Thursday

July 28, 2016
Total # Posts: 26,569

**ap physics**

m2 g = m1 v^2/r
*January 18, 2016*

**AP Physics**

Vi = 4 sin 25 down so = -1.69 m/s u = 4 cos 25 forever = 3.63 m/s Hi = 1.2 h = Hi + Vi t -4.9 t^2 0 = 1.2 - 1.69 t - 4.9 t^2 4.9 t^2 + 1.69 t - 1.2 = 0 t = [ -1.69 +/- sqrt(2.86+23.5)]/9.81 t = .815 seconds d = u t = 3.63 * .815 = 2.96 meters
*January 18, 2016*

**check earlier volume of pipe **

Check earlier problem. diameter not radius was given
*January 18, 2016*

**Chemistry 101**

r = 6.5/2
*January 18, 2016*

**Physics**

same as any other distance = speed * time problem time = (.97/20) seconds of course we did not use the diameter bit but perhaps there is a part B ?
*January 18, 2016*

**Math**

You are welcome.
*January 18, 2016*

**Math**

ok BOTTOM/SIDE = bottom/side 9/x = 4/2 which happens to be what we did.
*January 18, 2016*

**Math**

well you do not show it but perhaps 4/2 = 9/x in which case x = 4.5 but I do not know what your triangles look like if the corresponding sides are not as I assumed then the right answer could be 18
*January 18, 2016*

**typo**

I mean -1/(-1/4) = +4
*January 18, 2016*

**Algebra (Urgent)**

the slope must be 1/(-1/4) which means m = +4 the first one is a yea y = +4 x - 2 the second one is a yes y = +4 x + 0 the third one is a no y = (1/4) x - 6 the fourth one is a yes y =+4 x + 3 Please check your reply Lady P
*January 18, 2016*

**Math**

3x+4 = 16 and 3x+4 = -16 x = 4 and x = -20/3
*January 18, 2016*

**Physics**

10.5 u = (10.5+104) v F = m a = -.658 m g so a = -.658(g) work done = F d = m (.658)(g) (6.66) work done = Ke after collision so (1/2) m v^2 = m(.658)(g)(6.66) v^2 = 2(.658)(g)(6.66) solve for v then u = (10.5+104) v/10.5
*January 18, 2016*

**MATHS**

a = X a r = X+1 so r = (X+1)/X a r^2 = X+4 so X [(X+1)/X ]^2 = X + 4 (1/X)(X^2 + 2 X + 1) = X + 4 X^2 + 2 X + 1 = X^2 + 4 X X = 1/2
*January 18, 2016*

**Math**

say base is a 6 by 6 square then 4 blocks will sit on it then another layer fits so 8
*January 18, 2016*

**Physics**

how long to fall from 50 m? h = (1/2) g t^2 t = sqrt (2 h/g) = srt (100/9.81) = 3.19 seconds d = u t = 40 * 3.19
*January 18, 2016*

**math multiply binomials by trinomials ( really need help)**

Now the only trinomial is at e) (x-2y)^2 = x^2 - 4 x y + 4 y^2 now we multiply that by (3x-6y) use distributive property (a+b)(c+d+e) = a(c+d+e) + b(c+d+e) so we have +(3x)(x^2 - 4 x y + 4 y^2) -(6y)(x^2 - 4 x y + 4 y^2) = +3 x^3 - 12 x^2y + 12 xy^2 -0 x^3 - 6 x^2 y + 24 xy^2...
*January 17, 2016*

**math multiply binomials by trinomials ( really need help)**

well, we do not need the distributive property if you know FOIL I do not dare to do a) because I do not know if you mean (1/5)x or 1/(5x) when you write 1/5x b) (2a-3)(2a-3) = 4 a^2 - 12 a + 9 -(3a+4)(3a-4)= -9 a^2 + 0 a +16 2(3a+1)(3a+1)= 18a^2 + 12 a + 2 add 13 a^2 + 27 etc
*January 17, 2016*

**Physics pleasse use ^**

Ms = 2.13 * 10^5 Me Me = Me Ms x = Me (d-x) x/(d-x) = Me/Ms = 1/ (2.13*10^5) x<<<< d so assume x/d = 1/(2.13*10^5) x = 7.87 *10^8/(2.13*10^5) x = 3.69 * 10^3 = 3690 km check 3690 is indeed <<<< 7870*10^5 :)
*January 17, 2016*

