Sunday

February 7, 2016
Total # Posts: 25,150

**Math**

y = k x 7.5 = k (3) k = 7.5/3 = 2.5 = 5/2 (c) 10.4 = k (4) k = 10.4 /4 = 2.6 x
*December 3, 2015*

**Math Help!**

use t for x just like you would if they asked for f() or f(16) or whatever f(t) = 6 t - 2
*December 3, 2015*

**Algebra**

from (6,0) to (10,1) is up 1 and right 4 so slope = 1/4 so if 0 is not an answer, you have a typo
*December 3, 2015*

**Algebra**

90 miles in 1.5 hours yes 60 mph
*December 3, 2015*

**Algebra**

4. What is the slope of the line that passes through the points (4, 2) and (4, -3)? A. -1 B. 0 C. 1 D. Undefined ---------------------- denominator is 4-4 = 0 undefined (although actually that is just the vertical line x = 4)
*December 3, 2015*

**Algebra**

3. The pair of points (6,y) and (10,1) lies on a line with the slope 1/4. What is the value of y? A. -5 B. -2 C. 2 D. 5 ---------------- (1-y)/(10-6) = 1/4 so 1 - y = 1 y = 0
*December 3, 2015*

**Algebra**

2. A line has a slope -5/3. Through which two points could this line pass? A. (12, 13) and (17, 10) B. (16, 15) and (13, 10) *** C. (0, 7) and (3, 10) D. (11, 13) and (8, 18) (10-15)/(13-16) = POSITIVE 5/3 try D
*December 3, 2015*

**Math**

3 6 9 12 15 18 21 24 just keep adding 3 etc
*December 3, 2015*

**Mathematics**

2x - 1 = (7-4x) / (x-4) (2x-1)(x-4) = 7 - 4x 2 x^2 -9 x + 4 = 7 - 4 x 2 x^2 - 5 x - 3 = 0 (2 x +1)(x -3) = 0 x = 3 or x = -1/2 find y for each
*December 3, 2015*

**Chemistry**

.1667/.4168 = .400 is Carbon = 40% .2223/.4168 = .533 is Oxygen = 53.3 % so .067 is H = 6.7 %
*December 3, 2015*

**applied mechanics**

http://www.jiskha.com/
*December 3, 2015*

**applied mechanics**

You are given that 10 Newtons is the friction force you have to overcome.
*December 3, 2015*

**applied mechanics**

mu * weight = friction force mu = friction force / weight = 10/19.6 = .51
*December 3, 2015*

**applied mechanics**

I can not do that. I can only respond here.
*December 3, 2015*

**applied mechanics**

Started high school in 1951
*December 3, 2015*

**applied mechanics**

LOL, if I had one :) (but not allowed anyway)
*December 3, 2015*

**applied mechanics**

hummm mu is my English typing of the Greek letter for coef of friction coef of friction = .51
*December 3, 2015*

**applied mechanics**

weight = m g = 2*9.8 = 19.6 N mu * 19.6 = 10 mu = o,.51
*December 3, 2015*

**math**

Hard for me too. Can you give me an example of an easy one?
*December 3, 2015*

**precalc**

sketch it ! BC is only 4 long the others are longer than 4 but not the same
*December 3, 2015*

**math**

1/6 + 2/6 = 3/6 = 1/2 are red or blue the other half 3/7 (1/2) = 3/14 are green so 3/14 x = 27 1/14 x = 9 x = 14*9 =
*December 3, 2015*

**physics**

F = G m1 m2 / d^2 G = 6.67 * 10^-11 F = 6.67*10^-11 * 17.3 * 14.8 / 1.02^2 (not much :)
*December 3, 2015*

**Chemistry**

Huh ? subtract
*December 3, 2015*

**math**

h = -5 t^2 + 60 t + 15 at ground 0 = -5 t^2 + 60 t + 15 t^2 - 12 t - 3 = 0 t^2 -12 t = 3 t^2 - 12 t + 36 = 39 (t-6)^2 = 39 t - 6 = +/- sqrt 39 t = 6 + 6.24 = 12.24 seconds dh/dt = -10 t + 60 = -10(12.24) + 60 = -62.4 m/s dh/dt =-10 t + 60 at 2 seconds = -20 + 60 = 40 m/s
*December 3, 2015*

**math HEY sign Erropr !**

YOU have gravity reversed !!!! the building is 15 meters high since that is h when t = 0
*December 3, 2015*

