Wednesday

April 23, 2014

April 23, 2014

Total # Posts: 16,211

**proportional relationship**

proportional means y = m x linear means y = m x + b because of the 4000 feet, this is of form y = -200 x + 4000 which is linear but not proportional

**Math**

doing it your way 72 - (2*12*(1/2)) is 72 - 12 = 60 ft^3 again

**Math**

sand height is 2.5 feet (3' - half foot) 12 * 2 * 2.5 = 12 * 5 = 60 ft^3

**Math Multiplying Fractions**

50*25 * 3 = 3750 m^3 3750 m^3 (1000 liters/m^3) = 3,750,000 liters

**physics**

mass does not matter m v^2/R = m g so v^2/R = g v^2 = 9.81* 41.5 v = 20.2 m/s

**Science**

You are welcome

**Science**

flower, tree and firewood are all biotic. Others are not. Your other answers look reasonable.

**math**

6*2 = 12

**Math**

3*5*3 = 45 3*5*5 = 75 that is 30 more cubic feet

**math**

W * (6/5) = 11/12 (5/6)(W) (6/5) = (11/12)(5/6) W = 55/72

**History!**

10. Daniel Webster !

**History!**

8. European oppression upon the newly independent nations of the Western Hemisphere will be treated as oppression upon the United States itself. <<<<<<<<<

**History!**

4. What made the United States a transcontinental power in 1819? (1 point) Adams-Onís Treaty <<<<<<<<<<<<<<<<<<<<<< Louisiana Purchase Monroe Doctrine*** War of 1812

**Physics NO on 3 !!!**

In the kinetic theory of gases, pressure is due to the strength of the molecular bonds within each gas molecule. I think this is true, but again, not sure. --------------------------- False false false Think of gas banging walls of the container. It depends on how many and how...

**Physics**

If you mix a gas, eventually all the molecules have the same kinetic energy on the average, independent of their mass or the temperature at which they were introduced. I think this is false, but I'm not completely sure. ************************************* I think it true...

**Physics**

(1/2) m (v^2)av = (3/2) kT so m v^2 is the same for O2 and O3 m1 v1^2 = m2 v2^2 m2 = 2 and m1 = 3 3 v1^2 = 2 v2^2 so v2^2/v1^2 = 3/2 v2/v1 = (3/2)^(1/2) TRUE

**Physics**

(1/2) m v^2 = m g h so v = sqrt (2 g h) if I call g = 9.81 v = 19.8 m/s

**science (check new answer)**

Yes, it is A !

**Mrs.Sue?**

American Gothic is the farming couple standing in front of the farm with pitchfork parody

**math**

I am not sure. Google "Venn diagram" or "Venn diagram rules" maybe.

**Physics Please check my answers**

I put in 0.5 meter length, open both ends at 20 deg --> 344 Hz at 40 deg --->356 Hz so yes, true :) I agreed with others.

**Physics Please check my answers**

8. When the temperature goes up, the fundamental frequency of an organ pipe will also go up. Play with this: http://hyperphysics.phy-astr.gsu.edu/hbase/waves/opecol.html

**math**

5 * 4 * 3 * 2

**college chemistry**

I do not think the 1/2 cup has anything to do with this problem. It just happens that your amounts, the 16 g, 17 g, and 5 g fit in the half cup. I will just have to believe you about kilocal per gram for each type of poison.

**physics**

This can happen if the only forces acting are internal to the system. Think, spinning figure skater pulls arms in and spins faster ang momentum L = I omega for simple dumbell = m r^2 omega decrease r ----> increase omega for same L

**maths**

7 ,7+r, *, *, *, *, *, *, *, 14+2r, Term n = 7 +r(n-1) term 10 = 7 +9 r = 14 + 2 r so 7 r = 7 r = 1 and we have 7 ,8, 9, 10, 11, 12, 13, 14, 15, 16, n = 19 term 19 = 7 + 1(18) =25

**Student needs UK teacher**

Sorry, I have no idea.

**REVISION**

Unfortunately I have no idea what you are talking about, no experience with UK education. Have sailed Fastnet race though :)

**Science help.**

I answer the ones I happen to see first.

**Science help.**

You are welcome.

**Science help.**

Yes white fur Yes wind water animal feces Would fruit flies be an invasive species in Canada? I think they live inside and certainly not in Canadian winter outside. I would bet on the burlap bags. Alligator is certainly exotic in Minnesota, not native, however I do not think i...

**science**

Now really read !!! " Friction turns kinetic energy into heat. "

**science**

friction between tires and the road and air drag and friction in the wheel bearings stopped her. Friction turns kinetic energy into heat.

**Physics**

isochoric is constant volume.

**physics**

temp and pressure and so forth have NOTHING to do with what happens to the density here. You STILL have 4 g in the container before you had 4 g/100 cm^3 or .04 g /cc now you have 4 g/50 cm^3 or .08 g/cc

**physics**

P V = n R T R = .082 liter atm/(mol deg K) P = 2.5 V = 1 T = 273+30 = 303 so 2.5 (1) = n *.082 * 300 n = .10162 moles .10162 * 6.022*10^23 =.612 * 10^23 = 6.12 * 10^22 about 6*10^22

**Precalculus II**

Cool problem by the way, congratulate teacher !

