Tuesday

May 3, 2016
Total # Posts: 26,155

**Chemistry - Gas Laws**

p = pressure in tire = 14.7 + pgage CO2 = 12 + 32 = 44 grams/mol so 16 g = .364 mol of CO2 so n = .364 T = 295 deg K V = 3.15 Liters then p V = n R T get that p and subtract 1 atm to get gage
*March 22, 2016*

**PHYSICS! are these correct?**

3. A 5-kg box is sliding across a desk that has a coefficient of friction of 0.4. If the box is initially moving at 15 m/s, how far will the box slide before coming to rest. You MUST use the WORK/Kinetic Energy Theorem to solve this. ============================= initial ke...
*March 21, 2016*

**PHYSICS! are these correct?**

2. How much work must gravity do on a 2-kg falling object in order to take it from rest to 20 m/s? ============================ change in potential energy = m g h that goes into kinetic energy. so how far does it fall to go from 0 to 20 m/s? v = Vi + a t 20 = 0 + 9.81 t t = 2....
*March 21, 2016*

**UNITS !!!!!!!**

How much kinetic energy does a 700-gram baseball have that is travelling at 20 m/s? What would be the kinetic energy if you doubled the mass? What would be the kinetic energy if you doubled the velocity? V1= 20 m/s K1= ½ m v1^2 = ½ (0.7 kg)(20 m/s)^2 = ½ (...
*March 21, 2016*

**physics**

V = E times distance like work = force * distance 140 = 29 x x = 140/29
*March 21, 2016*

**physics**

LOL zero, cancels
*March 21, 2016*

**physics**

momentum change = m v force = rate of change of momentum = m v/t 55 * 28/.2 = 7700
*March 21, 2016*

**Physics helllppp**

108,000m/hr * 1hr/3600s = 30 m/s friction force= -.9 m g = -.9 * 9.81 m = -8.83 m F = m a -8.83 m = m a a = -8.83 m/s^2 v = Vi + a t 0 = 30 - 8.83 t t = 4 seconds
*March 21, 2016*

**Physics**

108,000m/hr * 1hr/3600s = 30 m/s friction force= -.9 m g = -.9 * 9.81 m = -8.83 m F = m a -8.83 m = m a a = -8.83 m/s^2 v = Vi + a t 0 = 30 - 8.83 t t = 4 seconds
*March 21, 2016*

**geometry**

(pi d/2)
*March 20, 2016*

**Physics**

one kg object 1 Newton pushing north 1 Newton pushing north east north components 1 + 1 cos 45 = 1 + .5 sqrt 2 = 1.707 Newtons north east components 1 sin 45 = .5 sqrt 2 = 0.707 Newtons east F = sqrt (1.707^ + .707^2) tan of angle clockwise from north (compass angle) = .707/1.707
*March 20, 2016*

**Math**

3 = 2*1.5 5 = 3 *1.666666 ..... 1.5 is not 1.6666.. so it is not geometric 3-2 = 1 5-3 = 2 so it is not arithmetic
*March 20, 2016*

**mathematics**

tan angle = 25/25 angle = 45 degrees
*March 20, 2016*

**Maths**

P(4) = C(10,4) .3^4 .7^6 C(10,4) = 10!/[4! 6!] = 10*9*8*7/[4*3*2] = 30*7 = 210 so P(4) = 210 * .3^4*.7^6 = 0.02 for the second part do that for 7 8 9 and 10 students and add results. Do not spend more that a week at it. If you get frustrated you can approximate a binomial ...
*March 20, 2016*

**Other**

Does it wink at you when you tap it with a hammer?
*March 20, 2016*

**asomaning**

To increase the temperature of one kilogram of Al one degree Kelvin or Centigrade, you must insert 900 Joules of heat energy.
*March 20, 2016*

**physics**

- mg = - .5 * 9.81 = - 4.9 Newtons the whole time if you ignore air frictional drag
*March 20, 2016*

**algebra**

Maybe means multiply first one by 7 and second one by 3 ? I doubt if they have gotten to Cramer or Gauss Jordan. 21 x + 35 y = 175 21 x + 18 y = 90 ---------------------subtract 0 x + 17 y = 85 y = 5 then x = 0
*March 20, 2016*

