# Posts by Damon

Total # Posts: 29,984

**calculus**

I am a physicist so call your y "v", velocity and your x is "t" d = integral v dt d is integral from 1 to 5 of (t^2 -9) dt = t^3/3 - 9t at 5 - at 1 at 5 it is 125/3 - 45 at 1 it is 1/3 - 9 -------------------subtract 124/3 - 36

**Stat**

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

**physics**

forget cm, doing seconds and meters - SCI units Pe = (1/2) k |x|^2 Ke = (1/2) m |v|^2 so for Ke = 1/2 Pe m |v|^2 = .5 k |x|^2 but ?^2 = k/m so |v|^2 = .5 ?^2 |x|^2 At our spots [A ? cos ?t]^2 = .5?^2[A sin ?t]^2 A^2 ?^2 cos^2?t = .5?^2 A^2sin^2wt cos^2 ?t = .5 sin^2 ?t cos^2 ?...

**p**

I already did one like this for you.

**physics**

.35 meters in half a period, T/2 2 A = .35 x = A sin 2 pi f t x = A sin (2 pi t/T) max at T/4 min at 3T/4 3T/4 - T/4 = time between max and min = T/2 so 0.30 m/s = 0.35 m /(T/2)s T/2 = 0.35/.3 T = 7/3 seconds w = ang freq = 2pi/T = 6 pi/7 max a = w^2 A = (6pi/7)^2(.35/2) max v...

**physics**

I took this course in 1955 and no longer need practice. You are asking basically the same question over and over. I am happy to help but have done enough of them for you. since it is not extended at the start use y= A cos 2 pi t/T which is A at t = 0 and hits the lowest point...

**physics**

Hey, you do some now !

**Social Studies**

This is much more how I remember it: http://www.georgiaencyclopedia.org/articles/government-politics/worcester-v-georgia-1832

**Social Studies**

That decision I just looked up is not how I remember it in fact. I thought the Supreme Court sided with the tribes and Andrew Jackson kicked the tribes west anyway. Yes, what the above says is that white settlers can not be prohibited from trespassing on native property.

**Social Studies**

from Google: 515 (1832), was a case in which the United States Supreme Court vacated the conviction of Samuel Worcester and held that the Georgia criminal statute that prohibited non-Native Americans from being present on Native American lands without a license from the state ...

**physics**

sqrt (37^2+44^2) = 57.49 = 57 meters tan angle = 44/-37 angle = -50 x is - and y is + so second quadrant 180 - 50 = 130

**Geometry**

another one?

**Math**

e^0.018t = 20/12 .018 t = ln (20/12) = .511 t = 28.4 years

**physics**

ke = (1/2)(5.4) (6.2)^2 stops so all ke converted to U U = m g h = ke from first part 5.4 (9.81) h = answer from part 1

**physics**

d = (1/2) a t^2 8 = .5 a (16) so a = 1 m/s^2 v = a t = 1 (4) = 4 m/s or use head like this average speed = 8 m/4s = 2 m/s begin speed is zero so final speed = twice average speed = 2*2 = 4 m/s

**math algebra**

log x^n = n log x so you have log x (1+2+3+4 ...120) so log x times arithmetic sequence sum with a = 1, d = 1 n from 1 to 120 see http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html

**Algebra**

|3y+4| means absolute value of 3y+4 -| means nothing to me.

**huh**

typo ?

**physics**

1 m^2 = 10,000 cm^2 20 * 10,000 = 200,000 N/m^2 400 cm^2 = 400/10,000 = .04 m^2 200,000 * .04 = 2000*4 = 8,000 N of weight about 800 kg mass if g = about 10m/s^2, small car :)

**math**

I said "which it is".

**math**

I suspect they mean every diameter of a circle is a chord, which it is.

**Math**

no 2 * 96 / .75 is not 640

**Ecconomics**

so you want the intersection? 15 - .2 p = -3 + .4 p .6 p = 18 p = 180/6 = 30 q = -3+12 = 9

**Math**

300 (1.00) - 300 (0.05) = 300 (0.95) = 285

**is it falling?**

if so then v = -gt d = -(1/2) g t^2 from second two to second three: d = -(1/2)g (9-4) = -(5/2) g from second three to second four: d = -(1/2)g (16-9) = -(7/2) g ratio = 7/5

**ed tech**

The software on this site does not allow copy and paste.

