Thursday

April 24, 2014

April 24, 2014

Total # Posts: 16,220

**7grade math**

I did it in the first line above: 6.75 (25/.75) = 225 miles

**7grade math**

6.75 (25/.75) = 225 miles You could have guessed which answer was right by doing 8 * 25 = 200 in your head. It is clearly not going to be less than 30 miles :)

**physics**

.92 * 97 = 89.24 97* 1000/3600 = 26.94 m/s 89.24 *1000/3600 = 24.79 m/s a = change in velocity/change in time how long to reach plate Vaverage = (26.94+24.79)/2 = 25.87 m/s so time to plate = 13/25.87 = .503 s so a = (24.79-26.94)/.503 = 4.27m/s^2 F = m a = .29(4.27) =1.24 N

**Intermediate Algebra**

Look at any of those examples down below. for example: http://www.jiskha.com/display.cgi?id=1294619397

**Math**

3 a + p = 10 o 6 o + a = p write as 3 a + 18 o = 3 p so now 3 a + p = 10 o 3 a + 18 o = 3 p ------------------subtract p - 18 o = 10 o - 3 p 4 p = 8 0 1 p = 2 o so two oranges balance a pineapple

**physical science**

F = m g = G M m/R^2 10 * R ---> 1/100 90 * m ----> 90 9.81 * 90/100 = 8.83 m/s^2

**physics**

NO WORK IS DONE TO MOVE HORizontaly !!!!!! there is no horizontal forCE !!! Do not be fooled !!! m g h = 1 * 9.81 * .51 = 5.00 Joules

**Math**

yes, 80

**Calculus**

now the hard way is v = Vi + a t 0 = 72 + a t a = -72/t x = Vi t + .5 a t^2 1/9 = 72 t + .5 (-72/t) (t^2) 1/9 = 72 t - .5(72 t) or like we said before 1/9 = (72/2) t

**Calculus**

LOL there is a hard way and an easy way the easy way is to know that during constant acceleration the average speed is the average of the beginning and end speeds average speed = 72/2 = 36 mph speed * time = distance 36 * time = 1/9 time = 1 hour/(9*36) 1 hour = 3600 seconds s...

**Math**

16 = 2*2*2*2 20 = 2*2*5 we need 4 twos and a five 16*5 = 80

**Math**

12 = 2*2*3 15 = 3 * 5 so we need two 2s a 3 and a 5 2*2*3*5 = 60

**Math**

smallest (or least I suppose :) usually it is called the least common multiple, or used to be.

**Calculus**

height of rectangle = z width of rectangle = b = base of triangle height of triangle = h length of side of triangle = sqrt[h^2+(.5b)^2] perimeter = p = 2 z + b + 2sqrt(h^2 +.25b^2) area = A = z b + (b/2) h = 200 yuuck

**Ficonacci puzzles**

1 1 2 3 5 8 13 21 34 ... take 2 3 5 -->10 , 9 take 3 5 8 ---> 24 , 25 take 5 8 13 ---> 65 , 64 take 8 13 21 --> 168 , 169 see a pattern ?

**Physical science**

Well, 0 Newtons gives 0 frictional force

**calc**

9 dy/dx = x^2 y^2 9 dy/y^2 = x^2 dx -9 / y = (1/3) x^3 + c when x = 3, y = 1 -9/1 = (1/3)(27) + c -9 = 9 + c c = -18 so -9/y = (1/3) x^3 + c if x = 3 * 3^(1/3) = 3^(4/3) then x^3 = 3^4 so -9/y = (1/3)* 3 * 3^3 - 18 -9/y = 27 - 18 = 9 -1/y = 1 y = -1

**Maths**

(1/9) sqrt 3 * sqrt 27 ? note 27 = 3^3 so sqrt 27 = 3^1.5 3^-2 * 3^.5 * 3^(1.5) = 3^-2 * 3^+2 = 3^0 = 1

**pre-calculas**

well, this one is different anyway -2 x^2 + 6 x + 5 = y find zeros x^2 - 3 y - 2.5 - -y/2 x^2 - 3 y = -y/2 + 5/2 x^2 -3 y + 9/4 = -2 y/4 + 10 y/4 + 9/4 (x- 3/2)^2 = -1/2 (y -19/2) when y = 0 (x-3/2)^2 = 19/4 so x = 3/2 +/- 1/2 sqrt 19 check with quad eqn x = [ -6 +/- sqrt (36 ...