**Algebra**

pool area = 54 whole thing L = 9+2s w = 6+2s area of whole thing = (9+2s)(6+2s) so (9+2s)(6+2s) = 2 * 54 = 108 54 + 30 s + 4 s^2 - 108 = 0 4 s^2 + 30 s - 54 = 0 2 s^2 + 15 s - 27 = 0 (2s-3)(s+9) = 0 s = 3/2 = 1.5
*December 3, 2015*

**PreCalculas check**

That is not a parabola! (y-k) should not be squared should be upside down parabola, sheds water form (x-h)^2 = 4 a (y-k) (x-2)^2 = 4a (y-5) a = vertex to focus = 8 (x-2)^2 = -32(y-5) - 32 because sheds water. as x gets big, y goes to - infinity
*December 3, 2015*

**Applied Mechanics**

normal force = m g = 4*9.81 friction force = .4 * 4 * 9.81 = answer in Newtons
*December 3, 2015*

**maths**

g = b + 12 b+12 = .65 (b+12+b) b + 12 = .65 (2 b) + 7.8 4.2 = .3 b b = 14
*December 3, 2015*

**math**

LOL - I am really not paying attention and missed the pattern note that except for 1/4, the numerator is always one less than the denominator therefore 1 - the fraction keeps getting lees and the fraction gets bigger as the numerator and denominator get bigger I mean obviously...
*December 3, 2015*

**math**

well the really easy way is to convert to decimals but we should do it the hard way I suppose for LCD we need three twos for 8 and a three and a five so 8 * 3 * 5 = 120 , ah well 1/2 = 60/120 4/5 = 96/120 5/6 = 100/120 2/3 = 80/120 7/8 = 105/120 1/4 = 30/120 Now you can do it :)
*December 3, 2015*

**Math**

-2x+y=1 -4x+y=-1 ------------ subtract because coefficient of y is the same -2x + 4x + 0 = 1+1 = 2 2 x = 2 x = 1 then -2(1) + y = 1 y = 3 so in the end (1,3)
*December 3, 2015*

**Pre calculus**

You are welcome.
*December 3, 2015*

**Pre calculus**

the slope is: (-6 - -7) / (-8 - -5) = 1/-3 = -1/3 the slope is also (y - -7) / (x - -5) = (y+7)/(x+5) so (y+7) = (x+5)(-1/3)
*December 3, 2015*

**Simple pre cal**

There are two values of y for z = 15 !
*December 3, 2015*

**Physics**

Instead of 90 degrees to the shaft (optimal) You are at 120 which is 30 degrees off. so your force perpendicular to the shaft is F cos 30 The torque is F cos 30 * 0.39 so F cos 30 * 0.390 = 49.0
*December 3, 2015*

**Physics**

http://www.jiskha.com/display.cgi?id=1449174010
*December 3, 2015*

**Mathematics**

new length and width = 19-2x area of base = (19-2x)^2 height = x so V = x (19-2x)^2
*December 3, 2015*

**Social Studies**

Lots of things like languages and foods and religions and boat designs. Did you mean to post a list?
*December 3, 2015*

**Easy math question**

7 x = 2 y + 5 2 y = 7 x - 5 y = (7x-5)/2
*December 3, 2015*

**math**

Speedy d at 110 and d at 130 t = d/110 + d/130 = d(.01678) Cannon 2 d at 120 t = 2 d/120 = d/60 = d(.01667) Speedy's time is bigger, he lost
*December 3, 2015*

**typo**

so c = -20 I do not know why I said that, typo while copying and pasting
*December 3, 2015*

**Algebra 2 (Math)**

a x^2 + b x + c (1) a(4) + b(-2) + c = -20 (2) a(0) + b(0) + c = -4 (3) a(16) + b(4) + c = -20 -------------------------------- eqn (2) tells us that c = -4 so c = -20 (1) a(4) + b(-2) = -16 (2) a(0) + b(0) = 0 (3) a(16) + b(4) = -16 ------------------------------ (1) -8 a + 4...
*December 3, 2015*

**Physics**

This is the same as the one with the skaters, just different numbers momentum before = .255 v + .365 * 0 momentum after = .255 (-.118) + .365*.649 momentum after = momentum before, solve for v
*December 3, 2015*

**Pre calculus**

That is a straight line with slope -2, it has perfectly finite values for any real x so B
*December 3, 2015*

**algebra**

for example: http://ncalculators.com/statistics/linear-regression-calculator.htm
*December 3, 2015*

