Saturday

February 25, 2017
Total # Posts: 29,414

**algebra**

7/3 = 2 1/3 or 2.33333.......

*January 21, 2017*

**algebra**

0.164*188 = 30.8

*January 21, 2017*

**Physics**

h = 20 + .4 t - 4.9 t^2 solve for t when h = 0 just like the problem you posted below this one. also the speed when it hits the ground is the same method.

*January 21, 2017*

**Physics**

h = 1.5 + 2.5 t -4.9 t^2 when is h = 0? solve quadratic for t 4.9 t^2 -2.5 t - 1.5 = 0 you could use http://www.math.com/students/calculators/source/quadratic.htm Note, quadratics have two solutions of course. In this problem if you get a neagative time, that is how long ago ...

*January 21, 2017*

**Physics**

d = 13.9 * .6 + (13.9/2)t because average speed during deacceleration = half the original speed time to stop during acceleration is t: v = Vi + a t in general so 0 = 13.9 - 3 t t = 13.9/3 so in the end d=13.9*.6 + (13.9/2)(13.9/3) part b will you go 35+9.5 meters in time? what...

*January 21, 2017*

**Physics**

a)assume you mean Vx=1.4t^2+1.1t v = 1.4(16) + 1.1(4) b) change in velocity = answer to part a since velocity at t = 0 was 0 so divide a the answer to part a by 4 seconds

*January 21, 2017*

**Oh, use Reiny reply**

I did not see the reversal of direction

*January 21, 2017*

**Physics (typo?)**

30 min = .5 h 10 min = 1/6 h 20 min = 1/3 h ================= d = 140*.5 + 90/6 + 90/3 (it went 90 for a total of 1/2hour???? typo I bet) average speed = d /total time the way you wrote it the total time is one hour, but I doubt it.

*January 21, 2017*

**science doppler to and fro**

what frequency does the blood hear? for observer toward source: f' = f (v+Vobserver)/v f' =6.113*10^6(1570+.3979)/1570 calculate f' the blood particle serves as a transponder sending back a signal at that f' now the source is moving toward the observer f"...

*January 21, 2017*

**Physics**

for speed divide the distance by the time for velocity divide the DISPLACEMENT by the time displacement is a vector with x y and perhaps z components. All the way around a track is a Distance of 2 pi r BUT a displacement of ZERO

*January 21, 2017*

**science chemistry**

Particles maintain their distance and orientation to other particles in the solid state and only vibrate a little in place so the shape and volume of a lead block does not change (much:). In the liquid state, the particles maintain their distance but not orientation so the ...

*January 21, 2017*

**Physics 11 question pls urgent HELP!!!!!**

No The CHANGE in speed is acceleration times time 12.5 * 3.25 That is all you need The initial speed is not relevant. momentum change = mass*change in velocity = 1205*12.5*3.25 kg m/s

*January 21, 2017*

**math**

the whole thing is 14 m by 8 m so the walkway area is 14*8 - 12*6

*January 20, 2017*

**physics**

here.... +small ...... -big x ......... 0.......... 4.35 just using distances without regard to sign to get equal field magnitudes 1.90/x^2 = 3.61/(x+4.35)^2 solve for x, note it has to be - (left of origin) 3.61 x^2 = 1.9(x^2 +8.7 x+18.9) 3.61x^2 = 1.9x^2 + 16.5x + 35.9 1.71x...

*January 20, 2017*

**Science**

The birds reproduce in six months? The birds did not use the O2 in the water directly. Even cormorants breathe air above the water :) However the fish did. I think there might possibly be more fish in 6 months but doubt if the birds would react that quickly.

*January 19, 2017*

**oic**

oh, did not notice the "undefined" line is x = 2 vertical line

*January 19, 2017*

**Algebra**

slope = (9-2)/(x-2) =7/(x-2)

*January 19, 2017*

**Algebra**

LOL - three ways to get at that same parabola

*January 19, 2017*

**Algebra**

that is a parabola, where is the vertex? 16 t^2 - 96 t = -h +256 t^2 - 6 t = (1/16)(-h + 256) t^2 - 6 t + (6/2)^2 = (1/16)(-h + 256) + 9 (t-3)^2 = (1/16)(-h + 256) +(1/16)(144) (t-3)^2 = -(1/16)(h-400) vertex at 3 seconds and h =400 ft

*January 19, 2017*

**math please help**

so 12.5/100 = 125/1000 = (5*25)/(40*25) =5/40 =1/8

*January 19, 2017*

**Further mathematics**

say 15 N along x axis and 10 N 60 deg above -x axis x force = 15 - 10 cos 60 = 10 y force = 10 sin 60 = 8.66 magnitude = sqrt(100+8.66^2) tan angle above +x axis = .866

*January 19, 2017*

**Maths lit**

32*0.794 Kg

*January 19, 2017*

**Math**

r = 0.045 Ai = 500 dA/dt = Ar dA/A = r dt ln A = r t A = Ai e^rt 2500 = 500 e^.045 t 5 = e^.045 t ln 5 = .045 t so t = ln 5/.045 =1.61/.045 = 35.8 years

*January 19, 2017*

**US History**

I am no expert but in this period of westward expansion of cattle range after the Civil War I think both c and d are appropriate answers.