**pre-calculas**

-(x+3)/(x-3)+(12x+4)/(x-3)(x+3) -2x/(x+3) LCD = (x+3)(x-3) which is (x^2-9) so -(x+3)(x+3)/LCD +(12x+4)/LCD- 2x(x-3)/LCD -x^2 - 6x - 9 + 12x + 4 -2x^2 + 6 x all over LCD (-3 x^2 + 12 x -5)/(x^2-9) check my arithmetic

**MORTGAGE**

128,000 * .8 = 102,400 principal p pmt = p [r/{ 1 -(1+r)^-n} ] n = 30 * 12 = 360 r = .085/12 = .00708333 1 + r = 1.00708333 (1 + r)^-360 = .07878669 1 - (1+r)^-360 = .9212133 .08 / .9212133 = .007689 times principal = $787.37

**pre-calculas**

multiply top and bottom by (x-5)(x+5) which is (x^2-25) x^2 - 9 x - 10 = (x-10)(x+1) by the way

**physics**

F = .0566 N still m = .733 a = F/m = .0772 1.44 = .5 (.0772) t^2 t = 6.11 s

**Physics**

We need to know its mass. Rearth = 6.380*10^6 meters Rorbit = 12.380*10^6 meters gain in potential energy + kinetic energy Potential: +G M m/rearth - G M m/rorbit = gain in potential energy Kinetic G M m/rorbit^2 = m V^2/rorbit V^2 = G M/rorbit Ke = (1/2) m V^2 add potential a...

**math**

LCD is 48 tuesday 14/48 wed 11/48 thurs 9/48 fri 6/48 total so far = 40/48 a) (9/48)100 = 18.75 % b) 48/48 - 40/48 = 8/48 = 1/6 c) (7/24)900 = 262.5 km

**Probability**

http://www.jiskha.com/display.cgi?id=1392506096

**Probability**

That is the way I listed them in my reply to you, but the column you use for each does not matter. In other words it does not matter what order you toss them, just toss each of them once. I headed the first column p the second n the third d

**Physics**

speed north = 30 - 130 sin 30 = -35 speed west = 130 cos 30 = 113 tan angle south of west = 35/113 so angle south of west = 17.2 deg so 270 - 17.2 = 253 on the compass rose

**Physics**

sine of slope angle = .195/1.36 = .143 angle = 8.24 degrees cos slope angle = .99 weight = 1.1 * 9.81 = 10.8 N component of weight down slope=10.8(.143) = 1.54 N a = F/m = 1.54 / 1.1 = 1.40 m/s^2 d = (1/2) a t^2 1.36 = (1/2)(1.40) t^2 t = 1.39 seconds

**Calculus**

dy/dx = slope = 1 - x/250 y = m x + 20 at tangent point y = (1-x/250) x + 20 = x - x^2/500 solve that for x

**Physics Help**

You forgot the weight weight = m g = 5(9.81) = 49 N so 100 N up, 49 down net force = 51 N up a = F/m 51/5 = 10.2 m/s^2

**Math help**

2 a - 1 b = 1 2 a + 6 b = 8 (multiplied eqn 2 by 2) -------------- subtract -7 b = -7 b = 1 then a = 1 ================================= -1 x + 1 y = 2 +2 x + 1 y = 8 ------------------subtract -3 x = -6 x = 2 then y = 4

**Math: Probablity**

p n d H H H H H T H T H H T T T H H T H T T T H T T T C two heads ---> 3 d P(HHT) = 1/8 e 3/8 f 4/8 = 1/2 g 2/8 = 1/4 h 6/8 = 3/4 i 1/8 j 1 k zero, not in set