**physics**

n1 sin theta 1 = n2 sin theta 2 1.33 sin theta 1 = 1 sin 90 sin theta = 1/1.33 theta = 48.8 degrees That is actually the minimum angle for which total internal reflection occurs. Any less than that and it gets through
*March 20, 2016*

**gibberish ???**

Two charges on three vertices? anyway do E = k q/r^2 in the direction from each charge to the spot and add the vectors.
*March 20, 2016*

**physics**

a = 5 m/s^2 v = Vi + a t 25 = 10 + 5 t
*March 20, 2016*

**math**

y = k x^n maybe ? if y = x^2 then n = 2 if y = x^3 then n = 3
*March 20, 2016*

**Physics**

If there is no net force, there is no net acceleration and velocity is constant. Force = rate of change of momentum F = m A if m is constant
*March 19, 2016*

**sir damon help on these as well co-ordinate**

It is a square root sign I suspect and it is not showing up in your font. Her answer is the same as mine.
*March 19, 2016*

**sir damon help on these as well co-ordinate**

30 degrees above negative y axis y = 3 sin 30 = 1.5 x = - 3 cos 30 = -3 (sqrt 3)/2 ( -1.5 sqrt 3 , + 1.5 )
*March 19, 2016*

**math series**

1/(3*1) + 1/(4*2) + 1/(5*3) + 1/(6*4) 1/[(n+2)n] or 1/(n^2+2n)
*March 19, 2016*

**no idea**

I do not know what sort of harmonic series that is. None I know of.
*March 19, 2016*

**Math**

neither, I am not trying to fit that with a line. You might try point - slope but it will not fit very well. Your data is too bumpy to fit well with a straight line.
*March 19, 2016*

**Math**

up, down, up, down could try a polynomial (a x^4 + b x^3 etc...) but they are dangerous when you try to continue them out because they go to infinity for big t maybe a sine wave with an up trend? the domain is 2005 to 2015 the range is 2.25 to 3.51 price = a t + b sin( 2 pi t/...
*March 19, 2016*

**English**

bitte
*March 19, 2016*

**English**

Three and slimy describe nouns, snails, so they are adjectives. "nearby" describes a verb, crept, so it is an adverb.
*March 19, 2016*

**11th grade physics**

A - ROTFL - everything is equal and opposite to everything else B - now we have a problem the two on the same side cancel each other but the two on the opposite charge try to push away at 90 degrees to the side distance from each = sqrt (a^2 + .25 a^2) = a sqrt (5/4) component...
*March 19, 2016*

**Grammer**

.... but I agree that it is usually grammar :)
*March 19, 2016*

**Prob**

well lets figure out probability of all ones, then multiply by 6 1/6 * 1/6 * 1/6 = 1/6^3 now probability of three of any old number is 6/6^3 = 1/36 40/36 = $1.11111 but long term the house should come out ahead :) so $1.12
*March 19, 2016*

**baliga**

divide 3*10^8 meters/second by 1.4 It is ALWAYS less than in a vacuum !
*March 19, 2016*

**math**

.75 * 60 = .3 x x = .75 * 60 / .3 = 150
*March 19, 2016*

**huh?**

I do not understand your notation. What is po3-4 ????
*March 19, 2016*

**Prob/Stats**

p eat = .44 p not eat = .56 p that k say yes (binomial) P(17/k) = C(17,k) .44^k .56(17-k) where C(17,k) = 17!/[k!(17-k)!] do that for k = 8 through 17 and add OR approximate binomial expansion with normal distribution mean = n p = .44 * 17 = 7.48 sigma^2 = 17(.44)(.56) = 4.19...
*March 19, 2016*

**math**

.7 * 225 = 157.50 so no no 70% of original is 30% OFF original
*March 19, 2016*

**mathematics**

Huh Mauricio ????
*March 19, 2016*

**mathematics**

sketch it first length QR = 10 NOTE - perpendicular to x axis so altitude along x axis altitude from P to QR is along x axis and of length 9-3 = 6 so area = (1/2)(6)(10) = 30
*March 19, 2016*

**binomial expansion help!!!**

He said: Actually, just consider the definition of T. Take a peek here, and it should be clear, since the arc length is just ∫ ds = ∫ |dr/dt| dt 88888888888888888888888888 In other words the tangent is along the curve so if you integrate the tangent along the curve...
*March 19, 2016*

