Saturday

February 6, 2016
Total # Posts: 25,127

**Social Studies**

Hmmmm ....... Sort of, but it is a tough argument to make. Perhaps because the cotton gin made a vast spread of cotton plantations possible and therefore made slavery a bigger factor in the economy of the United States than it would have been otherwise, it was a contributing ...
*November 16, 2015*

**physics**

.03*600 = ? Newtons
*November 16, 2015*

**Chemistry**

Hmm, well try to write a balanced equation C2 H4 + 3O2 ---> 2CO2 + 2H2O seems ok so for every mol of C2H4 I get 2 mol water C2H4 = 2*12 + 4*1 = 28 grams/mol so 2 grams is 2/28 = 1/14 of a mol so I get 1/7 mol of water water is 16+2 = 18 grams/mol 18/7 = 2.57 grams of water
*November 16, 2015*

**Social Studies**

You "think" that New Mexico has many Hispanics? OR You know perfectly well and it is well documented that New Mexico has many Hispanic residents? If someone "thinks" it, then it is opinion. if it is simply true and documented, then it is a "fact" ...
*November 16, 2015*

**math**

60 + 180 = 140 km journey length time at x = 60/x time at y = 180/y total time = 60/x + 180/y = 10 now interchange total time = 180/x + 60/y = 8 2/3 = 26/3 two equations 60 y + 180 x = 10 x y 180 y + 60 x = 26 x y /3 multiply bottom equation by 3 60 y + 180 x = 10 x y and 540y...
*November 16, 2015*

**Science**

I agree with those I know. I do not know if this one is right or not. My guess would be that you are correct.: Earth's oceans, atmosphere, and continents began to form during the first several hundred years of Precambrian time. A. True* B. False
*November 16, 2015*

**History**

I guess, although a bit trite. The other possible answers are silly though.
*November 16, 2015*

**Physics**

r = .32 meter c = 2 pi r n = 5200 meters / (2 pi r meters)
*November 16, 2015*

**word problem math**

18 / 15 = 6 / x multiply both sides by 15 x (or "cross multiply") 18 x = 15 * 6 x = 15 * 6/18 = 15/3 = 5 feet
*November 16, 2015*

**SS**

Joan of Arc (Thinking of France today)
*November 16, 2015*

**Algebra 2**

h(t) = 500 - 16 t^2 opens down (sheds water) if the ground were not at h=0 the tool would keep falling into negative h. (down a deep hole) The tool is at its maximum height, h = 500 at the beginning when h = 500 and t = 0 It is also below 500 feet in the imaginary time before ...
*November 16, 2015*

**Physica**

h = (1/2) a t^2 500 = 2.5 t^2 t = 14.1 seconds accelerating up Vi = 5 t = 5 * 14.1 = 70.7 m/s at 500 m then coasting up v = Vi - 4.9 t^2 v = 0 at top 4.9 t^2 = 70.7 t = 3.8 seconds coasting up beyond 500 m v average coasting = 70.7/2 = 35.4 m/s average for 3.8 seconds h = 500...
*November 16, 2015*

**algebra**

34 - 8 = 26 34 + 8 = 42 26 </= n </= 42 or |34 - n| </= 8
*November 16, 2015*

**AP physics 1**

Throw it in the direction opposite from the ship. Let momentum be conserved :)
*November 15, 2015*

**Physics**

north = 6 - 4 = 2 and distance 10 west 4-4 = 0 and distance 8 so distance = 18 km displacement = 2 North
*November 15, 2015*

**Physics 1**

The whole deal is drawing the picture. the wheel is 1 meter down slope from the center line of the vehicle g is x meters from the road normal to road surface along that center line so tan 47 = x/1 x = tan 47 = 1.07 meters but do not put passengers on the roof. (I am a ship ...
*November 15, 2015*

**Algebra**

savings <= 1800-1250
*November 15, 2015*

**Physics**

v = Vi + a t v = 0 at stop and Vi = 160,000/3600 = 44.4 m/s so 0 = 44.4 - .4 t t = 111 seconds how far in 111 seconds You can use d = Vi t + (1/2) a t^2 but it is easier just to use the average speed during the stop. Vav = (44.4 + 0)/3 = 22.2 m/s d = 22.2 * 111 = 2467 meters ...
*November 15, 2015*

**Physics**

The weight of the car is m g Newtons 1380 * 9.81 N moreover rea are talking about pressure over the area of pistons here, proportional to SQUARE of radius 1380 * 9.81 * .029^2 / .24^2
*November 14, 2015*

**Calculus 1**

Look, I took this subject back in 1956. I am not going to do half a million Newton's method approximations for you. I do not need the practice, you do. Sketch it, draw tangents. Try, then if you have trouble post.
*November 13, 2015*

