Wednesday
January 18, 2017

Posts by Damon

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

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