Tuesday
February 21, 2017

Posts by Damon

Total # Posts: 29,375

Science
two problems connected only by falling time vertical problem: Vi = initial y velocity = 0 v = Vi - g t h = Hi + Vi t - .5 g t^2 so at ground 0 = 0.6 + 0 - 4.9 t^2 t^2 = 0.6/4.9 t = 0.35 s to fall v at ground = 9.81* 0.35 horizontal velocity = 2.4 until it hits range = 2.4 * .35
February 12, 2017

Algebra
3 a + 9 c = 183 6 a + 13 c = 276 multiply first equation by 2 6 a + 18 c = 366 6 a + 13 c = 276 ---------------- subtract 5 c = 90 c = 18 etc
February 12, 2017

Math
32/8 1*8 = 8 2*8 = 16 3*8 = 24 4*8 = 32 5*8 = 40 6*8 = 48 7*8 = 56 8*8 = 64 9*8 = 72 10*8= 80
February 12, 2017

English
Is that chair related to you? Or is that the stairs groaning like your baby coyote?
February 12, 2017

Science
initial T = 0+273 P V= n R T same n and R so 2P * 2V = n R (4T) 4*273 = 1092 K which is 1092-273 = 819 C
February 12, 2017

physics
in Part A y = Vi t - 4.9 t^2 30 = Vi(2)- 4.9(4) 2 Vi = 49.6 Vi = 24.8 agreed Part B 15 = 24.8 t - 4.9 t^2 4.9 t^2 - 24.8 t + 15 = 0 t = [ 24.8 +/-sqrt(24.8^2-4*4.9*15) ]/9.81 =[24.8+/- 17.9]/9.81 use smaller t for on the way up .702 seconds
February 11, 2017

physics
I am not going to just do these for you in general magnitude = sqrt (xcomponent^2+ycomponent^2) tan angle from x axis = ycomponent/xcomponent) to do A + B say C = (Ax+Bx)i + (Ay+By)j where i and j are unit vectors in x and y directions
February 11, 2017

Physiscs
If it passes through the bar along the axis of the bar, the moment of inertia is small because the mass is close to the axis of rotation. Remember that mR^2 stuff. It is not zero though unless the radius of the bar is zero :) It is in fact a slender solid cylinder and its ...
February 11, 2017

Physics
Trace ray from the top of A and then another from the bottom of A
February 11, 2017

Physics
identical
February 11, 2017

physics
reaches top 3.6/2 or 1.8 seconds after launch at top, v = 0 but v = Vi - g t in meters, seconds g = 9.81 m/s^2 so 0 = Vi -9.81 t 0 = Vi -9.81*1.8 Vi = 17.7 meters/second
February 11, 2017

math
1.02 x = 7150 so x = 7150/1.02
February 11, 2017

maths
2*20 =
February 11, 2017

pre calc
top = L^2 bottom = L^2 4 sides = 4*13L total = 2 L^2 + 52 L
February 10, 2017

algebra
Good ! You are welcome.
February 10, 2017

algebra
no, look below carefully 3.2*10^2 LY ( 5.88*10^12 mi/LY) = 18.8 * 10^14 mi = 1.88 * 10^15 mi
February 10, 2017

easy algebra question, check answer
yes 3*10^1 * 3*10^5 = 9*10^6 because x^a * x^b = x^(a+b)
February 10, 2017

can not help
Since I do not know what it looks like. You can not copy and paste here.
February 10, 2017

Math
4*10 = 40 10 * 10 = 100 so eleven, but the raft only holds ten :)
February 10, 2017

Social Studies
You are welcome.
February 10, 2017

Social Studies
Well, I would have picked A, although I would put it much more strongly. The Soviet Union effectively took absolute control of countries like Poland, Czechoslovakia, Hungary, East Germany ..... Google "Winston Churchill Iron Curtain speech"
February 10, 2017

Ms Sue?
We are volunteers, for the most part teachers, who are happy to help students, but not to do tests for you. Force = rate of change of momentum = d/dt (m v) if m is constant ( no mass change due to exhaust or fast fuel use or what ever) then: F = m dv/dt F = m a where a is ...
February 10, 2017

Physics
40*9.81*.4 = work done power = work /second so P = 40 * 9.81 * .4/.5 = 314 Watts if you used 10 m/s^2 for g you would get C
February 10, 2017

Physics
25 * 200 = v * 900 v = 5.55 so yes, A
February 10, 2017

do not see pictures
If you tried to post diagrams, that does not work here.
February 9, 2017