**Physics**

centripetal acceleration = v^2/R Lift of wings = F weight = m g = F cos 20 so F = m g/cos 20 centripetal force = F sin 20 = m g sin 20 / cos 20 = m g tan 20 centripetal force = m Ac = m v^2/R so m v^2/R = m g tan 20 so R = v^2/(g tan 20)
*November 13, 2015*

**Physic**

A at 25 B at 40 B is faster than A by 40 - 25 if you look at B from A then A is going at 15
*November 13, 2015*

**Science**

Well, yes, the wavelength of an electron is shorter than that of a visible light photon and therefore you can resolve smaller objects.
*November 13, 2015*

**History**

You are welcome.
*November 13, 2015*

**History**

I agree with them all although Question 11 was a short lived success.
*November 13, 2015*

**physics - Huh?**

I do not know. It depends how long you sustained the 50 N force.
*November 13, 2015*

**physics**

20 N = 9.81 * m m = 2.04 kg volume = 2.04 kg/7800 kg/m^3 = .000261 m^3 mass of fluid displaced = .000261*830 = .217 kg mass metal - mass fluid displaced = 1.82 kg metal mass metal weight = m g = 1.82*9.81 = 17.9 Newtons
*November 13, 2015*

**Math**

present pay rate = 567/45 = 12.6 $/h new salary = 567*1.1 = 623.7 new hours = .9*45 = 40.5 new pay rate = 623.7/40.5 = 15.4 $/h change = 15.4 - 12.6 = 2.8 $/hour
*November 13, 2015*

**Math 141**

p none on first draw = 48/52 now I have 4 aces in 51 cards p none on second draw = 47/51 so 48/52 * 47/51 = .851
*November 13, 2015*

**Math**

A does
*November 13, 2015*

**math**

1.3 means it grows 30% per week 345 (1.3)^4 = 985
*November 13, 2015*

**Chemistry**

You need 3*1.6 = 4.8 mols of stuff it is 8 mols/liter 4.8 mols ( 1 liter/8 mols) = .6 liters of the strong stuff so mix 0.6 liters of the 8 M stuff with 1 liter of water
*November 13, 2015*

**Math**

yes number of boxes * number of cookies/box
*November 12, 2015*

**Math**

Yes, you did not need help after all :)
*November 12, 2015*

**Math**

x = 8 + 2 y right x = -2 y right so 8 + 2 y = - 2 y because both are equal to x so -4 y = 8 y = -2 then x = -2 y = 4 so I get they hit at ( 4, -2)
*November 12, 2015*

**Math**

4.00 * r = .32 r = .08 or 8%
*November 12, 2015*

**chemestry**

Use P V = n R T to find n, the number of mols in a liter (around 1/22.4 moles/liter but the temp is not zero) then y N2 weighs 2*14 = 28 grams/mol so using my 1 mol/22.4 liters You would have 28 grams/22.4 liters = 1.25 grams/liter you probably want grams / cm^3 though. there ...
*November 12, 2015*

**Algebra**

well for example - 2 - 12 x < -14 -12 x < -12 x > 1
*November 12, 2015*

**Math**

I agree with 1 through 8
*November 12, 2015*

**Pre calc**

check - should be close to continuous compounding 1.375 = e^rt ln 1.375 = 5r r = .0637 or 6.37% sure enough
*November 12, 2015*

**Pre calc**

let x = 1+r 1100 = 800 (x)^(5*365) 1.375 = x^1825 log 1.375 = 1825 log x log x = .1383/1825 = 7.57823 *10^-5 x = 1.00017451 r = x-1 = .00017451 per day 365 r = .0637 nominal per year = 6.37 percent
*November 12, 2015*

**Algebra 2**

60 x = 45 x = .75 1.00 - .75 = .25 which is 25% down
*November 12, 2015*

**Maths**

any real number squared is positive so -(x+5)^2 is negative now go left two on the number line and you are even more negative :)
*November 12, 2015*

**Physics 101**

circumference = 2 pi R = pi D = 31.4 meters 45 deg = 360/8 so 31.4/8 meters 45 rad = 45/(2 pi) circles = 7.162 circles 7.162 * 31.4 = 225 meters 45 circles 45 * 31.4 = 1413 meters
*November 12, 2015*

**Vocab**

well, stocks are pieces of paper representing something valuable but a commodity like a barrel of oil is actually goods with value.
*November 12, 2015*

**Vocab**

I am sorry. I do not know what an "actual" manner means. Perhaps we are talking about a poem that describes a specific story which is likely a ballad (I do not know what a ballard is either)
*November 12, 2015*

**Math**

1.29/0.3 = 12.9 /3 = 129/30 the middle one is easy 4.3
*November 12, 2015*

**Physics**

175 sin 20 The way to remember this is to think of the box on a level floor. Then the component parallel to the surface is obviously zero. and sure enough sin 0 = 0 the normal component is the entire weight when the surface is level and sure enough cos 0 = 1
*November 12, 2015*