**Science Help**

The number of molecules and their mass does not change however the volume increases if the balloon expands so mass/ volume decreases
*January 17, 2016*

**algebra**

F = k * w * v^2 /R 182 = k (1800) (900)/600 k = .0674 F = .0674 (1800) (2025)/650 = 378 pounds
*January 17, 2016*

**math**

3/8 + 1/3 = 9/24 + 8/24 = 17/24 24/24 - 17/24 = 7/24 but are you sure you did not spend 1/3 OF THE REMAINDER on snacks?
*January 17, 2016*

**Calculus/ Application Of Derivative**

I get A = pi r^2 = 75 pi r = 5 sqrt 3 so dV = pi (75) dh dV/dt = 75 pi dh/dt so dh/dt = .5 m^3/min / (75 pi m^2) .5/(75 pi) = .00212 m/min
*January 17, 2016*

**Calculus/ Application Of Derivative**

http://www.jiskha.com/display.cgi?id=1453063814#1453063814.1453064668
*January 17, 2016*

**scroll down**

I JUST DID THIS !!!
*January 17, 2016*

**algebra**

d = k t^2 64 = k (2)^2 so k = 64/4 = 16 then d = 16 (15)^2 d = 16 * 225 d = 3600 feet ============ check g = 32 ft/s^2 h = (1/2) g t^2 = 16 t^2 yes
*January 17, 2016*

**History**

We seem to be talking about the era of Cyrus etc well, back then most religions had gods for just about everything.
*January 17, 2016*

**algebra 2**

we want 10 y in both so mutiply the whole first equation by 2 -12 x + 10 y = +8 +7 x - 10 y = -8 -----------------------add - 5 x = 0 well, x = 0 then 5 y = 4 so y = 4/5 or -10 y = -8 so again y = 4/5 (that was a check) the lines intersect at (0 , 4/5 )
*January 17, 2016*

**Maths**

Trick: at depth h the volume increase with delta h = the surface area * delta h draw that and remember it. surface area = pi r^2 what is r of surface at h = 5 ? that takes some geometry triangle from center 5^2 + r^2 = 10^2 r^2 = 75 r = 5 sqrt 3 so dV = pi (75) dh dV/dt = 75 ...
*January 17, 2016*

**I do not know**

rounding to what? nearest whole number (4,3) to one decimal place? ( 4.3 , 3.3 ) to two places (4.35 , 3.33) etc etc etc
*January 17, 2016*

**Math**

(0,0) is the origin. I do not know where you drew it on your piece of paper :) (it might be way over on the lower left :)
*January 17, 2016*

**math**

b/g = 8/7 so b = (8/7) g b + g = 195 (8/7) g + (7/7) g = 195 15 g = 7 * 195 g = 7 * 195 / 15 etc
*January 17, 2016*

**what?**

I can not figure out what you mean. y = 6 * 4^2x + 2 or y = 6 * 4^(2x + 2) or y = 6 * 4^2 * x + 2 or y = 6 * 4^2 * (x + 2) and none of the above ca be expressed as y = A b x as far as I know
*January 17, 2016*

**Physics**

The horizontal speed of the supplies during the fall is the airplane speed (if you drop a bomb, then turn, because if you go straight it hits under you :) so how long to fall 160 meters? (1/2) g t^2 = 60 t^2 = 120/g = 120/9.81 t = 3.5 seconds
*January 17, 2016*

**already answered**

heat depends how far vertically down the ramp d sin theta
*January 17, 2016*

**please define terms - typo???**

total cost ? = 1200 = 2 * 600 so q = 600 ? Total revenue? = 3 q = 1800 ?? Makes no sense Perhaps cost = 1,200 PLUS 2 Q ???
*January 17, 2016*

**for what**

6 a + 3 c = what is the question
*January 17, 2016*

**physics**

According to the de Broglie hypothesis, every object in the universe is a wave, a situation which gives rise to this phenomenon. The position of the particle is described by a wave function \Psi(x,t). The time-independent wave function of a single-moded plane wave of ...
*January 17, 2016*

**physics**

Look here maybe: http://en.wikipedia.org/wiki/Uncertainty_principle particularly the wave probability stuff.
*January 17, 2016*