**RE: Physics**

Sorry, sin not cos opposite / hypotenuse = sin 8.60 degrees

**physical**

m (4 m/s) = 600 kg m/s m = 150 kg

**physical**

original momentum in x direction = .4*3 - .8*2 = 1.2 -1.6 = -0.4 kg m/s so moves to left if first car was moving right final momentum in x direction = (1.2)v final momentum = original momentum (first law) 1.2 v = -0.4 v = - 1/3 meter/second

**Differential Equations**

(2y -x) dy = y dx 2 y dy - x dy = y dx 2 y dy = x dy + y dx y^2 = x y + c when x = 0 y^2 = c = 1 y^2 = x y + 1

**Physics**

cos (angle) = .178/1.19

**college math**

6 x^3 + 27 x^2 - 15 x ?? It is a cubic polynomial with one root at x = 0 and use the quadratic equation to find the other two.

**Astronomy**

because it is just barely above the horizon in the direction of the sun just as the sun set. See the reference I just gave you: http://www.cfa.harvard.edu/pao/skyreport/solar_system.html

**Astronmy**

Just about between us and the sun see http://www.cfa.harvard.edu/pao/skyreport/solar_system.html

**Differential Equations, Matrices**

cos45 -sin45 sin45 cos45 is 1/sqrt2 -1/sqrt 2 1/sqrt 2 1/sqrt 2 x' = x/sqrt2 - y/sqrt2 y' = x/sqrt2 + y/sqrt2 so x/sqrt2 + y/sqrt2 =3(x^2/2-2xy/2+y^2/2) +2 original vertex at (0,2) x' = 0 - 2/sqrt2 y' = 0 + 2/sqrt2 so (-sqrt 2 , sqrt 2) for (-1,5) x' = -1/s...

**Physics**

a = change in velocity/time a = (12-0)/ (177* 10^-3) = 67.8 m/s^2 distance = average velocity * time = 6 * 177*10^-3 = 1.06 meters F = m a m = 2.28/9.81 = .232 kg F = .232 * 67.8 = 15.7 horizontal force there is also a vertical force up by the pitcher = 2.28 to keep it horizon...

**physics**

v = omega R omega = (44.5 m/s) / (.385 m)

**perimeter**

outside dimensions = 28 by (x+8) garden dimensions = 20 by x concrete area = 28(x+8) - 20 x = 8 x + 224 cost = 88 (8 x + 224) = 704 x + 19712

**Advanced Maths**

QB = flow rate through big pipe QB = 1 res /t hours QS = flow rate through small pipe QS = 1 res / (t+3) hours 2 (QB+QS) = 1 res 2 [ 1/t + 1/(t+3) ] = 1 2(t+3) + 2 (t) = t^2 + 3 t 2 t + 6 + 2 t = t^2 + 3 t t^2 - t -6 = 0 (t-3)(t+2) = 0 t = 3

**Intermediate Algebra**

http://www.mathsisfun.com/data/grapher-equation.html

**Intermediate Algebra**

http://www.mathsisfun.com/data/grapher-equation.html

**Physics Total Mechanical Energy**

If it is at rest 50 m high, the total is m g h = 575 * 9.81 * 50 = 282,037 Joules The speed does not matter because we counted the total while at rest. However let's see ho much kinetic energy it has at the bottom (1/2) m v^2 = .5*575*31.3^2 = 281,660 Joules so to 3 signif...

**Math help polynomial**

Do operations inside parentheses first.

**Math help polynomial**

-3x(3 y^2) = -9 x y^2

**math**

http://www.jiskha.com/display.cgi?id=1392477199#1392477199.1392477396

**math**

no digit here is ten times another however 7,000 = 10 (700) and perhaps that is what the question means.