**binomial expansion help!!!**

You are welcome.
*March 19, 2016*

**binomial expansion help!!!**

(n+1)n(n-1)(n-2)/24 = 6 k is (n+1)n [(n-1)(n-2) ]= 72 * 2 k BUT [(n-1)(n-2)] = 2 k so (n+1) n = 72
*March 19, 2016*

**binomial expansion help!!!**

(1+x)^(n+1) = 1^(n+1) + (n+1)1^n x + (n-1)(n-2)/2 1^(n-1)x^2 + (n+1)n(n-1)/6 1^(n-2) x^3 +(n+1)n(n-1)(n-2)/24 1^(n-3)x^4 huum (n+1)n(n-1)(n-2)/24 = 6 k (1+x)^(n-1) = 1^(n-1) + (n-1)1^(n-2) x + (n-1)(n-2)1^(n-3)/2 * x^2 so (n-1)(n-2)/2 = k (n-1)(n-2) = 2 k so (n+1)n (2k)/24 = 6...
*March 19, 2016*

**Math**

they have 4/5 2/5 and 2/5 3/5 and 1/5 1/5 and 3/5 or many others like if we say 4/5 = 8/10 or even 16/20 1/10 and 7/10 etc :)
*March 19, 2016*

**math**

3/4 cup / 1/4 tbsp = 3 cups / 1 tbsp
*March 19, 2016*

**Phys 2425**

between wires field is down from one of them and up from the other The B from a wire times 2 pi * distance from the wire is proportional to the current through so 1/2pir = 2/ 2pi(2 -r) 2 r = 2 - r 3 r = 2 r = .66666666667 cm :)
*March 18, 2016*

**Pre algebra**

2 w = L/2 or L = 4 w perimeter = 2(L+w) = 2( 5 w) = 10 w = 10 so w = 1 L = 4
*March 18, 2016*

**Physics**

momentum = m v = .025 * 300 stops in .03 meters average speed during stop = 150 m/s time to stop = .03 meters/150 m/s force = change in momentum/time = .025 * 300 / (.03/150) = 37,500 N do B the same way
*March 18, 2016*

**math**

a + b + c = 408 b = c + 7 so c = b-7 b = a + 5 a + (a+5) + (a+5-7) = 408 3 a + 3 = 408 a + 1 = 136 a = 135
*March 17, 2016*

**mAth**

You are welcome.
*March 17, 2016*

**mAth**

[ (x-2.6)/0.3 ] 3 = -48 (x-2.6)/0.3 = -16 x - 2.6 = -4.8 x = -2.2
*March 17, 2016*

**math**

4/5 * 3/4 * 2/3 = what was left in the end = .4 of original is left at the end call original amount 1 then youngest gets .2 that leaves .8 then middle gets .8/4 = .2 as well that leaves .6 oldest gets .6/3 = .2 ROTFL !!!
*March 16, 2016*

**algebra**

short leg = x long leg = x+8 hypotenuse = 2x-8 so { 2(x-4) }^2 = x^2 + (x+8)^2 4 (x^2 - 8 x + 16)= x^2+x^2+16x+64 4x^2 -32 x + 64 = 2 x^2 +16 x + 64 2 x^2 -48 x = 0 x = 0 works but x = 24 ******************* check 24 , 32 , 40 or /8 3 , 4, 5 LOL yes, right triangle
*March 16, 2016*

**Geometry**

As the problem is stated, of course they will because as it rises the horizontal distance from the pivot point at the ground decreases. If the wires are exactly above the tip of the bean at 60 deg, then they will be closer to the pivot point at more than 60deg Therefore I ...
*March 16, 2016*

**Math**

12 * 20 * 7 * 8
*March 14, 2016*

**physics 11th class**

m g h / t
*March 14, 2016*

**ratios/algebra**

8/5 = 64/x 40
*March 14, 2016*

**Physics**

heat to melt + heat to raise 10 deg = m * heat of fusion + m *specific heat * (10-0)
*March 14, 2016*

**Math**

t = k L/n 6 = k 4/100 so k = 150 t = 150 (16/160) = 15 weeks
*March 11, 2016*

**Chemistry**

only if you know the molar mass of each and the balanced equation so you can see how many moles and therefore grams of A are needed to react with B. So in general, No
*March 11, 2016*

