# Posts by Damon

Total # Posts: 29,823

**Physics 20**

A is 7620 m/s B is 2.71*10^20 kg and for heaven's sake use SCI units, do not use km and hours or something. Use meters, seconds, Newtons, kilograms. 1 hour = 3600 seconds 1 km = 1000 meters

**Physics 20**

B) v(9.06*10^3) = 2 pi (311) v = .216 m/s I do not think so, suspect you mean 311km not 311 m that would give v = 216 m/s then 7620^2 = G Ma/r 7620^2 = 6.67*10^-11 Ma/311 Ma = 2.71*10^20 kg

**Physics 20**

v^2 = G Me/r v^2 = (6.67*10^-11)(5.97*10^24) /6.85*10^6 v^2 = 5.81 * 10^7 = 58.1*10^6 so v = 7.62*10^3 so v = 7620 meters/second

**Physics 20**

A)when in orbit about earth mv^2/r = m (G Mearth)/r^2 solve for v B) same equation but get v immediately v T = 2 pi r then m v^2/r = m Ma(G/r^2) m , mass of sat cancels we know v solve for Ma

**Physics 20**

I did B

**Physics 20**

Weight is NOT in kg but in Newtons !!!!!! F = m * 9.81 = 154*9.81 = 1510 Newtons

**Physics 20**

A) F = G m Me /r^2 at surface G Me/r^2 = 9.81 B) answer to A*r^2/(r+222,000)^2 but if you try to measure it with a scale, zero because F is balanced exactly by mv^2/R if in orbit which is the answer to part C. Really weight in orbit means nothing.

**Physic**

x = 1.6 (pi)cos(pi*1.3 +pi/3) = 5.03 cos (1.63 pi) = 5.03 * .397

**Algebra**

(A/2) -5 = 35 A/2 = 40 A = 80

**Health**

yes. Despite the act that it ends in s, it is one disease.

**Physics 20 Energy**

m g (change in height) 85 * 9.81 * 2.4 *1000 Joules

**Physics 20**

5(2.5)^2 =5*6.25

**huh??**

It is a four dimensional pool?

**Chemistry**

H2O = 18 g/mol so I have 5.5/18 mols water you get two mols H2O for every mol of O2 so I used 5.5/36 mols O2 O2 = 32 g/mol so 5.5*32/36 = 4.89 grams O2

**Chemistry**

Fe2O3 + Al ---> Al2O3 + Fe same number of mols of Fe as of Al Al = 30 g/mol so 225/30 mols of Al so 225/30 mols of Fe so (225/30) mol mass of Fe (225/30)56 = 420 grams of iron

**Nope**

Look at it on a number line. for positive x-3 x must be to the right of 3 but then sqrt x must be greater than sqrt (x-3) which is not possible. If it were -3 on the right, that would be different (x-3)^.5 - x^.5 = 3 square both sides [(x-3)^.5-x^.5][(x-3)^.5-x^.5] = 9 (x-3)-2...

**Physics 20 Gravity**

11.2 m/s^2 as compared to 9.81 on earth

**Physics 20 Gravity**

g = F/m = G M/r^2 where G = 6.67*10^-11 M = 7.66*10^24 r = 6.74*10^6

**English**

maybe something like: Increased government subsidies would make US manufacturers more competitive with heavily subsidized foreign industries.

**Algebra**

height/shadow = 3.4/1.73 = h/48.25 so h = (3.4/1.73)48.25 which is 3.4 * 48.25/1.73 or 94.8 Draw a picture !!!!

**maths help plz sir damon steve or reiny**

This might help: http://tutorial.math.lamar.edu/Classes/DE/HOVariationOfParam.aspx

**whoops**

825/10,000 or 33/400

**Algebra**

8.25/100 = 825/1000 divide top and bottom by 25 to get = 33/40

**Algebra**

.06*$70 = $4.20 it is supposed to be in dollars accurate to the penny

**Algebra**

120-84 = 36 (36/120)100 = 30%

**Math**

[ (7/3) +2 ] /[-3 -(3/2)] (13/3) / (-9/2) = -26/27 I get B

**chemistry**

I suppose w is weight? I suspect you mean mass in grams water is about 1 gram/cm^3 or 1 kilogram/liter so our NaCl here is .075*1 = .075 kg per liter or 75 grams/liter so the real question is How many mols is 75 grams of NaCl NaCl = 58.5 grams/mol (23+35.5) so 75 g (1mol/58.5g...

**algebra**

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

**algebra**

0.164*188 = 30.8

**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.

**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 ...

**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...

**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

**Oh, use Reiny reply**

I did not see the reversal of direction

**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.

**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"...

**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

**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 ...

**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

**math**

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

**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...

**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.

**oic**

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

**Algebra**

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

**Algebra**

LOL - three ways to get at that same parabola

**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

**math please help**

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

**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

**Maths lit**

32*0.794 Kg

**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

**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.

**MATH**

11 - G

**math**

(5/20)100 = 25%

**sorry, yes**

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

**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

**Partial Sums and finding a certain term**

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

**Algebra**

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

**Triangles math**

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

**math**

2/5 of 5/12 = 1/6

**math**

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

**social studies**

and you are right.

**physics**

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

**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 = ...

**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

**LOL - hardly**

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

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

5/16 = .3125 which is 31.25 %

**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.

**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

**physics**

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

**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)

**Maths**

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

**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

**Algebra 2**

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

**Algebra 2**

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

**Maths**

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

**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

**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.

**math**

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

**Algebra 6**

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

**Algebra 2**

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

**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

**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

**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

**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 ...

**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

**Math**

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

**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

**math**

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

**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

**maths**

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

**science**

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

**Physics**

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

**maths**

42(3/7) = 18

**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

**Math**

150 * .05 pounds

**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

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

The word "electrolysis" gives it away John1.

**water--> Hydrogen and Oxygen**

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

**Intro to stats**

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

**calculation error**

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