*January 19, 2017*

**MATH**

11 - G

*January 18, 2017*

**math**

(5/20)100 = 25%

*January 18, 2017*

**sorry, yes**

8C4 = 8!/[4!(4!)] = 8*7*6*5/(4*3*2) = 70 so 15*70 = 1050

*January 18, 2017*

**MATH HELP**

2 out of 6 administrators 4 out of 6 others combinations of 6 taken 2 at a time = 6!/[ 2!(4!)] =6*5/2 = 15 combinations of administrators combinations of 6 taken 4 at a time = 6!/[ 4!(2!)] = 6*5/2 = 15 combinations of faculty and students so 15*15 = 225

*January 18, 2017*

**Partial Sums and finding a certain term**

S3-S2 = term 3 S3 = 13/17 S2 = 8/12 maybe 13/17 - 8/12 ??? about .098

*January 18, 2017*

**Algebra**

-11 x^5 +4x +8x^3 -13x -2 +7x^3 -11x^5 +15 x^3 -9x -2

*January 18, 2017*

**Triangles math**

fraction = percent /100 2*0.5 and 3*0.5 2*3 and 3*3 2*5 and 3*5

*January 18, 2017*

**math**

2/5 of 5/12 = 1/6

*January 17, 2017*

**math**

2/3 left after pie 3/8 of that left 2/3 * 3/8 = 1/4 really the same as your problem above

*January 17, 2017*

**social studies**

and you are right.

*January 17, 2017*

**physics**

energy = q V = 16 q so (1/2) m v^2 = 16 q

*January 17, 2017*

**physics**

g sin theta = constant = your gravitational acceleration for this problem, all it ourg m a = -kx + m ourg = m d^2x/dt^2 x = Xi + xh sin 2 pi t/T Xi is our equilibrium x when a = 0 Xi = m ourg/k now if harmonic then xh is our harmonic motion x do it separate as added to Xi x = ...

*January 17, 2017*

**Trigonometry**

sqrt(49+9) = sqrt(58) =7.61 tan angle above -x axis = 3/7 A = .405 radians *180/pi = 23.2 deg so angle counterclockwise from x axis = 180-23.2

*January 17, 2017*

**LOL - hardly**

If I knew this was for a test I would not be doing it.

*January 17, 2017*

**Math (help if you know the full test)**

5/16 = .3125 which is 31.25 %

*January 17, 2017*

**science(physics)**

Try a turn, look at Ac = v^2/R needs side force from road at bottom moment about CG is balanced by light force up on inner tires and heavy force up on outer tires. The higher the CG, the longer that moment arm. When v^2/r is high enough, inner tires lift off road.

*January 17, 2017*

**math**

Na = .05*10 + .02*5 = .6 percent NaCl = .6/15 *100 = 4% =.04 .04/15ml = 40/15 grams/liter so what is 40 grams of NaCl in mols? 40g/58.44 g/mol = .684 M

*January 17, 2017*

**physics**

impulse = force * time = change of momentum the key word is "quick"

*January 17, 2017*

**maths**

w = 2h+3 total w = w+5 total h = h+5 A = (w+5)(h+5) = w h + 5w + 5h + 25 = (2h+3)h + 5(2h+3) + 5h +25 = 2h^2 +3h +10h +15 +5h + 25 = 2h^2 + 18h + 40 = 2(h^2 + 9 h + 20) =2(h+4)(h+5)

*January 17, 2017*

**Maths**

(3km/60min)20min = 1 km

*January 17, 2017*

**Algebra 2**

combinations of 18 taken 10 at a time = 18!/[ 10!(18-10)!] = 18*17*16*15*14*13*12*11/ (8*7*6*5*4*3*2) = 17*16*15*14*13*12*11/(8*7*5*4*2) = 17*15*14*13*12*11/(7*5*4) = 17*3*2*13*3*11 = 43,758

*January 17, 2017*

**Algebra 2**

combinations of 6 taken four at a time same method as your other problem 6*5/2 = 15

*January 17, 2017*

**Algebra 2**

well, around four times :) d = k v^2 49 = k (900) k = 49/900 d = (49/900)(65)^2 = 230 feet

*January 17, 2017*

**Maths**

h/5 = 20/(25+5) h = 100/30 = 10/3 = 3.33 ft

*January 17, 2017*

**Physics**

average speed = (8+0)/2 = 4 m/s so t = .30 meters/4 meters/s =.3/4 s Force * time = change of momentum or impulse F(.3/4) = .5 * 8 F = (5/3)(32) = 53.3 Newtons

*January 17, 2017*

**history**

One factor: Rotten governments in the Byzantine Empire, Persia, Mesopotamia, the Levant, Egypt, North Africa, Spain and much of Asia. Serious resistance resulted when they ran into the Franks in France.