Science
1 = 10 log P/Po where log is base 10 0.1 = log P/Po 10^.1 = P/Po P/Po = 1.259
February 9, 2017

Math
You are welcome.
February 9, 2017

Math
steps >/= 10,000 - 5,274
February 9, 2017

Physics 202
for rock: T = 2 pi sqrt (L/g) T = 2 pi sqrt (.5/g) for ball Tb = 5 T so 5 T = 2 pi sqrt (Lb/g) =================== 10pi sqrt (.5/g) = 2pi sqrt (Lb/g) 5 sqrt (.5) = sqrt(Lb) 25 (.5) = Lb Lb = 12.5
February 9, 2017

Math
dR/dx = 1500 - 3000*2/(2x+3)^2 if x = 150 dR/dx = 1500 - 6000/303^2 = $1499.93 per unit the point is that you have an initial 1000 setup cost then it is $1500 per unit but that decreases as the number goes up and you train robots
February 9, 2017

maths fractions
1/4 = 3/12 1/3 = 4/12 x/12 - 3/12 = 4/12 x/12 = 7/12
February 9, 2017

20/15 in lowest terms.Express your answer mixed n
sorry 1 1/3
February 9, 2017

20/15 in lowest terms.Express your answer mixed n
divide top and bottom by 5 4/3 = 3/3 + 1/3 = 3+1/3 = 3 1/3
February 9, 2017

Math
6 out of 20 do not like it. 6/20 = 30/100 or 30%
February 9, 2017

mathematical literacy
2 of cement 2 of lime 2*5 = 10 of sand 2 of water
February 9, 2017

history please help! Check my answers!
Flowers are major, and are only in the third choice, so yes, right.
February 9, 2017

math
ah 40,000 (1.07)^2
February 9, 2017

math
h = 9 - (x+3)^2 = 9 - x^2 -6 x - 9 = -x^2 - 6x slope = dh/dx = -2x -6 zero when x = -3 curvature = d^2h/dx^2 = -2 so that is a maximum then what is h? -x^2 - 6 x = -x (x+6) when x = -3 3 (3) = 9 which we could have said in the beginning because x^2 is always + so 9-x^2 is ...
February 9, 2017

PHYSICS
u = 1.12 forever Vi =initial vertical velocity = 0 v = Vi - 9.81 t h = Hi + Vi t - 4.9 t^2 h = 27.8 - 4.9 t^2 0 = 27.8 - 4.9 t^2 so t = sqrt (27.8/4.9) use that t to get horizontal range x = 1.12 t
February 9, 2017

physics
t cos 52 = (24/2)9.81 = 12*9.81
February 9, 2017

History - please check my answers
1. I would include the check on gov power 2. The First amendment is about Congress NOT MAKING A LAW ABRIDGING the right of the people peaceably to assemble. I am not aware of anything about public versus private property in the First Amendment, although there is case law on ...
February 9, 2017

calculus
64 = (4/3)pi R^3 from that find R dV = surface area * dR (easy way :) so dV/dt = 4 pi R^2 dR/dt 20 in^3/min = 4 pi R^2 dR/dt solve for dR/dt
February 9, 2017

Calculus review
arc tan t where t = x^2 so arc tan x^2 (it is how fast the area is changing at the right side of the area, the high limit of t)
February 9, 2017

Geometry
Diameter = 4' radius = 2' = 24 inches Area = pi r^2 = 576 pi in^2
February 9, 2017

Math
r+4 = 2(a+4) or r - 2a = 4 You need to know something more.
February 9, 2017

maths
(5/8)(152) = 5*19 = 95
February 9, 2017

Physics
does the water just stop or continue moving with the child? it it continues moving on the child for an instant, you have 90 kg, not 30
February 9, 2017

Math
Do + Da = 41 Do + 5 = 2(Da+5) 41 - Da + 5 = 2 Da + 10 etc
February 9, 2017

Math
LOL, subtract 3 from the answers to the question above.
February 9, 2017

physics
luckily a right triangle with legs of 3 and 4 has a hypotenuse of 5 so there is no need to use c^2 = a^2 + b^2 to get the magnitude. The cosine of the angle south of west is 3/5 so the angle is 53.13 degrees south of west which is 180 + 53.13 degrees counterclockwise from the ...
February 9, 2017

physics
west = 2.5 km south = 10 km magnitude = sqrt(6.25 +100) tan of angle south of west = 10/2.5 = 4 angle south of west = 76 degrees south of west
February 9, 2017