**ed tech**

You can not do that, sorry.

**Algebra**

diver 1 depth = 12 - 1 t diver 2 depth = 15 - 2 t so 12 - t = 15 - 2 t t = 15-12 t = 3 seconds 12 - t = 12 - 3 = 9 meters

**ART**

The only one I am familiar with is his painting of George Washington. That certainly is a formal soldier. This link is to another type of soldier but at least his head looks red: http://www.google.com/search?q=gilbert+stuart+painting+of+soldier+red+hair&tbm=isch&tbo=u&source=...

**projectile motion**

Nothing to do with the mass. I assume you mean 60 degrees from horizontal in which case the initial vertical velocity component is 5 sin 60 = 4.33 v = 4.33 - 9.81 t at top v = 0 so t = 4.33/9.81 = .441 seconds upward bound h = 4.33 t - 4.9 t^2 for range use 2 t (upward and ...

**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

**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

**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

**English**

Is that chair related to you? Or is that the stairs groaning like your baby coyote?

**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

**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

**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

**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 ...

**Physics**

Trace ray from the top of A and then another from the bottom of A

**Physics**

identical

**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

**math**

1.02 x = 7150 so x = 7150/1.02

**maths**

2*20 =

**pre calc**

top = L^2 bottom = L^2 4 sides = 4*13L total = 2 L^2 + 52 L

**algebra**

Good ! You are welcome.

**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

**easy algebra question, check answer**

yes 3*10^1 * 3*10^5 = 9*10^6 because x^a * x^b = x^(a+b)

**can not help**

Since I do not know what it looks like. You can not copy and paste here.

**Math**

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

**Social Studies**

You are welcome.

**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"

**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 ...

**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

**Physics**

25 * 200 = v * 900 v = 5.55 so yes, A

**do not see pictures**

If you tried to post diagrams, that does not work here.

**Science**

1 = 10 log P/Po where log is base 10 0.1 = log P/Po 10^.1 = P/Po P/Po = 1.259

**Math**

You are welcome.

**Math**

steps >/= 10,000 - 5,274

**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

**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

**maths fractions**

1/4 = 3/12 1/3 = 4/12 x/12 - 3/12 = 4/12 x/12 = 7/12

**20/15 in lowest terms.Express your answer mixed n**

sorry 1 1/3

**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

**Math**

6 out of 20 do not like it. 6/20 = 30/100 or 30%

**mathematical literacy**

2 of cement 2 of lime 2*5 = 10 of sand 2 of water

**history please help! Check my answers!**

Flowers are major, and are only in the third choice, so yes, right.

**math**

ah 40,000 (1.07)^2

**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 ...

**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

**physics**

t cos 52 = (24/2)9.81 = 12*9.81

**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 ...

**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

**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)

**Geometry**

Diameter = 4' radius = 2' = 24 inches Area = pi r^2 = 576 pi in^2

**Math**

r+4 = 2(a+4) or r - 2a = 4 You need to know something more.

**maths**

(5/8)(152) = 5*19 = 95

**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

**Math**

Do + Da = 41 Do + 5 = 2(Da+5) 41 - Da + 5 = 2 Da + 10 etc

**Math**

LOL, subtract 3 from the answers to the question above.

**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 ...

**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

**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

**physics**

32 s more,

**Math 8th grade**

well six one hours plus 2 half hours = 7 hours

**Algebra**

.5 D + 1 B </= 6

**Math**

T = L + 19 T + 4 = 2 (L+4) =================== L+19 + 4 = 2 L + 8 L = 15 T = 34

**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.

**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 ...

**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

**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...

**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) ...

**Math**

-3 / (1/2) = -3(2/1) = -6/1 = -6

**Maths**

common multiple 5 2*2*2 2*2*3 need 5 2 2 2 3 120

**Math**

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

**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 ....

**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

**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

**Math Independent & Dependent.**

the cost depends on how many c = 7 s http://nces.ed.gov/nceskids/help/user_guide/graph/variables.asp

**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)

**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