**Precalculus II**

2 a = 15.3 - 8.7 so a = 3.3 d = (15.3 + 8.7)/2 = 12 logically enough T = full period = 365 so sin 2 pi t/T = sin .01721 t so b = .01721 sin (.01721 t - c) = 0 when t = 80 .01721 (80) - c = 0 c = 1.377 so in the end D = 3.3 sin (.01721 t - 1.377) + 12 put in t = day of the year...

**definitions**

partners ?

**Ed. Tech.(Need answers checked)**

1. a. Irresponsible behavior 2. a. Using a password-protected website and making sure only specific friends can see it.

**algebra**

Now I showed you how to do compounding. Do it.

**algebra**

19,900 *1.03^10 = 26,744

**algebra**

2. What is the factored form of x x^2 + 6x + 8? (1 point) (x + 5)(x + 3) (x + 4)(x + 2) <------ 2*4 = 8 (x + 7)(x + 1) (x + 3)(x + 3) 3. What is the factored form of x x^2 – 7x + 12? (1 point) (x – 5)(x – 3) (x – 6)(x – 1) (x – 5)(x – 2) (...

**algebra**

1. Which number makes this equation true? I assume you mean v^2 + 10v + 16 = (v + 8)(v + ?) (1 point) 2 <-------------- 4 6 8

**Physics**

60 sec/ min *60 min/hr = 3600 seconds/hour He assumed 8 hours of daylight but as he said you will not get the full force for 8 hours.

**science**

These are fundamental questions that you should be able to answer easily with your text but I see no attempt here by you to do so. Please tell us what your answers are and post only the ones that you are having trouble with.

**Physics**

These are fundamental questions that you should be able to answer easily with your text but I see no attempt here by you to do so. Please tell us what your answers are and post only the ones that you are having trouble with.

**physics**

v^2/R or omega^2 R omega = 2 pi (1 revolution/(24*3600 seconds) so omega^2 = 5.29*10^-9 R = 6.38*10^6 meters so omega^2 R = .0337 m/s^2 (not much, about g/300)

**Algebra 1 (Reiny)**

y^10 / y^1 = y^10 y^-1 = y^9

**science**

saturated salt solution with some solid salt left in the bottom. Solubility is 38.47 grams NaCl for 100 grams water. see: http://en.wikipedia.org/wiki/Solubility_table

**Physical**

change of momentum = .14 * 38 average speed during stop = 38/2 = 19 time to stop = t =.15/19 = .00789 seconds F = change in momentum/time = .14*38/.00789 = 674 Newtons (ouch)

**math**

2.5 + 2 * 5 * tan 4 = 2.5 + 10(.07) = 3.2 inches

**Physics**

You are welcome :)

**Physics**

a = change in velocity /change in time = 3.5/t what is t? average speed is (3.5 + 0)/2 = 1.75 (that is part c) 1.75 t = 1.5 meters t = .857 second (that is part b) so a = 3.5 / .857 = 4.08 m/s^2 ( part a) when acceleration is constant, average speed during acceleration is (ini...

**Math**

speed at outer radius is the same w1 * r1 = w 2 * r 2 where w is radians/second so 2000 * 20/16

**math**

Or just figure out it is one quart per gallon in the first place :)

**math**

64 punch 64*5 punch ------- = ---------- 16 grape x oz grape x = 5*16 = 80 oz grape 80 oz * 1 quart/32 oz = 2.5 quarts

**Physics**

You are welcome.

**Physics**

.75 = (1/2)9.8*t^2 t^2 = .153 t = .391 second

**Algebra 1 (Reiny)**

4 * 3^4* 2^8/ (2^9 * 3^5 ) I think you mean it that way 4 /(2*3) 2/3

**Math**

(5/6) lb/bag * 12 bags = 10 pounds which is 5 of the 2 pound bags

**math**

x pounds of peanuts + 6 pounds cash = (x+6) pounds mix 2 x + 4 * 6 = 2.5 (x+6) 2 x + 24 = 2.5 x + 15 .5 x = 9 x = 18

**Physics**

http://www.jiskha.com/display.cgi?id=1391481178

**physics**

Fspring = -kx where x is extension up = -12 x N m = 0.35 kg Weight = .35 * 9.8 = 3.45 N How far will it drop before the force up = the force down? (the equilibrium position) -k (-x) + m g = 0 12 x = -3.45 x = -.2875 How much potential energy did it lose going from x = 0 to x =...

**Physics**

as with any parabola, it crosses the finish height twice, once on the way up and again later on the way down. We want it later coming back down so use the + sqrt and not the - sqrt for t

**Physics**

I solved the quadratic equation if a x^2 + b x + c = 0 then x = [-b +/- sqrt (b^2-4ac) ]/2a You had this in algebra I suspect. It works fine for 0 = (Hi-h) + Vi t - (1/2) g t^2

**Physics**

here is the method: http://www.jiskha.com/display.cgi?id=1391459618

**Physics**

I did this today as well. Click on links at the bottom of this page.