**physical science**

been there, scroll down

**physical science**

Vi up = 10 sin 60 = 8.66 m/s if ax is horizontal acceleration, there is none. Horizontal component of velocity is constant

**Math**

2^(x-1) = 3^(1-x) ????? (x-1) log 2 = (1-x) log 3 x log 2 - log 2 = log 3 - x log 3 x (log 2 + log 3) = log 3 - log 2 x = (log 3 - log 2)/(log 3 + log 2) you could look those up

**Math**

4 log x = log x * log x * log x log x * log x = 4 log x = 2 x = 10^2 = 100 if base 10 logs

**PHYICS**

Ac = v^2/R new Ac = (3 v)^2/R = 9 v^2/R 9 times :)

**physical sciences**

http://www.jiskha.com/display.cgi?id=1392457436

**PHYICS**

average angular velocity during stop = 45/2 = 22.5 rad/sec so total angle = 22.5 rad/s * 5 s = 112.5 radians 112.5 radians / 2 pi radians/revolution = 17.9 revolutions

**Physics**

m g h = increase of potential energy 80 * 9.81 * 10^3 = 785*10^3 Joules 785*10^3 = (1/4) total fuel energy burned so total fuel burned = 3.14 * 10^6 Joules 3.14 * 10^6 J / 37*10^6 J/kg = .085 kg

**Calculus 3**

I got sqrt 5 on the bottom

**Algebra**

10 log (2.4*10^-5/10^-16) 10 [ log 2.4 + log 10^11] 10 [11+.38] = 114

**Chemistry**

1 atm = 10.1 Newtons/cm^2 to find that type 1 atm = Newtons/cm^2 into a Google search box 10.1 Newtons/cm^2 * 17.5*10^3 cm^2 = 177,000 Newtons use the Google search box again: 177000 newtons = pounds and you will get back 39,791 pounds

**Simplify 2**

You are welcome :)

**Simplify 2**

19^.5 * 19^.5 = 19^(.5+.5) = 10^1 = 19

**Intermediate Algebra**

here is the method. Put your numbers in: http://www.jiskha.com/display.cgi?id=1294619397

**Physics**

u = 16.1 cos 44 = horizontal velocity the whole time Vi = 16.1 sin 44 = initial vertical velocity h = Hi + Vi t - 4.9 t^2 3 = 0 + Vi t - 4.9 t^2 4.9 t^2 - (16.1 sin 44) t + 3 = 0 solve quadratic for t, use the big one v = Vi - 9.8 t u = 16.1 cos 44 still speed^2 = u^2 + v^2

**Geometric Constructions HELP!**

well, wings are symmetrical port and starboard but not identical replacement cartridges for your printer. DVDs most replacement machinery parts for example new nut for bolt.

**Math**

f-g = -3 x +irrelevant - 9 x - irrelevant = -12 x + b slope = m = -12 Now you knew these last two perfectly well. Give your answer and let us just check.

**precal**

r = 16 , I assume grazes ground h = 16 - 16 cos T where T is angle up from straight down h = 16(1 - cos T) let's find out what angle hits 24 meters 24 = 16 (1 - cos T) 1.5 - 1 = - cos T cos T = -.5 T = 120 degrees so between 120 and (360 - 120) = 240 which is 120 or 1/3 of...

**Math**

constant slope is a straight line

**Math**

f*g = (x+4)(x-4) = x^2 -16 b) y = x^2 - 16 x^2 is always >/= 0 so smallest y is -16

**Ethics**

By the way you did not say if you were to pick only one. I am not sure I would count happiness as a moral value, although some would.

**Ethics**

1. yes, values 2. yes, physical strength

**Social Studies--Check My Answers Please--**

secede

**Check my work plz?**

#11 As far as I know they all are. #14 a square is a quadrilateral 4*90 = 360 I do not understand the earlier questions anyway.

