# Posts by Damon

Total # Posts: 30,065

**Maths: Surds**

a(a+b) = 100 but b = 2a/(1+sqrt5) a [ a + 2a/(1+sqrt5) ]=100 a^2 [ 1 +2/(1+sqrt5) ] = 100 etc

**Maths: Surds**

I do not see your picture but suspect you are talking about what is often called the "golden ratio". http://en.wikipedia.org/wiki/Golden_ratio

**Chemistry**

if you have 2 moles of B you need 6 moles of A In other words you do not have enough A I guess I just said 2) :)

**algebra**

conversion factor is (14 gal/340 mi) (14 gal/340 mi)(544 mi) = 22.4 needed for whole trip so 22.4-14 = 8.4 more needed ============================= with proportions (I do physics not math so not my thing) 14/340 = x/544 so x = (14/340)544 again

**Physics**

a = change in velocity/time = 105/1.2*10^-3 = (105/1.2)10^3 x = 40(1.2)10^-3 - (1/2)at^2 = 40*1.2*10^-3 -(105/2.4)10^3 (1.2)^2 10^-6

**physics**

u = 42 cos 36 horizontal speed so t = 27/(42 cos 36) Vi = 42 sin 36 initial speed up h = Vi t - 4.9 t^2

**Physics**

0.5 m^3 * 2.70 * 10^3 kg/m^3 = 1.35 *10^3 kg = 1350 kg

**Calculus**

I do not see how it could be otherwise. If there were a singularity at infinity resulting in an undefined limit, then how could the domain include plus and minus infinity?

**math**

2.2222 + 4.375 = 6.6 so p = 13.2

**math**

4 3/8 * w = 9 13/18 35/8 * w = 175/18 9/9 (35/8) * w = 4/4 (175/18) 315 w = 700 w = 140/63 = 2.222...

**Technology HURRY**

It is not B

**stats**

keep this link handy: http://davidmlane.com/hyperstat/z_table.html

**Algebra 2 help its urgent please(:**

tan 62 = h/112 so h = 112 tan 62

**physics**

u = 24 m/s forever x = u t where t is time to fall 124 m h = (1/2)g t^2 124 = 4.9 t^2 t = 5.03 seconds so x = 24 * 5.03 = 121 meters

**Chemistry**

22.4 liters /mol at STP so the real question is how many mols of H2 produced wise to balance equation: Mg + 2HCl ----> MgCl2 + H2 so One mol of H2 for every mol of Mg Mg = 24.3 g/mol 4.8 g/24.3g/mol = .198 mol of Mg so .198 mol H2 .198 mol (22.4 liters/mol ) =4.42 liters H2

**proportion and percentages problems**

conversion factor is (£396.00/12 w) a) 1 w(£396.00/12 w) = £33 b) 9 w(£396.00/12 w) = £198 c) 25 w (£396.00/12 w) = £825

**Language**

You are welcome.

**Language**

where do you see petals? On a fl---- ?

**proportion and percentages problems**

You are welcome.

**proportion and percentages problems**

4 dozen = 4*12 = 48 letters so 1.200 kg/48 letters is our conversion factor, same top and bottom a) 1 let (1.2 kg/48 let) = .025 kg or 25 grams b) then 10 let = .25 kg = 250 grams c) 38 let(1.2kg/48 let) = .95 kg = 950 grams

**Language**

oh, of course :)

**Language**

what is the opposite to host? Maybe enemy? Evil landlord? I am not going to type the politician's name ?

**MATH**

distance = speed * time here 38 mi = 2mi/h * t t = 38/2 hours or 19 hours

**math help plz really urgent**

8 = log I1/s 6 = log I2/s 8-6 = log I1/s - log I2/s so 8 -6 = log (I1/I2) = 2 10^log(I1/I2) = I1/I2 = 10^2 = 100 so I1/I2 = 100

**Algebra**

14 x^2 -12 x^2 = 2 x^2 3 x + 11 x = 14 x 4 - 3 = 1 so 2 x^2 + 14 x + 1 ============================ 4 x^2 - 2 x^2 = 2 x^2 -5 x + 1 x = - 4 x +4 + 8 = 12 so what do you think ?

**social studies**

You have no 3 proofread what you typed please.

**social studies**

1. is indeed C The rest makes little sense; proofread.