Math - Derivatives
dy/dx = x^3 +2x^2 -5x +6 = 12 x^3 + 2 x^2 - 5x -6 = 0 x = -3 , -1 , +2 http://www.wolframalpha.com/widgets/view.jsp?id=b858339e64fa997454dd12f77cb1ece1
February 9, 2017

physics
32 s more,
February 8, 2017

Math 8th grade
well six one hours plus 2 half hours = 7 hours
February 8, 2017

Algebra
.5 D + 1 B </= 6
February 8, 2017

Math
T = L + 19 T + 4 = 2 (L+4) =================== L+19 + 4 = 2 L + 8 L = 15 T = 34
February 8, 2017

Oh maybe it means
does not do 40 for the whole 20 sec, but only for 20 - 4 = 16 s so 100 + 40*16 = 640 + 80 = 820 ..... not a choice though.
February 8, 2017

physics
The trick is to use average speed for a time of constant acceleration v = Vi + a t Vf = final v = Vi + a t Vf -Vi = a t so a = (Vf -Vi)/t d = Vi t + .5 a t^2 d = Vi t + .5 (Vf-Vi)t^2/t d = Vi t -.5 Vi t + .5 Vf t d = .5(Vi+Vf) t BUT .5(Vi+Vf) IS the average speed during ...
February 8, 2017

physics
average 20 for first 5 so 100 m go 40 for 20 s so 800 more now brake average 20 for 4 = 80 980 so I agree
February 8, 2017

math
What does full mean? Multiply by 3 every day? That is called geometric sequence http://www.mathsisfun.com/algebra/sequences-sums-geometric.html Say A is amount on day 1 then on day 12 you have A(3)^11 and on day 4 you have A(3)^3 3^11/3^3 = 3^8 = 6561 so you have 6561 times as...
February 8, 2017

World history
LOL, I guess you would not have a list of answer choices for this. In fact this requires at least a bookcase full of history texts and research papers and I am not sure how to do anything but point you to a few web sites. I guess start with the rivers (Tigris and Euphrates) ...
February 8, 2017

Math
-3 / (1/2) = -3(2/1) = -6/1 = -6
February 8, 2017

Maths
common multiple 5 2*2*2 2*2*3 need 5 2 2 2 3 120
February 8, 2017

Math
lol, square has at least 4 how many does a circle have ? ;)
February 8, 2017

Maths
alpha^.5 = [b +sqrt(b^2-4c)]/2 beta^.5 = [b -sqrt(b^2-4c)]/2 alpha =(1/4) [ b^2 +2bsqrt(b^2-4c)+b^2-4c] beta =(1/4) [ b^2 -2bsqrt(b^2-4c)+b^2-4c] alpha + beta = (1/4) [4 b^2 -8 c] = b^2 - 2 c etc ....
February 8, 2017

physics
10^4 km = 10^7 meters !!!! well the force on 1kg is the value of g there :) F = G * 1 * M /R^2 F =6.67*10^-11 * 6 *10^6 /(16*10^14) I think you probably have a typo
February 8, 2017

Math
-5 = -a+b-c dy/dx = 3 a x^2 + 2 b x + c = 4 at x = -1 so 3a - 2b + c = 4 d^2y/dx^2 = 0 = 6ax +2b = -6a+2b so b = 3 a 3 a -6a + c = 4 -5 = -a +3a -c -3a + c = +4 +2a - c = -5 ------------ 5 a = 9 etc check my arithmetic
February 8, 2017

Math Independent & Dependent.
the cost depends on how many c = 7 s http://nces.ed.gov/nceskids/help/user_guide/graph/variables.asp
February 8, 2017

Calculus unit review
draw a graph point A is (1/11) f(5) = f(1) + integral 1 to 5 (f' dx) = 11 + 9 = 20 or just say integral from 1 to 5 of (dy/dx) dx = y(5)-y(1)
February 8, 2017

Math
before x students 5x/8 boys and 3x/8 girls so later 3x/8 + 6 = 5x/8 3 x + 48 = 5 x 2 x = 48 so x = 24 students before x+6 = 30 after 6 girls arrived
February 8, 2017

how many minutes
hours = minutes/60 speed = 63 miles/those hours
February 7, 2017

math
1.20 x
February 7, 2017

Math
(7/8)(16/1) = 7*16/8 = 7*2 = 14
February 7, 2017

Math
hat is zero at -3, -3 , 2 ,2 , -5 the double roots mean the curve just touches the axis at: -3 and +2 when x is big positive, it is big positive when x is big negative it is big negative y = 180 when x = 0 so starts at lower left crosses x axis at x=-5 goes up then dips down ...
February 7, 2017