**physics**

If you are into modern physics, there is a low but finite possibility of anything. In fact you might not be there where you think you are at all. Luckily you usually are on the same side of the wall you were before you did not move.
*January 17, 2016*

**Math**

Yes 80 gal * (8 pints/gal ) = 640 pints
*January 17, 2016*

**Math**

80 gallons is indeed more than 350 pints
*January 17, 2016*

**Math**

2/9 boys b 7/9 girls g b = (2/7) g or g = (7/2) b g - 250 = b (7/2) b - b = 250 (5/2) b = 250 5 b = 500 b = 100
*January 17, 2016*

**Math link to sinking fund formula**

for example http://www.math.utep.edu/Faculty/cmmundy/Math%201320/Worksheets/Sinking%20Funds%20&%20Annuities.pdf
*January 17, 2016*

**Math**

.052/4 = .013 = r so multiply by 1.013 every quarter year n = number of quarter years Google amount of a sinking fund S = 250 [(1+r)^n - 1 ] /r 6500 /250 = 26 = [(1+r)^n - 1 ] /r 26 = [ 1.013^n - 1 ]/.013 .338 = 1.013^n - 1 1.338 = 1.013^n so n log 1.013 = log 1.338 n (....
*January 17, 2016*

**Math**

Yes :)
*January 17, 2016*

**Math**

NO!!!! the whole point of my reply was .625 < .626
*January 17, 2016*

**Math**

but 5/8 = .625
*January 17, 2016*

**Maths lit, geography ,agricultural science. Life science**

How is a retired physicist in the United States supposed to be able to help with this? You must talk to the guidance person in your own school in your own country and follow your own wishes, not mine. If you have a math or physics problem, that is another matter :)
*January 17, 2016*

**math,eng,phy,chem,bio,geography,economics**

You used 8.99 - 3.65 = 5.34 g O2 for 8.99 g of Sc 5.34 + 8.99 = 14.33 g total Sc2O3 5.34 / 14.33 = .373 or 37.3 % ============================ check O3 = 3 * 16 = 48 Sc2 = 2 * 45 = 90 total molecular mass = 138 48/138 = .347 or 34.7 % looks like the experiment was a little off :)
*January 17, 2016*

**sorry, do not understand experiment**

What is the reaction you mean?
*January 17, 2016*

**Physics**

together we make 7+5 = 12 opposite we make 5-7 = -2
*January 17, 2016*

**Calculus**

eeewww http://www.wolframalpha.com/input/?i=plot+%282+%E2%88%92+x%29^%28e^%E2%88%92x%29+
*January 17, 2016*

**World history/ Latin America**

5. Phillipines ????? where are they?
*January 17, 2016*

**World history/ Latin America**

3. No
*January 17, 2016*

**World history/ Latin America**

2. NO !!!!!
*January 17, 2016*

**physics**

F = k Q1 Q2/d^2 for each we want x so F = 0 distances are x and from 2.4 and 1-x from -5.6 for F = 0 2.4/x^2 - 5.6/(1-x)^2 = 0 (NOTE - by inspection you can see that to get zero you must be left of the origin, negative x) if you locate so F = 0, then the electric field from ...
*January 17, 2016*

**Physics**

hen eggs have reasonable sigma. classroom chalk (I assume we are talking used chalk) has wild variation so would require far more observations and might eventually converge to a mean weight somewhat over half the weight new in the box.
*January 17, 2016*

**Physics**

vertical problem: s = muzzle velocity Vi = s sin 30 = s/2 u = s cos 30 = .866 s 7.8 = .866 s t where t is time in the air so s t = 9 t = 9/s h = Hi + Vi t -4.9 t^2 at ground h = Hi = 0 0 = 0 + (9)/2) - 4.9 (81/s^2) 4.5 = 396.9/s^2 s = 9.39 m/s Now you do all that for new s = 1...
*January 17, 2016*

**Math Teacher Certification Exam**

B = .02 + 2 (6.24) = .02 + 12.48 = 12.50 12.50 + 6.24 = $ 18.74 But beware. I am not certified to teach anything bur sailing!
*January 17, 2016*