**algebra**

google linear regression to get software calculator to fit straight line to your data.
*December 3, 2015*

**Physics**

momentum is zero before so zero after. 61*.63 + m* -.86 = 0 note speeds are opposite so velocity of one or the other is negative m = 61 (.63/.86)
*December 3, 2015*

**Math**

12 * 3 / 4 = 3*3 = 9
*December 3, 2015*

**Maths**

2 w + 2 (w+5) = 26 2 w + 5 = 13 2 w = 8 w = 4 w+5 = 9
*December 3, 2015*

**Please Check My Work: College Physics**

N is normal force from road m g = N cos T so N = m g/cos T N has inward component = N sin T so inward component of force = m g sin T/cosT = m g tan T Ac = m v^2/R m g tan T = m v^2/R tan T = v^2/( Rg) as you know tan T = 400/(200*9.81) tan T = .204 T = 11.5 degrees
*December 3, 2015*

**Please Check: College Physics**

You are welcome.
*December 3, 2015*

**Huh ? horizontal, no g , friction force - 12**

F = m a -12 = 8 a a = -1.5 m/s^2 yes 0 = 6^2 + 2 a x 0 = 36 -3 x x = 12 m
*December 3, 2015*

**sms**

1.44/16
*December 3, 2015*

**History**

I would also choose A although he did want to get home.
*December 3, 2015*

**math/technology**

If there are two there are two.
*December 3, 2015*

**physics**

2 kg * 9.81 = 19.62 N weight loses (19.62-12.34) = 7.28 N in water 7.28 N /9.81 = .7421 Kg of water displace .7421 kg * 1 m^3/1000 kg = 7.421 * 10^-4 m^3 = volume of mass mass of light fluid displaced = 7.421 *10^-4 m^3 * .78 * 10^3 = .579 kg weight of light fluid displaced...
*December 3, 2015*

**calculus**

MITx question ?
*December 2, 2015*

**prealgebra**

w and w+3 perimeter = 2 w + 2 (w +3) = 58 4 w + 6 = 58 4 w = 52 w = 13 so 13 by 16
*December 2, 2015*

**Precalculus**

2(1-sin^2 T) + sin T = 1 2 - 2 sin^2 T +sin T - 1 = 0 -2 sin^2 T + sin T +1 = 0 2 sin^2 T - sin T - 1 = 0 let z = sin T 2 z^2 - z - 1 = 0 (2 z +1)(z-1) = 0 z = -1/2 or z = 1 so sin T = -1/2 gives T = 150 deg or -30 deg sin T = 1 at 90 deg
*December 2, 2015*

**Calc 3**

Do you know about divergence and curl ? I have a sneaking suspicion that the divergence and curl (no sources or sinks and no vortices with singularities at the origin) are zero and the flux and line integral around the closed surface are zero.
*December 2, 2015*

**math**

12 by 8 by 5 five is the height because in vertical plane. 12 by 8 is the top and bottom. Sketch a drawing of it !
*December 2, 2015*

**chem.**

Fe = 56 g/mol 3 O = 3*16 = 48 g/mol so a mol of Fe2O3 is 160 grams and a mol of Fe is 56 grams 3 g Fe = 3/56 mol Fe that will give me half as many mols of Fe2O3 so 3/112 mols Fe2O3 (3/112) * 160 = 4.29 grams of Fe2O3 ========================
*December 2, 2015*

**Physics**

force = change on momentum/change in time = .045 * 59 / .001 = 2655 Newtons
*December 2, 2015*

**MATH SUPER URGENT!**

50 * 20 = 1000 strip width = s interior dimensions (50-2s)(20-2s) = half original = 500 1000 - 140 s + 4 s^2 = 500 so 4 s^2 - 140 s +500 = 0 s^2 - 35 s + 125 = 0 s = [35 +/- sqrt (1225-500) ]/2 s = [35+/- 26.92 ] /2 s = 30.96 or 4.04 must be 4.04 because strips of 31 each end...
*December 2, 2015*

**Algebra**

d = 100 - q 25 q + 10 d = 2140 25 q + 1000 -10 q = 2140 15 q = 1140 q = 76 so d = 24
*December 2, 2015*

**Social studies**

nope, which is not an advance in technology but simply something you do.
*December 2, 2015*

**algebra**

Huh, what you typed is not true.
*December 2, 2015*

**Algebra**

2x -5x -11 >/= 4x + 17 -3x >/= 4x + 17 0 >/= 7x + 17 7x </= -17 x </= -17/7
*December 2, 2015*