**Physics**

I just did this as well look at the bottom of this page and click on what looks familiar

**Physics**

scroll down

**math**

If you just want an estimate then about 60*10^-5 = 6 * 10^-4

**Physics**

p1 = 180 atm V1 = 45 m^3 p2 = 60 attm V2 = ? adiabatic p1 V1^gamma = p2 V2^gamma gamma = Cp/Cv for ideal monatomic about 1.67 180/60 = (V2/45)^1.67 ln 3 = 1.67 ln(V2/45) ln (V2/45) = .658 V2/45 = e^.658 = 1.93 V2 = 86.9 m^3

**Physics**

Thot = 266 + 273 = 539 Tcold = 115 + 273 = 388 That is all you need for Carnot efficiency eff = 100 (1 - Tc/Th) = 100(1-388/539) =28 percent

**Physics**

You are welcome :)

**Physics**

Yes, total momentum before = 0 total momentum after = 0 so m v + M V = 0 of course the little one has higher VEOLICIY but equal and opposite momentum

**Science--Physics--check answers**

7150 = F * 11 so F = 650 Newtons exerted by player since the velocity is constant that is exactly equal and opposite to the friction force Just use horizontal force. There is no up or down motion so vertical force does no work.

**Physics**

4 feet =1.2192meters (type **** 4 feet = meters ****into Google search box) h = Hi + Vi t -4.9 t^2 0 = 1.22 + 5.3 t - 4.9 t^2 or 4.9 t^2 - 5.3 t -1.22 = 0 solve quadratic t = [ 5.3 +/- sqrt (28.1+23.9) ]/9.8 use far answer t = 1.28 seconds 1.28 * 2.37 = 3.03 meters

**Global Studies (Please help)**

The others all fought like mad!!!!!

**Global Studies (Please help)**

Colorado Became a State August 1, 1876 That is 11 years after the Civil War ended.

**Physics**

10.4 t = (1/2)(2.97) t^2 t = 7 seconds 10.4 t = 72.8 meters

**Physics**

it did 126 -77 = 49 kcal work 100 * 49/126 = 38.9 %

**Zero and Negative Exponents- Algebra**

You are welcome

**Zero and Negative Exponents- Algebra**

3 a^4 c^3 / b^2 -1/(-5)^2 = -1/25 -1 z / y^7 -3n = -3(-24) = +72 (-2)^72 = 2^72 because even power = 4.7*10^21 very big number

**Zero and Negative Exponents- Algebra**

ANYTHING AT ALL^0 = 1

**Physics**

Excellent !

**Physics**

You are welcome.

**Physics**

The angular momentum vector resists directional change. <------- YES !!!! You should apply a force with your hand at the edge of the wheel.<------ YES!

**Physics**

a) 300 N•m YES (or JOULES) b) 2100 N•m YES (or Joules c) net force=200N and net work=2400N•m. *************** I get + for pull and - for friction so net = 175 - 25 = 150N Net work = 150 * 12 = 1800 Joules and 1800 = 2100 -300 indeed ********************* I'm...

**Physics**

2. A car slows from 108km/h to 90km/h over a course of 4.0s. THe force of the brakes was 1000N. What is the work done by the brakes on the car? My answer: 110 000N +++++++++++++++++++++++++++++++++++++++ How far? In constant acceleration, average velocity is (final +initial)/2...

**Physics**

1. A 50kg person is taking a ride on an elevator travelling up at a steady speed of 2.5m/s. Find the time fo the elevator trip if the elevator does 4900 J of work on the person. My answer: First I used the formula f=mg to find the force and got -490N. ************ - 490 N is g...

**Physics**

Good, you are welcome :)

**Physics**

north momentum = 10 m east momentum = 15 m final mass = 2 m final north v = 10 m/2 m = 5 m/s final east v = 15 m/2 m = 7.5 m/s |v| = sqrt(25+56.25) = 9.1 so yes

**Physics**

Once again, it is true again and again: Momentum before = momentum after if no EXTERNAL force on system, like here: 0 = 5 v + 3 * 3 v = -9/5 = -1.8

**Physics**

I guess both the cup and the water started at 30 C and ended at 35 C so they went up 5 C heat in = .6*.22*5+2.4*1*5 = 12.66 KCal heat out = 2.34 * c * (210-30) = 421 c KCal heat in = heat out 12.66 = 421 c c = 0.03 are you sure you added 2.34 kg of this stuff and not maybe 2.3...

**Physics Please check my answers**

3. I would say yes assuming g constant, p = rho g h Of course it also depends on velocity and acceleration 4. That is ARCHIMEDES !!!!!!! 5. Pascal did lots of things, but not Archimede's Principle 6, No, no, no !! look up "Bernoulli's principle. 7. is TRUE !!!! Be...

**Physics**

You are welcome.

**Physics**

momentum before = momentum after 1300 * 2 + 400 * 0 = 1700 v v = 1300 * 2 / 1700 v = 1.5 m/s

**History8**

I would also pick B but many of those works were after the Compromise of 1820 which kind of spoiled some of the good feelings.

**math --- pls check my work!**

Good :)

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