**Math/ algebra**

area = A A/2 = pink Tulips (3/8) A = purple iris A/2 -(3/8) A = (1/8) A left (1/2)(1/8) A = 1/16 A = left so we want 1/16 You did fine (1/16)* 100 = 6.25 %
*January 17, 2016*

**Physics**

1.9 * 10^6 = 19 * 10^5 divide that by 1.7 * 10^5 the 10^5 cancels and the ratio of distance between to diameter is 19/1.7
*January 17, 2016*

**Physics**

19/1.7 = 11.2 11.2 * 26 = 290 cm = 2.9 meters
*January 17, 2016*

**world history**

agree, agree although oversimplified
*January 17, 2016*

**world history**

8. Is Taft 7. is income tax enough already, read this: http://quizlet.com/59801627/chapter-8-history-test-flash-cards/
*January 17, 2016*

**Physics**

.020 Cc (200 - T) = (.060 Cc + .050*4200) (T-30) where Cc is specific heat of copper in J/kg deg C
*January 17, 2016*

**trigo**

antenna height = h from roof up building height = b tan 42 10 = b/36 solve for b then tan 51 23 = (b+h) / 36
*January 17, 2016*

**math**

(.0025 /12)210,000 = $43.75
*January 17, 2016*

**math**

Hey, if you have a calculator, divide. If you do not, google calculator. Oh well 2/9 is much less than 4.4/9 which is 1/2 4/7 is bigger than 3.5/7 which is 1/2
*January 17, 2016*

**math**

0.85 * x = 45 so x = 45 / 0.85
*January 17, 2016*

**Calculus,Stationary Points,First derivative test**

You say dy/dx = 6(x^2 - x - 2) so the function is horizontal when (x-2)(x+1) = 0 or x = 2 and x = -1 Agreed NOW you can test it like you did, but usually what you do is take the second derivative. If it is +, the function is at the bottom and about to start up. If it is ...
*January 17, 2016*

**Maths**

Hey, try I will do D 3 sqrt 18 = 3 sqrt (9*2) = 3 sqrt (3*3*2) = 3*3 sqrt 2 = 9 sqrt 2 = 9 (1.414) around 12.5 or so which is between 12 and 13 NOW check that with your calculator (Google calculator if you do not have one on your desk) 3 sqrt(18) = 12.728
*January 17, 2016*

**ah I do not think so !**

8+3+5 = 16 not 11 so 3/16
*January 17, 2016*

**chemistry**

25 + 273 = 298 degrees Kelvin P V = n R T n and R are constant You do not mention P, so I guess maybe the pressure is constant? V/T = n R/P = constant so V1/T1 = V2/T2 T2 = (V2/V1) T1 T2 = .5 T1 = 298/2 = 149 K -273 + 149 = - 124 C That is wicked chilly.
*January 17, 2016*

**physics**

DRAW A PICTURE The way I am looking at it: speaker at x = -6 speaker at x = +6 wave from left at x = -6 moves right y = sin (w t - 2 pi x/L) wave from right at x = + 6 moves left y = sin (w t + 2 pi x/L) at x y=sin(wt-2pi x/L)+sin(wt+2pi x/L) = 2sin(wt)*cos(2 pi x/L) This is ...
*January 17, 2016*

**algebra ,**

ends in 5 or 0 odd, so ends in 5 100 a + 10 b + c We know c = 5 100 a + 10 b + 5 a b 5 = 15 or a b = 3 a + b <5 100a + 10 b < 144 so a = 1 since a b = 3, b = 3 so 135
*January 17, 2016*

**GCU**

Well, it does not, but anyway W = k * L 162 = k * 9 k = 162/9 then W = k * 8 W = (162/9) 8 W = 144 Problem is, unlike in math class, when you make a boat longer you have to make it stronger and wider and deeper so in real life it is closer to W = k * L^3
*January 17, 2016*

**Physics**

heat the ball warms up and the ground warms up, but not much :)
*January 17, 2016*

**geometry**

You are welcome.
*January 16, 2016*

**geometry**

there are 360 degrees in a circle there are 2 pi radians in a circle therefore: multiply radians by (180 deg/pi radians) to get degrees :)
*January 16, 2016*

