^2 + y^2) =sqrt [(50t)^2 + (60 t)^2] so d = (2500 + 3600)^.5 t d = 78.1 t so separation speed is 78.1 mph all the time

*April 26, 2016*

**math**

well they have to add up to one and there are 6 sides p(1) = n prime p(2) = 2n prime p(3) = n prime p(4) = 2n p(5) = n prime p(6) = 2n sum of p s is one 9 n = 1 n = 1/9 primes are 5n or 5/9

*April 26, 2016*

**physics**

Angular momentum after = angular momentum before angular momentum before = I w = 1.4*10^-3 * .33 = .462 * 10^-3 angular momentum after = (1.4*10^-3 + 4.2*10^-3) w so w = .462/5.6 = .0835 rad/s

*April 26, 2016*

**History**

Actually I think the historical advantage of rivers is that you can float down them easily and if the wind happens to blow up river commonly, you can get up the river easily as well. (the Nile :)

*April 26, 2016*

**History**

In fact, more often than not, rivers are more like highways than barriers. Of curse as you know I feel the same way about oceans, but that is because I use them.

*April 26, 2016*

**math**

c(27)= 10 * 27 + 26 = 270+26 = 296 so (27 , 296) c(39) = 10*39 + 26 = 390+26 etc

*April 26, 2016*

**math**

just use 27 for n and do the arithmetic then do the others.

*April 26, 2016*

**History**

Yes, agree with Astral.

*April 26, 2016*

**History**

Not on my map. I also have charts of the South China Sea and Straits of Malacca and Indian Ocean that hint at serious ancient interactions. Your text was not written by a seafarer.

*April 26, 2016*

**math**

up two in x, down one in y slope = -1/2 so y = -x/2 + b 1 = -2/2 + b b = 2 so y = -x/2 + 2

*April 26, 2016*

**maths**

total time = 45 min .75 hour 72 t + 48(.75-t) = 48 etc

*April 26, 2016*

**math**

v = Vi - 32 t 0 = 96 - 32 t t = 3 s h = Vi t - 16 t^2 h = 96(3) - 16(3)^2 h = 288 - 144 = 144 ft

*April 26, 2016*

**American history**

yes

*April 26, 2016*

**American history**

Agree

*April 26, 2016*

**Physics**

Of course there is a more basic way to look at this. F = m a = -mg so a = - g = -10 so v = -gt = -10 t so+- initial speed * t - (1/2)(10) t^2 0 = 3 + 0 - 5 t^2 t = sqrt(3/5) so v = -10 sqrt(3/5) = -sqrt(60) = -2 sqrt 15 = -7.75 which we knew

*April 26, 2016*

**Physics**

sure, as it drops it picks up speed. The loss in height potential energy, m g h, turns into kinetic energy, (1/2) m v^2 In other words: (1/2) m v^2 = m g h v^2 = 2 g h v = sqrt(2gh) which is something a lot of us remember. Note that the mass does not matter. In a vacuum, a ...

*April 26, 2016*

**Mathematics**

neither 8 + 2 n = 32 2 n = 24 n = 12

*April 26, 2016*

**Math**

w+2a = 18 h+2a = 11 w h = 60 so w = 60/h (60/h) + 2 a = 18 but a = (11-h)/2 60/h + 11 - h = 18 60 + 11 h - h^2 = 18 h h^2 + 7 h - 60 = 0 check my arithmetic and solve quadratic

*April 26, 2016*

**Mathematics**

still 12

*April 26, 2016*

**Economic**

google supply and demand

*April 25, 2016*

**Algebra**

http://www.jiskha.com/display.cgi?id=1461567386#1461567386.1461580442

*April 25, 2016*

**physics**

http://www.jiskha.com/display.cgi?id=1461575534

*April 25, 2016*

**Physcis**

How many Joules are needed? power = Vi = 110*7 = 770 watts energy = power*time = 770*600seconds 462,000 JOULES needed = m g h = m (9.81)(10) so m = 4709 Kilograms of water there are 1000 kg of water/meter^2 so 4.709 cubic meters of water

*April 25, 2016*

**Algebra I DONT KNOW HOW TO DO 3 VARIABLES**

x = 2 - y - 5z 4(2 - y - 5z) -3y + 5z = 3 3(2 - y - 5z) -2y + 5z = 1 8 - 4y - 20z - 3y + 5z = 3 6 - 3y - 15z - 2y + 5z = 1 -7y - 15z = -5 -5y - 20z = -5 or y = 1 - 4z -7(1-4z) - 15z = -5 7 + 28z -15 z = -5 13 z = 2 SO I get: z = 2/13 y = 13/13 - 8/13 = 5/13 x = 26/13 - 5/13 -...

*April 25, 2016*

**Physics help**

Is this the same set of waves? Do you have a box where you store leftover waves? If waves go by you in deep water with high speed and long wavelength for example, they will slow down and become shorter as they approach a shallow beach. However the same number hit the beach per...