**physics b**

4 to 6 is 2 degrees 6 to 12 is 6 degrees, three times as much change in T so 3 Q
*November 12, 2015*

**physics b**

one kg water falls 100 meters potential energy loss = m g H = 1 * 9.81 * 100 = 981 Joules so 981 Joules goes to heat that 1 kilogram 981 J = 1 kg * 4.186*10^3 * delta T so delta T = 981 /(4.186*10^3)
*November 12, 2015*

**Math**

C = 11 n yes but you do not buy a fractional DVD so I think d
*November 12, 2015*

**Maths**

take out 1/4 and try no way :( 4x-1 not a factor of 4x^3 -24 x^2 - 4 x + 120 where did you find this problem?
*November 12, 2015*

**Maths**

long division I get x^2 -4 x + 8
*November 12, 2015*

**physics**

http://www.acoustics.salford.ac.uk/feschools/waves/diffract3.php
*November 12, 2015*

**physics**

more http://physics.about.com/od/mathematicsofwaves/a/interference.htm
*November 12, 2015*

**physics**

Yes, I bet this will help: http://physics.about.com/od/mathematicsofwaves/a/huygensprincipl.htm
*November 12, 2015*

**physics**

You watched that double slit video and do not understand what diffraction is? Maybe look up "Huygen's Principle" I will try.
*November 12, 2015*

**physics**

LOL - first do the diffraction video :)
*November 12, 2015*

**physics b**

8950 J = .174 kg (delta T)[452 J/(kg deg C)] so delta T = 8950 /(.174*452)
*November 12, 2015*

**physics**

Yeah, cool, that is a pretty good U tube
*November 12, 2015*

**physics**

ah, here is a U tube for double slit. I bet that helps http://www.youtube.com/watch?v=iZdWQKaykvs
*November 12, 2015*

**physics**

Here is a diffraction grating Note that the angle of the first maximum depends on the wavelength of the light, which allows you to separate wavelengths by their angle. http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/grating.html Probably the easiest one to understand though ...
*November 12, 2015*

**physics**

Oh my, where to start. Any time a wave encounters something of size the same order as the wavelength, diffraction happens. It does not matter if it is an ocean wave at the tip of a breakwater or a light wave hitting a diffraction grating. Maybe google single slit diffraction
*November 12, 2015*

**Math**

subtract is subtract, algebra or not.
*November 12, 2015*

**Geometry**

(Y2-Y1)/(X2-X1) = (-2 -3)/(5 + 2) = -5/7 I think you have a sign typo
*November 12, 2015*

**Maths**

y = 6 - x so y^2 = 36 - 12 x + x^2 so 2 y^2 = 2 x^2 - 24 x + 72 so 3 x^2 - 24 x + 72 = 36 3 x^2 - 24 x + 36 = 0 x^2 - 8 x + 12 = 0 (x-2)(x-6) = 0 x = 2 or x = 6 x = 6 is trivial because then y = 0 if x = 2, y = 4 so (6,0) and (2,4)
*November 12, 2015*

**physics**

if in meters/ second^2 v = Vi - 9.81 t at the top v = 0 so 0 = 29.4 - 9.81 t t = 3 seconds drifting upawrds Now you could do the 4.9 t^2 thing but it is easier just to use the average speed up which is (1/2)29.4 m/s = 14.7 m/s height = 1.8 m + 14.7 m/s * 3 seconds = 1.8 + 44.1...
*November 12, 2015*

**physics**

and what units ? Yikes ! what do you use for g? 9.81 m/s^2 or 32 ft/s^2
*November 12, 2015*

**huh?**

Thrown at what angle to horizontal? In furlongs / month? It has to do with distance = initial position + Vi t + (1/2) a t^2 but that may not be the easy way to do it. conservation of energy is faster if the max height is all you need.
*November 12, 2015*

**precalc**

log5 (25) 5^(log5(25) = 25 but 5^2 = 25 so log5(25) = 2
*November 12, 2015*

**Physics**

Now I have done several of these. You try. a = dv/dt
*November 11, 2015*

**Math**

(4 oz/serving )(1 pound/16 oz) = .25 pounds /serving 238/.25 = 952 servings that is exact but you must have a typo. No salmon is that big, maybe a bluefin tuna :)
*November 11, 2015*

**math**

y - 3 x = 3 4 x -y = 2 ------------------add 1 x + 0 y = 5 or x = 5 4(5) - y = 2 y = 18
*November 11, 2015*

**Math**

1.62 ---- times 10/10 = 16.2/8 0.8 .0162 ------ times 1000/1000 = 16.2/8 etc 0.008
*November 11, 2015*