**Mathematics**

dy/dx = [x^4 e^x - 4 x^3 e^x]/x^8 = [ x e^x - 4 e^x ] / x^5 = 0 when x = 4 increasing if x>4 decreasing if x <4 what is sign of second derivative? It is a pain to compute, sketch graph of slope' http://www.wolframalpha.com/input/?i=plot+[+x+e^x+-+4+e^x+]+%2F+x^5 sure...
*January 16, 2016*

**Math**

do you mean y = e^rx ? r^2 e^rx + 5 r e^rx + 6 e^rx = 0 r%2 + 5 r + 6 = 0 (r+3)(r+2) = 0 r = -3 or -2
*January 16, 2016*

**World History**

The wrong ones are so terribly, horribly wrong and the right one is horribly correct :(
*January 16, 2016*

**Math Terminology**

3 , 2 , and 7 are constants
*January 16, 2016*

**Algebra/math**

It is not possible for you to copy and paste to this site. Therefore we do not see your origimi.
*January 16, 2016*

**same gibberish. Read what you typed**

and also read my previous reply 5.11 %
*January 16, 2016*

**Math**

.1 * 23 = 2.3 half of that = 1.2 sum = 3.5 so I agree
*January 16, 2016*

**gibberish**

7000 days? 18 months? what are you talking about? anyway .05/12 = .004167 so every month multiply by 1.004167 so in twelve months v = Vi (1.004167)^12 v = Vi * 1.0511 or 5.11 percent annual interst
*January 16, 2016*

**TYPO muzzle speed far too low to ever work, wrong.**

Vi = initial up speed = ? cos A u = constant horizontal component = ? sin A s = horizontal airplane speed=340 T = flight time for both horizontal problem: 340 T = u T = ? T sin A so sin A = 340/(? ) which is kind of obvious :) now the vertical problem: h = 0 + Vi t -.49 t^2
*January 16, 2016*

**math**

v = 12,500 * .85^n
*January 16, 2016*

**math TYPO**

do you mean 40 cm^2 ? I will assume so A = (1/2) b h since it is 90 degrees, h is altitude , other leg 4 h = 40 h = 10 cm so we still need the hypotenuse c^2 = h^2 + b^2 = 100 + 64 = 164 = c = 2 sqrt (41) = 12.8 cm
*January 16, 2016*

**Math**

Lemme see 9 + 16 = 25 sure enough 2.5 * 9 + 3.25 * 16 = 74.5 which you could have done. If you are stuck, ask for help. If you need an answer checked, first check it.
*January 16, 2016*

**Geometry(Check My Answers)**

yes 30 + 75 + 75 = 180 You choice is ok the rest are not 7 and 13 will not reach 22 6 12 18 is a straight line again 13 + 8 = 21, will not reach
*January 15, 2016*

**Math**

3 + 16/25 = 3.64 3.64 * 100 = 364 yes, agree
*January 15, 2016*

**Geometry**

No, I can not explain that because I agree with you either by side angle side or as you said by the angles
*January 15, 2016*

**Mechanics(Ms.Sue)**

efficiency is maximum 100%, and that is impossible. Output less than input D is correct Yes !!! for speed you need a speedometer for velocity you need a speedometer AND a compass speed = scalar velocity = vector
*January 15, 2016*

**Math**

try 1600/75
*January 15, 2016*

**Math**

You do not get 85 if you divide 17 miles / 20 minutes You get 0.85 miles/minute mph is wrong here. Hours is not in the problem
*January 15, 2016*

**Careful !!**

2. x/5 + 6 = 10 a) 44 b) 30 <----------- c) 20 d) –20 ======================= x/5 = 4 x = 5 * 4 x = 20 I do not have time to look at all of them but for heavens sake try checking by substituting back in using x = 20 x/5 + 6 = 10 20/5 + 6 = 10 ? 4 + 6 = 10 YES - I got ...
*January 15, 2016*

**Quadratic Equation (math)**

well, 36 = 6^2 so try x^2 + b x + 36 = (x+6)^2 x^2 + b x + 36 = x^2 + 12 x + 36 so x^2 + 12 x + 36 ------------------- more officially (b/2)^2 = 36 b/2 = 6 b = 12
*January 15, 2016*

**Math**

150,000 $/sec * t sec = 3,000,000 t = 3,000 / 150 t = 20 seconds Again, nothing about minutes here, all is in seconds Of course we happen to know that 20 seconds is 1/3 of a minute :)
*January 15, 2016*