**physical science**

C is your hard drive Hi. We can not get there from here.

**Physics**

call unknown vector U U = 0 i + |C| j = [bx+cx] i + [by+cy]j |C| = sqrt(7.1^2+3.1^2) so bx + cx = ux = 0 bx = -cx = -7.1 and by + 3.1 = uy = |C| so by = |C| - 3.1 B = bx i + by Jj

**Us history**

Well first of all what do you mean by "Annual rights"? A right is a right, it does not expire after a year even if there is an election. Now if you are looking for rights, the best place to start is not the Declaration but the first ten amendments to the Constitution...

**Chemistry**

you want 2 mols (half a liter of 4N) H3PO4 = 3+31+4(16) grams/mol

**Chemisty**

.300 * 5 = 1.5 mols HNO3 = 1 + 12 + 3(16) grams/mol

**Science**

fossil record?

**Grade 11 Physics: Forces**

.55 m g = 140 m = 140 /[ .55*9.81 ]

**nobody knows**

meaningless, area of what?

**Math**

9 - 8*7 + 6/3 = 9 - 56 + 2 = -45

**Math**

length = 4 x width = 3 x area = 12 x^2 = 4800 so x^2 = 400 x = 20 3x = 60 4x = 80

**maths**

area = 96 * .75*.75 = =96*9/16 =6*9 = 54 m^2 54/9 = 6

**math**

6(10) + 5(1) = 65

**Algebra**

-4 -2 +2

**algebra**

(-3)^2 -5(-3) + 1 = 9 + 15 + 1

**math**

65

**Math**

when you multiply by 10 in our conventional tens base number system, move the decimal point one place to the right. for example 0.27 * 10 = 2.7

**physics**

goes .5 Vi in the first half second for the rest of the trip the average speed is Vi/2 (because Vi at start, zero at end, and constant a) 5 = .5 Vi + (Vi/2) t = t is the time to deaccelerate from Vi to 0 v = Vi - 6 t so t = Vi/6 so 5 = .5 Vi +(Vi/2)(Vi/6) Vi^2/12 + Vi/2 - 5 = ...

**phy211**

first part final v = a t = 40 m/s average v = 20 m/s x = 0 + 20(20) = 400 m second part v = 40 x = 400 + 40(20) = 1200 m third part Vi = 40 average v = 20 time = 40/3 = 13.3 x = 1200+20(13.3) = 1466 m

**Math, Data Management**

google "permutations" p(12,2) = 12!/(12-2)! = 12!/10! = 12 * 11 = 132

**draw a flowchart wich genrates frist 50 items of t**

Well, not really :) But I have boxes of it in the attic.

**draw a flowchart wich genrates frist 50 items of t**

x(1) = 1 x(2) = 2 do 1 for n = 3 to 50 1 x(n)= x(n-1)+x(n-2) print or store the results the end

**physics**

v = 3 t x = 1.5 t^2

**Algebra**

No idea, please look at my reply to your previous question.

**Algebra**

(4x^5 y^6 z)^2 (5x^9 y^12 z)^3 ???????????????? if so 16x^10*125x^27 * y^12 y^36 * z^5 = 2000 x^37 * y^48 * z^5 note a^b * a^c = a^(b+c) (a^b)^c = a^bc

**Physics**

m g h 100 * 10 * 1.5 =1500 Joules

**math**

** v c s n| x x x f| x x x m| x x x p| x x x v = vanilla c = choc etc n = nuts f = fudge m = marshmallow sure enough, 12 x marks :)

**Maths**

first a boy, take him out to the principal's office, then a girl? m + 12 students boy first m/(m+12) now we have (m-1)+12 students pick a girl 12/(m+11) so the product is 12m/[(m+12)(m+11)] or 12m/(m^2 + 23m + 132)

**Physics**

u = 27 cos 45 forever Vi = 27 sin 45 at start h = Vi t -4.9 t^2 = t (Vi -4.9t) h = 0 at ground so at ground at t = 0 of course and at t = 27 sin 45 /4.9 range = u t max height at t = half that t h = Vi t - 4.9 t^2 second question nonsense, from where

**Physics**

Since this is physics, I assume you use SCI units, meters, seconds, newtons, kilograms ... x direction 31min * 60 s/min = 1860 seconds u = x velocity = 109000meters/3600 seconds =30.3 meters/second x displacement component = 30.3*31*60 = 56,358 meters y direction 83,000/3600...