*January 16, 2017*

**math**

about 780 http://davidmlane.com/hyperstat/z_table.html

*January 16, 2017*

**Algebra 6**

2 y + 1 x + 2 = 1 x + 2 y + 2 0 = 0 true for any x and y

*January 16, 2017*

**Algebra 2**

1<11 and 1>-3 :) yes a

*January 16, 2017*

**math**

10.8/3 = 3.6 (10.8-5.4)/1 = 5.4 (24.6-10.8)/2 = 6.9 (17.4-10.8)/1 = 6.6 (17.4-5.4)/2 = 6

*January 16, 2017*

**geo**

Area = 30m^2=30*10^4 cm^2 30*10^4 * 4 =120*10^4 cm^3/week there are 1000 cm^3/liter so 120*10^1 = 1200 liters

*January 16, 2017*

**maths/physics help**

Inew = .4*I Inew * omega new = I omega omega new = (I/.4I) * 1 rev/s omega new = 1/.4 = 2.5 rev/s

*January 16, 2017*

**American History**

The American colonies developed during turbulent times in England. The settlers in Virginia were for the most part "cavaliers", followers of the royal family. Other colonies such as in New England and the mid Atlantic were of Cromwellian mindset. The British ...

*January 15, 2017*

**value**

at time 0 30,000 at time 1 1.045*30,000+8,000 = 39,350 at time 2 1.045*39350 +8,000 = 49,120.75

*January 15, 2017*

**Math**

54/3 = 18 w/h 18 * 6 = 108 w

*January 15, 2017*

**statistics**

k(1+2+3+4+5) = 1 k = 1/15 p(3) = 3/15 p(4) = 4/15 p(5) = 5/15 so p (x>/=3) = 12/15 = 4/5 etc

*January 15, 2017*

**math**

n(n-2) = 24 n^2 - 2 n - 24 = 0 (n-6)(n+4) = 0 n = 6

*January 15, 2017*

**science**

I guess it is 4 m high?? if so the water is 2 m deep the pressure is one atmosphere plus 1000 kg/m^3 * 9.81 m/s^2 * 2 m newtons per m^2 or Pascals

*January 15, 2017*

**maths**

a21 = a1 + 20 d a10 = a1 + 9 d

*January 15, 2017*

**science**

Two H+ ions per molecule so I suppose 2 * 0.08 = 0.16

*January 15, 2017*

**Physics**

.075 v = (.075+2.000)1.5 so v = 3/.075 = 40 m/s approximately

*January 15, 2017*

**maths**

42(3/7) = 18

*January 15, 2017*

**math**

29 students do something 16-x do G only 18-x do H only x do both 16-x + 18-x + x = 29 34 -x = 29 x = 5

*January 15, 2017*

**Math**

150 * .05 pounds

*January 15, 2017*

**Physisc**

a = F/m = 120/12 = 10 m/s^2 v = Vi + a t v = 4 + 10 t by the way for distance x = Xi + Vi t + (1/2)a t^2 = 0 + 4 t + 5 t^2

*January 14, 2017*

**Science, pls help Ms. Sue!!!!!!!**

The word "electrolysis" gives it away John1.

*January 14, 2017*

**water--> Hydrogen and Oxygen**

2H2O ---> O2 + 2H2 That is a chemical reaction

*January 14, 2017*

**Intro to stats**

It is uniform? Then between 2 and 18 is 16/23 = .69565

*January 14, 2017*

**calculation error**

t = 2.83 seconds v = 2.5 * 2.83 = 7.07 m/s

*January 14, 2017*

**Physics**

Oh, I see, the force is forever a = F/m = 5/2 = 2.5 m/s^2 10 = (1/2) a t^2 20 = 2.5 t^2 t = 6.93 seconds V = a t = 2.5 *6.93 = 17.3 m/s

*January 14, 2017*

**for how long?**

How long was the force in contact with the ball? Force * time = change in momentum = m v

*January 14, 2017*

**Math**

.015 mols/liter * .01 liter = .15 mols = .00015*332 = .0498 agree

*January 14, 2017*

**Maths**

http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html a3 = a1 + 2 d = 90 a11 = a1 + 10 d = 50 -----------------------subtract a3-a11 = 0 -8 d = 40 so d = -5

