Wednesday

January 18, 2017
Total # Posts: 28,788

**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*

**Math**

A = x*y 32 = x+2y x = 32-2y A = (32-2y)y = 32y-2y^2 or y^2-16y = -A/2 you did not say if you are in algebra or calculus so I will do it the algebra way by completing the square y^2 -16y + (16/2)^2 = -A/2 + 64 (y-8)^2 = -(1/2)(A-128) y = 8 x = 16 and the area is 128 ft^2

*January 9, 2017*

**please show your attempts**

We are teachers. We do not do tessts for people.

*January 9, 2017*

**physics**

+250 :) weight = m g = 55*9.8 = 539 Newtons That is the normal force on the floor Max friction = .56*539 = 302 N

*January 8, 2017*

**physics**

weight = w = m g normal force = m g cos theta ratio = cos theta so cos 17 and cos 30

*January 8, 2017*

**calculus**

Oh, intercepts y = x^3-6x^2 0 = x^2 (x-6) bounced off x axis at x = 0 crossed x axis at x = 6

*January 8, 2017*

**calculus**

slope = 3 x^2 -12 x =3 x (x-4) second derivative (curvature) = 6 x - 12 so the slope is 0 at x = 0 and at x = 4 at x = 0 is that a min or a max or in inflection point? second derivative = -12 That is a maximum, starts down from there at x = 4 is that a min or a max or an ...

*January 8, 2017*

**Chemistry**

CuCO3 = 64+12+48 g/mol = 124 g 31/124 = .25 mol CO2 = 12+32 = 44 g/mol so 11 g for .25 mol for CuO, subtract:) 31-11 = 20 grams check: CuO = 64+16 = 80 g/mol .25*80 = 20 grams sure enough

*January 8, 2017*

**calculus**

two negative numbers can not add to +1

*January 8, 2017*

**calculus**

b.f(x)=x^3=x-4 Typo, makes no sense c. f(2)=8 f(-1)=-1 so 9/3 average slope =3 f' =3x^2 3 x^2 =3 x= sqrt(1) which is 1 !!!! but also -1 d f(4) = 2 f(0) = 0 so slope = 2/4 = 1/2 f' = (1/2)x^-1/2 = 1/2 x = 1 again

*January 8, 2017*

**Math**

a + b + c = 975 a - x = 12 b - x = 345 c - x = 126 --------------add a+b+c -3 x = 483 so 975 - 3 x = 483 3 x = 492 x = 164

*January 8, 2017*

**physics**

mapple Vapple +mweath*0 = (mapple+mearth) V V = Vapple (mapple)/(mapple+mearth) so yes mapple/(mapple+mearth) is not very big it might be kind of hard to measure :)

*January 8, 2017*

**physics**

The earth moves under your feet (but just a little).

*January 8, 2017*

**Math**

L(1-cosT) = 1/3 foot sin T = 4 feet/L so L sin T =4 1-cosT = 1/3L L sinT = 4 cosT = (3L-1)/3L so cos^2T = (9L^2 -6L+1)/9L^2 so 1-cos^2T = (6L-1)/9L^2 which is sin^2 T but sin^2T =16/L^2 so 16/L^2 = (6L-1)/9L^2 144 = 6L-1 6L = 145 L = 24.2 feet check my arithmetic!

*January 8, 2017*

**calculus**

dV = surface area * dr so dr/dt = dV/dt/(4 pi r^2) dr/dt = 2 /(4 pi *64)

*January 8, 2017*

**math**

well, you just said math, not calculus, which is why I completed the square to find the vertex of the parabola in the other problem. 3 4 5 triangle x = 4 y = 3 hypotenuse = 5 dy/dt = -2 ============================= x^2 + y^2 = 25 2 x dx/dt + 2 y dy/dt = 0 dx/dy = -(y/x)dy/dt...