**Physics**

north 990 sin 45 = y component west 990 cos 45 = NEGATIVE x component south is -990 y component and zero x component

**math**

88*20 = 1760 in^3

**huh? sin(2x) /5x maybe**

well the point is that sin x ---> x -x^2/2 + ....... as x------> 0 sin x ---> x so sin(2x) / 5x ----> [2x - 4x^2 ...]/5x as x---> 0 sin(2x) /5 ---> 2x/5x = 2/5

**mathematics**

ax + ab = c agree so far but ax = c-ab x = (c-ab)/a or x = c/a - b

**Math**

subtract 2 from both sides 2x = 2 multiply both sides by 1/2 x = 1 or just think from the start what plus 2 = 4 well, 2 of course so 2 of them is 2 so one of them is one

**Physics**

None if there is no friction. You could ask how much force to accelerate the cart. But if you do that, do in in kilograms and Newtons and meters and seconds. Pounds are too confusing.

**Physics**

u = 15.5 cos 53.5= 9.22 m/s forever Vi = 15.5 sin 53.5 = 12.5 initial h = Hi + 12.5 t - 4.9 t^2 h = 0 at ground Hi = 4.9 t^2 -12.5 t Hi = 4.9(5.37)^2 - 12.5(5.37) Hi = 82.1 meters v = Vi -9.81 t v = 12.5 - 9.81(5.37) = - 40.2 m/s

**American government**

enforce, not force otherwise ok, but if you google articles of confederation I am sure you will find more.

**Math**

Left side (cos/sin)/(1/sin -1) cos /(1-sin) multiply top and bot by (1+sin) cos(1+sin)(1-sin^2) or (1+sin)/cos right side (1/sin +1) /( cos/sin) (1+sin)/cos same

**Math**

a + s = 90 so a = (90-s) 3 a + 2 s = 250 so 3(90-s) + 2 s = 250 etc

**solar science physics**

ah come on. After overwhelming Hoover dam, it starts getting those nuc plants lined up: "An ideal grid-tied inverter works as a perfect voltage source, and changes the grid voltage and frequency to match its own. "

**Huh**

a = F/m if the force is the same and the mass is the same, then the acceleration is the same.

**Math**

(sin/cos + cos-/sin-)/[sin/cos-cos-/sin-] sin -x = -sin x cos -x = cos x (sin/cos - cos/sin)/[sin/cos+cos/sin] multiply top and bottom by sin cos (sin^2 - cos^2)/(sin^2 +cos^2) but sin^2+cos^2 = 1 sin^2-cos^2 but sin^2=1-cos^2 1 - cos^2 -cos^2 1 - 2 cos^2 well, that is what is...

**Physics**

If the velocity versus time is straight, then its slope, the acceleration, is constant a = change in v/change in t = (29.3 - 0)/29.9 calculate a v = Vi + a t but Vi = 0 so at t = 19.9 v = 0 + a (19.9)

**Maths Probability**

ppo 4/11 * 3/10 * 7/9 = a pop 4/11 * 7/10 * 3/9 = b opp 7/11 * 4/10 * 3/9 = c add a+b+c for the answer to (1) =============================== first is p = 4/11 second is p = 3/10 third is o = 7/9 answer to (2) is 4/11*3/10*7/9 for ( 30), Bayes try http://en.wikipedia.org/wiki/...

**Algebra**

Now let me see in F, 32 to 212 = freeze to boil in C, 100 = freeze to boil so change of 180 F is change of 100 C so change of F = (180/100) change of C = 9/5 now when C = 0, F = 32 so F = 32 + (9/5) C that settled, what is 52 F 52 = 32 +(9/5) C 20 = (9/5) C C = 100/9 = 11.1 ...

**Science**

Nah, the zero part counts total distance/total time

**Algebra**

It is particularly helpful if you have a whole string of them.

**Algebra**

You are welcome.

**doing units science way**

Yes, but people in science have a particular approach, Type the units in such a manner that the ones you do not want cancel we can use 6 meters / 1 minute or we can use 1 minute / 6 meters (both are the same top and bottom, just different units. For this problem one minute IS ...