*April 24, 2016*

**Math**

m = k n/p^2 3 = k (2/1) k = 3/2 m = (3/2) n/p^2

*April 24, 2016*

**Math, algebra 2**

arithmetic sequence first term is one so a = 1 d = -1 sum =120 see http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html

*April 24, 2016*

**math**

5/4 inch * 4 miles/inch = 5 miles (ignoring the change in altitude :)

*April 24, 2016*

**math**

4 + 5 + 4 = 13 unless you mean (x+20) / (x+4) which is 24/8 = 3 watch your mathematical grammar.

*April 24, 2016*

**life orientation ?**

Is it a violation of my human rights to be asked the same question time after time, day after day, week after week until I am ready to scream?

*April 24, 2016*

**maths**

a, ar ar^2 ar^3 ar^4 a r^2 + a r^3 = -4/3 a r^3 + a r^4 = -4/9 a r^2 (1 + r) = -4/3 a r^3 (1 + r) = -4/9 -4/(3 a r^2) = -4/(9 a r^3) so r = 1/3 a(1/9)(4/3) = -4/3 a = -9 so: -9 -3 -1 -1/3 -1/9 and -1/27

*April 24, 2016*

**maths**

to get -1 + 0 i z^5 = 1 cos 180 + i sin 180 That should get you started

*April 24, 2016*

**math**

9+3 8+4 7+5 6+6 and reverse

*April 24, 2016*

**precalc**

θ = 180 + cos^-1 (1/3) = 180 + 70.5 = 250.5 ϕ = 180 - sin^-1 (1/4) = 165.5 so we want tan (416) = 1.48

*April 24, 2016*

**Calculus**

I get d^2s/dt^2 = 4 sin 3 t ds/dt = v = -(4/3)cos 3 t + c when t = 0 , v = 1 1 = -4/3 + c c = 7/3 v = -(4/3)cos 3 t + 7/3 s = -(4/9) sin 3 t + 7 t/3 + k 6 = k s = (1/9)(21 t - 4 sin 3 t +54)

*April 24, 2016*

**algebra**

1/R = 1/R1 + 1/R2 or R = R1 R2 /(R1+R2) = 8*12/(20) = 4.8 Ohms

*April 24, 2016*

**math**

L = k m^(1/3) 15 = k (125)^(1/3) = k (5) k = 3

*April 23, 2016*

**converting parabolic equations**

huh? multiply x + 15= 8(y^2 - 2y + 1) 8 y^2 - 16 y + 8 = x +15 x = 8 y^2 - 16 y -7

*April 23, 2016*

**Mathematics**

maybe something like let z = ln x dz /dx = 1/x dx = x dz ∫ 1/[x(1+lnx)^2] dx ∫ dz/[ 1+z]^2

*April 23, 2016*

**World History**

Even without an invasion or nuclear bombs Japan was all done. Between the American submarine fleet and surface/air fleets, they were being strangled. Japan does not have oil or many other vital supplies. Without merchant ships to and from Southeast Asia and elsewhere, they ...

*April 22, 2016*

**Math**

Oval? If it were circular, the fence would be 2 pi R long where R is radius (in feet, three times radius in yards) If it is an ellipse, then a = half length of long axis b = half length of short axis Perimeter = 4 a E(k) where k^2 = 1 - (b/a)^2 and E(k) is an elliptic integral...

*April 22, 2016*

**Complex number cartesian form**

Well, that was entertaining :)

*April 22, 2016*

**Complex number cartesian form**

yes r^2 = 4 + 4 = 8 so r = sqrt 8 = 2 sqrt 2 - 2 - 2 i is in quadrant 3, 45 degrees below -x axis Theta = pi + pi/4 = 5 pi/4 or 180 + 45 = 225 degress so x = 8^.5 e^(5 pi i/4) now raise to power five raise (8^.5)^5 = 8^2.5 multiply angle by 5 25 pi/4 = 24 pi/4 + pi/4 which is ...

*April 22, 2016*

**Math**

-4 = x^2 - 4 x = 0 then y = -4 A

*April 22, 2016*

**Physics**

1. U = (1/2) k x^2 =(1/2)(3.792*10^2) (1.42^2)(10^-2) = 3.82 Joules 2. same 3.82 Joules 3. 3.82 + m g h = 3.82 + .294(9.81)(0.960) = 6.59 Joules 4. How long does it take to fall .96 meters? .96 = (1/2)(9.81)(t^2)

*April 22, 2016*

**algebra!!!!**

do you mean y = x^2 - 2 x - 6 ???? if so then 4 x + 10 = x^2 - 2 x - 6 x^2 - 6 x - 16 = 0 (x-8)(x+2) = 0 x = +8 or x = -2 C is looking good but check it if x = -2 does y = +2 work? yes if x = +8 does 42 work? looks good so C

*April 22, 2016*

**Technology**

Hard to say. If you tried to copy and paste, that does not work here.

*April 22, 2016*

**Precal**

log x + log (x-3) = 1 log (x^2 -3x) = 1 10^log (x^2 -3x) = 10^1 = 10 x^2 -3 x -10 = 0 (x-5)(x+2) = 0 x = +5 or - 2

*April 22, 2016*