*January 8, 2017*

**math**

r = x (1000-2x) r = 1000 x -2 x^2 2 x^2 -1000 x = -r x^2 - 500 x = -(1/2)r x^2 -500 x + 250^2 = -(1/2)r + 250^2 (x-250)^2 = -(1/2)(r-2(250)^2 ) x = 250 r = 2*250^2 = 125,000

*January 8, 2017*

**Algebra**

[ (x/3) -5 ] 7 = 28 (x/3) -5 = 4 x/3 = 9 x = 27

*January 8, 2017*

**calculus**

check end points f(-2) = -2+8 = 6 f(2) = 2-8 = -6 now find where derivative is zero f' = 1 -3x^2 = 0 when x = 1/sqrt3 or x = -1/sqrt3 if x = 1/sqrt 3 f = 1/sqrt3 -1/3sqrt3 =(2/3sqrt3) if x = -1/sqrt3 f = -1/sqrt3 +1/3sqrt 3 = -(2/3sqrt3) so the max and min are at the end ...

*January 8, 2017*

**calculus**

Well, try one of them. function is continuous and differentiable from 1 to 3 (note not at zero) f(3) = 3-1/3 = 8/3 f(1) = 0 [f(3)-f(1)]/(3-1) = 4/3 so where is the derivative 4/3? f'(x) = 1 + 1/x^2 where does 1+1/x^2 = 4/3 ? 1/x^2 = 1/3 x = sqrt 3 yes, that is between x = ...

*January 8, 2017*

**Physics**

pm=1.6gcm^-3 nonsense V = 40 cm^3 so mass = 20 + 40 * density of Hg which is not 1.6 g/cm^3

*January 8, 2017*

**Math**

original = p cents / pizza 10 p = total cost 9(p+60) = same total cost so 10 p = 9(p+60) p =540 cents = 5.40 per pizza so $54

*January 7, 2017*

**math**

n = original 1.2 n = before 300 .2 * 1.2 n = 300 so 1.2 n = 1500 n = 1250 books originally ===================== check ===================== 1.2 * 1250 = 1500 +300 = 1800 1.2*1.2*1250 = 1800 sure enough

*January 7, 2017*

**Algebra 1**

x = [2p+/-sqrt(4p^2+32p^2) ]2 = [2 p + sqrt(36 p^2) ]/2 = [2 p + 6 p ]/2 = 4 p

*January 7, 2017*

**Math**

(43/2)(3/4)= 129/8 left after tacos (2/3)(129/8) used for burgers times 4 for number of 1/4 lb burgers 4(2/3)(129/8) = 129/3 = 43 burgers

*January 7, 2017*

**another subtraction error**

360 - 12 = 348 348 = 23 t -23t/2 696 = 23 t t = 30.3 a = 23/30.3 = .759 m/s^2

*January 7, 2017*

**Physics**

freight train goes 6 t our train goes 6t+360 Vi = 29 Vf = 6 a assumed negative v = Vi - a t 6 = 29 - a t a t = 23 d = 6t+360 = 29t-(1/2)a t^2 360 = 23 t -(1/2)(23 t) 720 = 23 t t = 31.3 seconds to crash a = .74 whoops, forgot the .4 seconds to react we go 14.5 m he goes 2.4 m ...

*January 7, 2017*

**Algebra 1**

You are welcome.

*January 7, 2017*

**Algebra 1**

n + n+1 + n+2 + n+3 + n+4 = 5 n + 10 so (5n+10)/5 = 13 5n+10 = 65 5 n = 55 n = 11 so 11 , 12, 13 , 14, 15 old sum was 65 new sum is 53 difference is 12 so 12

*January 7, 2017*

**Physics**

Not really. I bet you have heard the word "Impulse" that is force * time which is change of momentum F = m a = m dv/dt so F dt = m dv = "impulse" but m dv is change in m v and m v is "momentum therefore F * time = change in momentum = impulse

*January 7, 2017*