**Algebra**

60 mi/h (1.6 km/1 mi) = 96 km/h 4 h( 96 km / h) = 384 km

**Maths**

100 p + 30 g + 5 c = 1,000 p+g+c = 100 so c = 100 - p - g 100 p +30 g +5(100-p-g) = 1,000 95 p +25 g = 500 we know p+g < 100 or we have <1 c p and g must be integers, no half goats allowed well 95 times what is a multiple of 25 95 = 5*19 so 95*5 = 19*5*5 =475:) try 5 ...

**Physics**

Where to start? My experience is with the earlier egg drop projects but there are some ideas here: http://www.google.com/search?q=egg+car+crash+project+ideas&ie=utf-8&oe=utf-8 What you can do depends on the ground rules for your particular project, specifically what materials ...

**Math**

1 meter/20,000 meters is 1 meter/20 km square that for area instead of length 1 meter^2/400 km^2 so (3/400) square meter or in centimeters 1 sq meter = 10,000 sq cm so 30,000/400 = 300/4 = 75 cm^2

**Huh?**

Let me get this right: You want me to type an entire linear algebra course into this tiny box on my screen?

**Physics**

weight = m g normal force = m g cos 37 friction force up slope = .15 m g cos 37 proulsion force down slope = m g sin 37 net force = m g (sin 37 - .15cos 37) = m a so a = g(sin 37-.15 cos37) calculate a from that now v = a t = 5 a

**math**

(87+75+93+85+x)=88*5

**Science Please Help**

They all look true to me.

**slight clarification (physics)**

a = -9.8 m/s^2 = g (1/2) a = -4.9 m/s^2 so distance = (1/2)g t^2 +48 t + c distance = -4.9t^2 + 48t + c, where c is the initial height

**Physics**

1. b right 2. AhhhgggHHH a is 1 g downward the whole time whatever is airborne 3. b right 4. sqrt(10^2+10^2) =10sqrt2 = 14 c 5. c! when you reach steep enough it goes to zero 6. B ! the forces are ALWAYS equal and opposite (Law 3) however unless the friction on the ground or ...

**Chemistry**

CH4 = 12+4 = 16 g/mol O2=32 g/mol CO2 = 12+32 = 44 g/mol CH4 + 2O2 ---> CO2 + 2H2O I guess we want just the CO2 gas, although that H2O is initially steam same mols of CO2 as mols of CH4 1000 grams / 16g/mol = 1000/16 mols of CH4 so 1000/16 mols of CO2= 62.5 mols quick ...

**Chemistry**

quick esstimate: CO = 12+16 = 28 g/mol about 22.4 liters/mol at stp so we are talking around 28*20/22.4 = 25 grams of CO +10 grams of rubber = 35 grams total will the air lift that? 1.17*20 = 23.4 grams of buoyancy no way, not close

**Physics**

1 d

**Physics**

4. It is stopped, but the acceleration is STILL -9.81 m/s^2 from the time it is launched until it hits the ground or something.

**Physics**

3. The acceleration of g = -9.81 m/s^2 is CONSTANT, even if the speed is zero !

**Physics**

2. 45 - 10*3 = 15 which is c

**Physics**

1. c is not correct. a particle moving at constant velocity has no acceleration. However how could a particle with constant acceleration stay stopped?

**You try first**

Hey, I already took 8:01, freshman physics. I am here to help if you get stuck, not to do the problems for you. These are very basic questions

**Physics**

acceleration and velocity are vectors. They have magnitude and direction. In your car, speedometer gives speed but you need a speedometer AND a compass for velocity acceleration is the rate of change of velocity. If you go in a circle at constant speed your velocity changes ...

**No idea**

sorry, do not know

**physics**

Hey, do some yourself. I already took the course. (in 1955)

**physics**

friction force = mu m g = m *(centripetal acc) so mu g = Ac = v^2/R car A .222 g = 19.5^2/R so R g = 19.5^2/.222 car B R g = v^2/.670 so v^2 = .670 [ 19.5^2/.222 ]

**physics**

Ac = v^2/R = omega^2 R omega in radians/second Ac = 9.81*2.28*10^3 (good grief!) omega^2 = 9.81*2.28*10^3/.0297 omega = 868 radians /second 868 rad/s (1rev/2pi rad)(60s/min) = 8287 rpm

**physics**

omega = v/R is the same for each Ac = omega^2 R = v^2/R 284 = omega^2 (.0302) SO Ac = [284/.0302](.0803)