**Math**

L w = 3/5 but w = 2/5 so L (2/5) = 3/5 L = 3/2 w L/w = (3/2) /(2/5) = 3/2 * 5/2 = 15/4
*November 11, 2015*

**Math**

Use a number line by the way
*November 11, 2015*

**Math**

now you changed it 12 to 13 = 2.7 13 to 14 = 3.6 13 to 15 = 6.8 + 2.7 + 3.6 = 13.1 so 14 to 15 = 13.1 - 3.6 = 9.5 which is 13 to 15 - 13 to 14
*November 11, 2015*

**Math**

12 to 13 = 2.7 13 to 14 = 3.6 13 to 15 = 6.8 + 2.7 + 3.6
*November 11, 2015*

**chemistry or physics**

about 3*10^8 m/s
*November 11, 2015*

**Math/ Proportions solve using unit rates**

( First my way, then your way :)
*November 11, 2015*

**Math/ Proportions solve using unit rates**

the unit rate is 25/5 minutes rest/hour = 5 minutes rest /hour so 8 hours * 5 minutes rest/hour = 40 minutes rest
*November 11, 2015*

**Math/ Proportions solve using unit rates**

8 hours ( 25 minutes rest / 5 hours ) = 40 minutes rest
*November 11, 2015*

**Physics**

a = change in velocity / change in time = (15 - 5 ) /15 = 10/15 m/s^2 = 0.667 m/s^2
*November 11, 2015*

**chemistry**

distance = speed * time and period = 1/f 413 *10^-9 meters ?=?? 3*10*8 m/s / (6.26 * 10^14) 413 * 10^-9 = .479 *10^-6 ???? 413 = 478 ??? not really
*November 11, 2015*

**Math**

(15+16+17+14+19+x)/6 >/= 16 81 + x >/= 96 x >/= 15
*November 11, 2015*

**Physics**

v = Vi + 3 t 40 = 30 + 3 t t = 10/3 seconds d = 35 (10/3)
*November 11, 2015*

**physics**

a = -2 m/s^2 v = Vi - 2 t v = 30 - 2*5 = 20 at the end so average v = 25 m/s 25*5 = 125 meters
*November 11, 2015*

**Math**

5.Which number is a perfect cube? 5**** 100 125 150 ah 125 = 5 * 5 * 5
*November 11, 2015*

**Physics**

figure at http://i.gyazo.com/47dc49d5ec1eebe950472dba5f692e70.png I will only do the right half (symmetry) 5 kg down on the right half 5 kg * 9.81 = 49 Newtons so tension below B: call it TL TL cos 30 = 49 so TL = 56.6 N so component of TL to the left at B TL left = 56.6sin 30...
*November 11, 2015*

**Algebra**

66/101 = .653 so 65.3 %
*November 11, 2015*

**Math**

Look Princess, we went through this when you were trying to simplify fractions. 22 for example is 2 * 11 2 and 11 can not be factored any further. They are "prime" then 44 = 2 * 22 that is NOT Enough (not prime factors) because 22 can be factored as we know so 44 = 2...
*November 11, 2015*

**Algebra**

here are 4 styles each has possible 5 colors 4*5 = 20 there are 5 colors so 1/5
*November 11, 2015*

**Math**

b + 49/8 = 23/4 = 46/8 so b = 46/8 - 49/8 b = -3/8
*November 11, 2015*

**physics**

3881 = 4.9 t^2 t = 28.1 seconds v = g t = 9.81 (28.1) = 276 m/s
*November 11, 2015*

**ALGEBRA**

the minimum of function 2 is 0 at (-1,0) for the first function 1 y = 4 x^2 + 8 x + 1 4 x^2 + 8 x = y - 1 x^2 + 2 x = (1/4) y - 1/4 x^2 + 2 x + 1 = (1/4)y + 3/4 (x+1)^1 = (1/4) (y+3) so vertex at (-1, -3) SO A
*November 11, 2015*

**top ville college**

2 NaHCO3(s) → Na2CO3(s) + CO2(g) + H2O(g) You one mol of CO2 for each 2 mols of soda so we have .25 mol of Co2 a mole of ideal gas at STP is 22.4 liters so 22.4 / 4 Liters
*November 11, 2015*

**math**

maybe try 87,000 and 98,000
*November 11, 2015*

**science**

pressure = 4 N/2 cm^2 = 2 N/cm^2 force = pressure * area = 2 N/cm^2 * 16 cm^2 = 32 N NOW area is cm^2 , not cm cm is distance along a line cm^2 is area of a surface
*November 11, 2015*

**Math**

2750 /(5*3600) = .15277 which is .15 there are 3600 = 60 * 60 seconds in an hour
*November 11, 2015*

**math**

2.5 cm ( 2 m/1 cm) = 5 m That is one long window !
*November 11, 2015*