Physics
total energy is constant until it hits the ground. Potential turns to kinetic. m g h = 8 * 9.81 * 100 Joules
February 7, 2017

History
I am inclined to agree with you. See: http://en.wikipedia.org/wiki/Freedmen's_Bureau_bills although in practice it turned out more like B and even that was undermined by the KKK etc.
February 7, 2017

Math - limits
in radians sin t --> t + t^2/2! -t^3/3!..... so in radians sin t/t --->1 as t--->0 however we are doing degrees do t degrees which is (pi t/180) rad so we have sin (pi t/180) /t which becomes (pi t/180 +(pi t/180)^2/2 ... divided by t ----> pi/180 as t--->0...
February 7, 2017

Math
15/12 = 5/4
February 7, 2017

Math
agree
February 7, 2017

Math
1 / 3
February 7, 2017

math
Smith: 1 teen drinks 2/3 case / 5 weeks so 1 teen drinks 2/15 case / 1 week ===============================Jones 1 teen drinks 5/6 case / 4 weeks so 1 teen drinks 5/24 case / 1 week ======================== smith 2/15 jones 5/24 which is bigger? 15 = 3*5 24 = 3 * 8 3*8*5 = 120...
February 7, 2017

math
Once again 192 - 150 = 42 NOT 142
February 7, 2017

Social studies
ok :) Then I agree with you.
February 7, 2017

spelling ?
mass crowding maybe? If so yes.
February 7, 2017

error
192=k+54c............................. (1) 150=k+14c. ........................... (2) subtract (1) from (2) 142=40c ============================= whoops 42 not 142
February 7, 2017

physics
mg + mv^2/r = 1000 Newtons g = 9.81 m/s^2 v = 7.4 m/s r = 11.2 m solve for m
February 7, 2017

statistics
http://davidmlane.com/hyperstat/z_table.html
February 7, 2017

Physics
yes, true power = V i but V = i R so Power = i^2 R = V^2/R Joules per second or "Watts" Energy (or heat) = Power * time so indeed H = i^2 R t = V^2/R Joules Now how much heat do we need? H = mass * specific heat * change in temp H = 0.5 * 4.19*10^3 * 70 Joules so in ...
February 7, 2017

Science
x = sin (2 pi t/T) 1/2 = sin (2 pi t/24) 2 pi t/24 = pi/6 because pi/3 radians= 30 degrees and sin pi/6 = 1/2 t/12 = 1/6 t = 2
February 7, 2017

Math
L = 31.5 w = (4/7)31.5 = 18 p = 2 * 31.5 + 2 * 18 A = 31.5 * 18
February 7, 2017

Science
force = change in momentum/time 10 N = 10 kg *V / 10 s V = 10 m/s ============= or F = m a 10 = 10 a a = 1 m/s^2 v = a t v = 1*10 = 10 m/s
February 7, 2017

physics
v = a t 100 m/s = a ( 5 s) s = 20 m/s^2
February 7, 2017

Physics
By the way, GOOGLE Archimedes
February 6, 2017

Physics
weight in water = WW Newtons weight in air = WA Newtons mass = WA/9.81 kilograms (if your scale reads in kilograms, multiply by 9.81 m/s^2 on earth to get Newtons) difference = WA-WW = buoyant force = volume*density of water * 9.81 density of water = 1,000 kg/m^3 so difference...
February 6, 2017

algebra
typo maybe?
February 6, 2017

algebra
you have 0k so you can not solve for k
February 6, 2017

physics
a = dv/dt = 6.24 so v = constant + 6.24 t at t = 0, v = Vi so v = Vi + 6.24 t 9.36 = Vi + 6.24 * .44
February 6, 2017

Math
think ! 1. It starts in 1990 at 1,000,000 2. it DECREASES and you meant to the POWER t, not times t a k^t not a k t to check at 2010, t = 20 years y = 1,000,000* .98^20 ?
February 6, 2017

order does matter, typo by me
Write the number of permutations in factorial form, then simplify. How many differnet ways can you and four of your friends sit in the backseat of a limousine? A. 4!;24 b.4!120 C.5! 120 D. 5! 720 There are 5 of you. Order does matter so permutations of 5 taken 5 at a time 5! =...
February 6, 2017

PLLZ!PLLZ help with math quick!!!!!
Ariel wants to choose 5 players for her basketball team. There are 7 players to choose from.How many different teams can Ariel make? A. 21 B.32 c.42 D.56 =============================== combinations in grade seven? C(n,r) = n!/[r!(n-r)!] = 7!/[5!(2!)] = 7*6/2 =21...
February 6, 2017

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