**Math**

it was evidently launched straight up in which case: h(t) = 73.5 + 9.8 t - (1/2)g t^2 g is about 9.81 m/s^2 so h(t) = 73.5 + 9.8 t - 4.9 t^2 at ground, h(t) = 0 so 0 = 4.9 t^2 - 9.8 t - 73.5 and yes you can take 4.9 out approximately 0 = t^2 - 2 t -15 (t-5)(t+3) = 0 t = 5 seconds
*March 11, 2016*

**Algebra**

F = k m g v^2/R (actually k g = 1 because v^2/R is centripetal acceleration) anyway 400 = k (1600) 50^2/800 so k(1600) = 800 * 400 /2500 F = k (1600) 60^2 /600 F = 800*400 *3600 /{2500*600) = (8/6)(36/25)*400 = (4/3)(36)(16) = 768 pounds
*March 11, 2016*

**huh?**

pi r^2 = 3.14 * 64 ft^2
*March 11, 2016*

**Science**

14 agree 15 I suppose but just the word "vital" would do. Depends on what your text says. These questions stink. 16 yes (and that gives away the earlier question :) 17 Heat? Depends on what your particular text says again. 18 yes, evaporates 19 consumer ? 20 yes, ...
*March 11, 2016*

**Science**

8 no idea, check your text for screwy comparison 9 yes d eats plants and fish 10 c yes I suspect 11 I bet on a 12 b I think but minor effect 13 a yes
*March 11, 2016*

**Science**

7 d I think, no light
*March 11, 2016*

**Science**

1 yes 2 no idea what they are getting at. Merry go round correct for physics, not biology 3 c yes 4 yes, came on Mayflower :) 5 c yes 6 c yes
*March 11, 2016*

**maths**

r = 44/2pi = 7 cm area = pi (49) = 154 cm^2 square side = 11 area = 121 cm^2
*March 11, 2016*

**math and science**

v = Vi + a t 0 = 36 + a t t = -36/a d = Vi t + .5 a t^2 40 = 36 (-36/a) + .5 (a)(36^2/a^2) 40 = - 36^2/a + .5 *36^2/a 80 a = -36^2 a = -16.2 m/s^2 then F = m a = -1500(16.2) Newtons
*March 11, 2016*

**Math**

2 x + y = 320 x y = 12,600 so y = 12,600/x 2 x + 12,600/x = 320 x^2 + 6,300 = 160 x x^2 - 160 x + 6,300 = 0 x = [160+/-sqrt(25600-25200)]/2 x = [ 160 +/- 20] /2 x = 90 or 70 try 90 then y = 140 2x + y = 320 Yes, that works try 70 y = 180 2x+ y = 140 + 180 = 320, Yes that works
*March 11, 2016*

**math**

multiply both sides by -1 (-1)(-y) = + y (-1)(3) = -3 so y = -3
*March 11, 2016*

**math**

2 ends are 16*14 2 sides are 4.8*14 top and bottom are 4.8 * 16 so 2(16*14 + 4.8*14 + 4.8*16)
*March 11, 2016*

**math**

13 + 13 = 26 13 hearts and 13 clubs
*March 9, 2016*

**Math**

y = 10 x + 4 (-2, -16) (-1 , -6) (0 , +4} (1 , 14) (2 , 24)
*March 9, 2016*

**Math**

slope = (-6+1)/(1-0) = -5 so y = -5 x + b 9 = 10 + b b = -1 so y = -5 x -1 or 5 x + y = -1
*March 9, 2016*

**PHYSICS ( PERIODIC MOTION)**

if damping proportional to v F = -kx -bv then x = A e^-(bt/2m) sin w' t five cycles is about 3.67 seconds so 1/2 = e^-(3.67 b /.226) take ln both sides -.693 = - -16.2 b so b = .0427 then w' = sqrt (k/m -b^2/4m^2) = sqrt (73. - .035) =8.542 = 2 pi/T T = .7355 s change ...
*March 9, 2016*

**PHYSICS ( PERIODIC MOTION)**

mass = .1136 kg g = 9.81 m/s^2 so weight = .1136*9.81 = 1.114 Newtons spring constant k = 1.114 N/ .134 meters = 8.32 N/m T = 2 pi sqrt(m/k) = 2 pi sqrt (.1136/8.32) = 0.734 s = 7.34 * 10^-1 s
*March 9, 2016*