*January 14, 2017*

**physic**

up for time t then down for time t (parabola) u = 100 cos 45 forever Vi = 100 sin 45 at start v = Vi - g t at top v = 0 so at top t = Vi/g = 100 sin 45 / 9.81 in the air for time = 2 t so range = 2 t u = 2 t (100 cos 45)

*January 14, 2017*

**Calc**

f = ln g df/dx = df/dg * dg/dx we were given dg/dx what is df/dg ? df/dg = d ln g / dg = 1/g so df/dx = (1/g)tan 2/(1+x^2) I think you mean = (1/5)tan 2/2 = (1/4) tan one radian or 180/pi deg = (1/5)(1.055741 ) = .31148 so agree

*January 14, 2017*

**physics**

do horizontal and vertical separately I assume j is up v = 13 - 9.81 t y = 0 + 13 t -4.9 t^2 If y is negative, it dug a hole :) and x = 12 t so d = 12 t i + (13t-4.9t^2) j

*January 13, 2017*

**math**

we have 9 * 300 = 2700 bee months of honey we now have 450 bees 2700 bee months / 450 bees = 6 months

*January 13, 2017*

**physics**

The trick here is guessing the drag coefficient of the raindrop shape. See: http://home2.fvcc.edu/~dhicketh/DiffEqns/Spring11projects/Ben_Lynch_Gavin_Lommatsch/DiffEqProject/DiffEqProjectGavinBen.pdf It is a function of Reynolds number even if the shape is spherical. However ...

*January 13, 2017*

**mathematics**

original, then difference, then difference of difference 2 ...... 3 5 ........... 2 .......5 10 .......... 2 .......7 17 ...........2 .......9 26 constant difference of differences is parabola well, y = x^2 + 1 works an = n^2+1

*January 13, 2017*

**What?**

Check for typos please. If you mean merged, same total volume, then with the same height, the base areas add up to the original. pi R^2 = pi r1^2 + pi r2^2 R2 = sqrt( r1^2 + r2^2)

*January 13, 2017*

**maths**

of course the area of ABC = (1/2)(3*4) = 6 :) also (1/2)(AD)(5) = 6 AD = 12/5 = 2.4 cm

*January 13, 2017*

**The cay is the book**

C is the only choice that indicates determination.

*January 13, 2017*

**Physics**

how long does it take to get from 100 to 30? v = vi + a t 30 = 100 - 4 t 4 t = 70 t = 17.5 s how far did we go? average speed = 130/2 = 65 65*17.5 = 1137.5 ft how far did the freight go? 30 * 17.5 = 525 525 + 600 = 1125 ft CRASH for part b x1 = 100 t - 2 t^2 x2 = 600 + 30 t ...

*January 13, 2017*

**math**

No, slant height is hypotenuse of triangle where altitude is one leg and half the base is the other.

*January 12, 2017*

**Computing**

n = 1 10 output = n*n print output n = n+1 if n = 6 quit otherwise go back up to 10

*January 12, 2017*

**maths**

3.14159.... is between 3 and 4

*January 12, 2017*

**physics**

I guess he is JUST prevented from slipping normal force = m g cos 43 force down slope = m g sin 43 so m g sin 43 = 520

*January 11, 2017*

**physics**

The same. If there is no acceleration there is no change in force (ignoring friction).

*January 11, 2017*

**Direction?**

Forces are vectors. If they are equal in magnitude but opposite in direction, they add to zero. If both in the same direction, then twice. If in between, then in between.

*January 11, 2017*

**physics**

Find the resultant of the two perpendicular forces |F| = sqrt (76.5^2+46.3^2) tan A = 76.5/46.3 where A is angle north of west our force is equal and opposite same |F| same angle but south of east

*January 11, 2017*

**math**

c = 3(c+3) -3(c-3) c = 3 c + 9 - 3 c + 9 c = 18

*January 10, 2017*

**pure physics**

Weight of water displaced = .25-.20 = .05 N which is the force up on the stone from the water.

*January 10, 2017*

**error**

2 a - 62 = 12 2 a = 74 !!!!! a = 37 b = 25 same answer anyway

*January 9, 2017*

**Algebra**

a+b = 62 so b = (62-a) a - b = 12 a -(62-a) = 12 2 a - 62 = 12 2 a = 50 a = 25 b = 62-25 = 37

*January 9, 2017*

**Math**

24/2.5 = 9.6 so 9 strips with a little left over but not really because some is lost in the kerf (the width of the blade)

*January 9, 2017*

**Math, Physics**

F = m g g = gsurface * Rearth^2/R^2 = 9.81 * Rearth^2/(Rearth+401500)^2

*January 9, 2017*