**Check my work plz?**

#11 As far as I know they all are. #14 a square is a quadrilateral 4*90 = 360

**Math**

y = 5 x or any other linear function with finite slope y = x^3 or any other odd power of x

**Physics**

G (m )(4-m) /.25^2 = 2.5*10^-10 (4 m-m^2)=2.5*10^-10*.0625*10^11 /6.67 4 m - m^2 = .0234 * 10^1 = .234 m^2 - 4 m + .234 = 0 m = [ 4 +/- sqrt(16 - .0937) ]/2 = 2 +/- 1.997 so I suspect one of them is tiny and the other is about 4 .00293 and 3.997

**Math**

a) they are odd but 1/x is undefined at x = 0 b) linear but x is odd and |x| is even c) d/dx (2^x) = 2^x ln 2 so both derivatives keep repeating but sin x is periodic

**Calculus**

Note - I made a mistake in earlier problem, note correction, scroll down

**Calculus**

yes, that is where f(x) hits the x axis

**Math**

5 (25/12) = 125/12

**Math**

ok f'(x) = v(x) = .0015 x - .5825 at x = 100 v(x) = .15 -.5825 = -.4325 = -.43 dh/dt is negative, going downhill :)

**Math ???????**

hey - do you mean height OVER (meaning divided by) time or height as a function of time? If the latter, we need to take the derivative.

**Math**

-(5 f/6) > 6/3 we want to multiply both sides by -6/5 If we multiply by a negative, then arrow reverses f < (6/3)(-6/5) f < -36/15

**maths**

distance = rate * time 300 = 60 t t = 5 hours

**Pre-Cal**

I already did this today with a 7 minute period anyway They gave you PERIOD = 9 minutes Amplitude = wheel radius = 25 meters midline at 5 + 25 = 30 meters h = 30 - 25 cos (2 pi t/T )

**Math**

well wherever the derivative is zero, the INSTANTANEOUS rate of change is zero. That means whenever the cos x = 0 which is at pi/2 , 3pi/2 etc so those do work but..... HOWEVER the average change is zero between any two points a period apart in other words between x = 0 and x...

**whoops error**

a^2 + 4 a = -a -3 a^2 + 4 a + 3 = 0 a = [ -4 +/- sqrt (16-12)]/2 a = -2 +/- 1 a = -1 or -3

**Math**

You are welcome :)

**Math**

h(a) = a^2 + 3 a + 2 h(-3)= 9 - 9 + 2 h(a) -h(-3) = a^2 + 3 a so (a^2 + 3 a) /(a+3) = -1 a^2 + 3 a = -a - 3 a^2 + 4 a + 4 = 0 (a+2)(a+2) = 0 a = -2

**Math**

just for fun, let's see when v = 0 9.8 t = 23 t = 2.3 seconds at top so our problem is all on the way up. so h(2) = -4.9(4) + 23(2) + 2 h(1.5)=-4.9(2.25)+23(1.5) + 2 h(2)-h(1.5) = -4.9(4-2.25) + 23(.5) = 4.5 so v average = 4.5/.5 = 9 m/s part b well I already differentiate...

**Pre-Cal**

r = 20 period = 7 min = T when t = 0 h = 5 at t = 0 and wheel does rotation between h = 5 and h = 45 center at h = 25 so of form h = 25 - 20 cos (2 pi t/T )

**Algebra**

L = 2 x + 4 A = L w = (2x+4)(x+2) = 2 x^2 + 8 x + 8 using foil or use distributive property 2x(x+2) = 2 x^2 + 4 x 4 (x+2) = 4 x + 8 -------------------------add 2 x^2 + 8 x + 8 remarkable :)

**Physical Science Need Help Quick PLEASE:)**

Al;so go back and find I added to answers to your earlier questions

**Physical Science Need Help Quick PLEASE:)**

Newton - THIRD LAW use Google !!!!!

**physics**

High school texts --- BOO ! HEADING is the direction you point a boat or plane BEARING is the angle you measure to a lighthouse FROM your boat or plane. That said: V across = 2.11 V down stream = 1.84 |V| = sqrt (2.11^2 + 1.84^2) |V| = 2.8 m/s

**physics**

momentum at start = 0 momentum at end = .048*69.4 F = change in momentum/change in time (That is the original form Newton gave for the second law. If m is constant that is F=mA) = .048*69.4 / .00101 Newtons

Pages: <<Prev | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | **19** | 20 | 21 | 22 | 23 | 24 | 25 | Next>>