**Maths**

(1/2)M + (1/3)M + 40 = M multiply by 6 3 M + 2 M + 240 = 6 M 240 = M spent M-40 = 200
*March 9, 2016*

**Science**

In English units, the acceleration of gravity near the surface of earth is about 32 feet/second^2 = g When we used those units, we defined mass in slugs. mass in slugs m = weight in pounds/g = weight in pounds/32 Then we could use Newton's second law F = m a where force is...
*March 9, 2016*

**Math**

one is 16 * 5 the other is (40 - 5) = 35 *5 so 80 *5 [ 16+35 ] = 80*5*51-
*March 9, 2016*

**Physics**

In English units, the acceleration of gravity near the surface of earth is about 32 feet/second^2 = g When we used those units, we defined mass in slugs. mass in slugs m = weight in pounds/g = weight in pounds/32 Then we could use Newton's second law F = m a where force is...
*March 9, 2016*

**english**

verbs like worked SLOWLY or ate quickly An ly at the end is a dead giveaway but is not always the case.
*March 9, 2016*

**Precalculus quadratic stuff**

Lets complete the square to look at the parabola y = -2x^2+16x+40 x^2 - 8 x -20 = -y/2 x^2 - 8 x = -y/2 + 20 x^2 - 8 x + 16 = -y/2 +36 (x-4)^2 = -(1/2)(y-72) so max area occurs when x = 4 and area = 72 zeros are when x^2-8x-20 = 0 (x-10)(x+2) = 0 or when x = 10 and when x = -2...
*March 9, 2016*

**Math**

25 x >/= 5000 x >/= 200
*March 8, 2016*

**Physics HW Plz help**

the fundamental frequency is called the first harmonic Higher harmonics are integer multiples of the fundamental we know 24/3 = 8 1 f = 8 2 f = 16 3 f = 24 4 f = 32 5 f = 40 6 f = 48
*March 8, 2016*

**Algebra**

LOL, yes, just use a square
*March 8, 2016*

**Physics grade 12**

2/x^2 = 8/(12-x)^2 1/x^2 = 4 /(12-x)^2 4 x^2 = 144 - 24 x + x^2 3 x^2 + 24 x - 144 = 0 x^2 + 8 x - 48 = 0 (x+12)(x-4) = 0 x = 4 cm then 12 - x = 8 cm check 2/16 = 8/64 ??? yes right
*March 8, 2016*

**math**

.06 * 300 = 18 empty (answer) .06 * 310 = 18.6 do not show of the 310 310 - 18.6 = 291.4 show up (answer) additionally 300 seats - 291.4 passengers = 8.6 empty seats which is really 18 empty because 40% of a passenger takes a whole seat
*March 8, 2016*

**math**

.98 * 15,000 = 14,700 Only 2 percent will arrive late so your flight will probably be on time. Of course the key word is "probably" and there is no way you can tell if yours is one of the two out of one hundred that are late.
*March 8, 2016*

**No diagram**

If you tried to copy and paste a picture, that does not work.
*March 8, 2016*

**math**

0.06 * 500 = 36
*March 8, 2016*

**history**

http://en.wikipedia.org/wiki/Afro-Asian
*March 8, 2016*

**math**

20 * 8 = 160 player days 0.80 * 160 = 128 player days or an average of 16 players/day
*March 8, 2016*

**phy 231**

x = 1.5 sin (2 pi * .181 t) = 1.5 sin (1.137 t) v = dx/dt = 1.5* 1.137 cos (1.137 t) v max = 1.5 * 1.137 a = d^2x/dt^2 = -1.5*1.137^2 sin (1.137 t) a max = 1.5 * 1.137^2
*March 8, 2016*

**physics**

surface tension is force/length I am going to call density rho, not P. P is confusing because usually pressure. F = m a = rho L^3 * L/s^2 = rho L^4/s^2 so F/L = rho L^3/s^2 but g is L/s^2 so F/L = rho L^2 g if our length scale is h then Y = F/L = constant * rho h^2 g By the ...
*March 7, 2016*

**math help fast**

http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html
*March 7, 2016*

**math help fast**

http://www.mathsisfun.com/algebra/sequences-sums-geometric.html
*March 7, 2016*