**Pre Calc**

http://www.jiskha.com/display.cgi?id=1449008243
*December 2, 2015*

**Pre Calc**

I think I did this yesterday 5, 12, 13 triangle cos^2 - sin^2
*December 2, 2015*

**MATH**

8 log5(x) + 4 log5(y)
*December 2, 2015*

**MATH**

log5 (x^2y)^4 4 log5(x^2y) 4 [ log5 (x^2)+ log ( y) ] 4 [ 2 log5 (x)+ log ( y) ]
*December 2, 2015*

**science**

By the way I did all this as if a kg was a force If you need Newtons and Newton meters, multiply final answers by 9.81
*December 2, 2015*

**science**

get end forces up first beam kg = 6*1500 = 9000 kg at center forces F1 up at left and F2 up at right moments about left to get F2 F2*6 = 1000*1.5 + 11000*3 + 3000*4.5 so F2 = 48,000/6 = 8,000 up at right end total mass = (1+11+3)10^3 = 15,000 kg so F1 = 15,000- 8000 = 7,000 up...
*December 2, 2015*

**math**

2w+2L any old whole numbers for L and w
*December 2, 2015*

**algebra please explain**

-3
*December 2, 2015*

**math**

125,000 - 125,000 = 0
*December 2, 2015*

**Mathematics**

mean = 165 defective if <156.2 variance = 16 so sigma = sqrt 16 = 4 (did you notice that?) then use Davidlane http://davidmlane.com/hyperstat/z_table.html I get 0.0139 or 1.39 percent
*December 2, 2015*

**Mathematics**

mean = 165 defective if <156.2 variance = 16 so sigma = sqrt 16 = 4 (did you notice that?) then use Davidlane
*December 2, 2015*

**Social Studies**

true, Nederlands
*December 2, 2015*

**Social Studies**

yes
*December 2, 2015*

**Social Studies**

as I remember you are right :)
*December 2, 2015*

**Science**

how wide has nothing to do with this Upstream speed = 8.9 sin T - 2.4 if we do not want to go upstream, that must be zero so 8.9 sin T = 2.4 T = 15.6 degrees
*December 2, 2015*

**Social Studies**

yes, Catholic
*December 2, 2015*

**Social Studies**

Yes, center is Andes and Jungle :)
*December 2, 2015*

**Social Studies**

No idea, assume you know
*December 2, 2015*

**Social Studies**

yes, that is what missionaries do.
*December 2, 2015*

**Math**

Amy if there are F friends, then each gets 40/F say you had 4 people and 40 grapes each would get n = 40/4 = 10 grapes
*December 2, 2015*

**Math**

n = 40/f
*December 2, 2015*

**Physics**

20 * x = 10 (1.08 -x) 20 x + 10 x = 10.8 30 x = 10.8 x = .36 so .36*10^-10 = 3.6 * 10^-11 meters
*December 2, 2015*

**History**

There were no term limits for presidents when I started voting. That was after George Washington rode off into the sunset. He did start a tradition of term limits, but there was no law and in fact FDR served more than two before and during WW2.
*December 2, 2015*

**Algebra 2**

log3 (x) = 9 well what I would do is 3^(log3(x)) = x = 3^9 same for #2 3) e^lnx = x = e^2 Just one more step from what you showed
*December 2, 2015*

**math**

6.3
*December 2, 2015*

**Math - are you sure?**

Do you really mean? x+2y+z=1 -x+y+0z=4 4x-0y+3z=-1
*December 2, 2015*

**Physics**

Hi = 1.6 u = 6.4 cos 65 forever = x coordinate Vi = 6.4 sin 65 initial Vertical problem: v = Vi - 9.81 t h = Hi + Vi t - 4.9 t^2 so 0 = 1.6 + 5.8 t - 4.9 t^2 or 4.9 t^2 - 5.8 t - 1.6 = 0 t = [ 5.8 +/- sqrt (33.64 + 31.36)]/9.8 t = (5.8 +/- 8.06)/9.8 we want + answer t = 1.41 ...
*December 2, 2015*

**Maths**

x^2 = 2 y x = +/- sqrt (2y)
*December 2, 2015*

**7th Math**

Er 1.7 *10^22 P 1.3*10^22 Ha 4*10^21 Ma 3*10^21 Ce 9 * 10^20
*December 2, 2015*

**7th Math**

You are welcome.
*December 2, 2015*

**7th Math**

1. right 2. right , right
*December 2, 2015*