Saturday

April 19, 2014

April 19, 2014

Total # Posts: 16,161

**Calculus**

perpendicular to the direction 1 i - 1 j + 2 k Vxi + Vyj + Vzk if perpendicular dot product is 0 Vx - Vy + 2 Vz = 0 also parallel to plane x+y+z = constant 2 so normal to the normal to that plane 1 i + 1 j + 1 k Vxi + Vyj + Vzk Vx + Vy + Vz = 0 so we have Vx - Vy + 2 Vz = 0 Vx...

**Calculus**

going from the first point to the second dx = 3 dy = -2 dz = 4 so my line direction is 3 i -2 j + 4 k and my line in parametric form is (1,0,1) + (3, -2, 4) t at intersection x = 1+3t y = -2 t z = 1+4t and we know x + y + z = 10 2 + 5 t = 10 t = 8/5 so x = 1 + 24/5 = 29/5 y = ...

**Calculus**

(1+4t) +2 (4t) -(2-3t) = -1 solve for t then use that t to find x, y z

**Calculus**

see http://www.jiskha.com/display.cgi?id=1391198824 for the method

**Calculus**

we have two points in that plane (8, 0, -2) and (6, 3, 3) a vector through those points has direction (6-8)i + 3 j + (2+2)k = -2 i + 3 j + 4 k so we have two vectors parallel to plane, their cross product is normal to the plane i j k -2 5 2 the given line direction -2 3 4 the ...

**math**

original p = 2 w + 2 L final p = 2 (3w) + 2 (2L) 2 (3w) + 2 (2L) = 92 + 2 w + 2 L 3 w + 2 L = 46 + w + L 2 w + L = 46 That is all I can say unless I know something more, for example that the original or final rectangle is a square.

**physics**

force = rate of change of momentum change of velocity = 15+17.4 = 32.4 m/s rate of change of momentum = mass per second * change of velocity = 33.6 kg/s * 32.4 m/s = 1089 kg m/s^2 or Newtons

**Math palette of problems**

(2/9) gal / (3/5) buc = x gal/1 buc multiply top and bottom of left fraction by 45 10 gal/27 buc = x gal/1 buc 10 gal = 27 buckets 10/27 gal = 1 bucket

**pre cal**

See below http://www.jiskha.com/display.cgi?id=1391134584#1391134584.1391136919

**Math Pre-Cal**

2 x^2 -12 x - 6 = y x^2 - 6 x - 3 = y/2 x^2 - 6x = y/2 + 3 x^2 - 6 x + 9 = y/2 + 12 (x-3)^2 = (1/2)(y + 24) vertex at x = 3 and y = -24

**Math Pre-Cal**

to do it with algebra, complete the square

**Math Pre-Cal**

If you do know calculus, find the derivative and set it equal to zero (the slope is 0 at a max or min) 4 x -12 = 0 so x = 3 then y = 2x^2-12x-6 = 2(9) -12(3) -6 =18 - 36 - 6 = -24 that vertex is a minimum because y gets big as x gets big

**Math Pre-Cal**

If you do not know calculus you must find the vertex of that parabola.

**Math help**

If you know that x = 3 for example Then use 3 instead of x in the next equation and all will be well.

**Math**

(x-p)(x-q) = x^2 + b x + 12 p q = 12 b = +/-(p+q) p and q must be the same sign and product 12 so 1) p = 1, q = 12 2) p = 3, q = 4 3) p = -1 , q = -12 4) p = -3, q = -4 so b = 13 b = -13 b = 7 b = -7 try those x^2 + 13 x + 12 = (x+12)(x+1) x^2 - 13 x + 12 = (x-12)(x-1) x^2 + 7...

**English**

You are welcome :)

**English**

inflicts I think

**math**

assuming they all eat lunch and 75% buy their lunch then 25% bring their own lunch .25 * 480 = 120 bring lunch

**Social studies**

we agree about 2 because I think railways were just a few years later but the last one is surely Adams-Onis which settled the matter of Florida and the west to California with Spain at least for the time being.

**Social studies**

The Munroe Doctrine was around 1823 I think.

**Social studies**

The Erie Canal certainly increased the population of New York and accelerated it beyond Philadelphia and Boston but as far as the entire northeast is concerned I would pick growth of factories and trade throughout the region.

**Physics**

T = 2 pi sqrt (L/g) 3.3 = 2 pi sqrt (1.5/g) sqrt(1.5/g)= .5252 1.5/g = .276 g = 5.44 m/s^2 around half earth g

**Calculus**

l) (g)^2 + (h)^2=1 so 2 g g' + 2 h h' = 0 g g' = -h h' g' = -(h/g) h' 2)g' = h^2 and h' = -g g'/h h' = - g h^2/h = -gh that is part a then If h has a max, then h' has a zero - g h = 0 ? either g = 0 or h = 0 if h is max, look for zer...

**Physics**

time in air = 3.33 so time ascending = 3.33/2 = 1.665 v = 0 at top = Vi - 9.81 (1.665) so Vi = 16.3 m/s average speed up = 16.3/2 time up = 1.665 so distance up = 13.6 meters

**science**

By the way, if the ship had a hole in the bottom, so that it filled with water, it would sink just like the nail.

**science**

Archimedes says: Force up on ship or nail - weight of water displaced which is density of water times g times VOLUME OF WATER DISPLACED. In the case of the ship, assuming it is not full of water, the volume of water displaced includes the volume of the inside of the hull which...

**science**

Hey, many of these are trivial and I am sure you do not need our help with them. Please just post the ones you are having trouble with and show your attempt at solutions.

**math**

yes, 100 * 100 = 10^4 = 10,000

**Finite Math**

The break even point is where the revenue equals the cost 290 x = 250 x + 5000 40 x = 5000 x = 125 so 125,000 beanie babies

**math**

hypotenuse

**math**

well, easy think of some 1/2 + 1/2 = 2/2 = 1 1/3 + 2/3 = 3/3 = 1 sum of tops must equal denominator when denominators are the same that means you need to put them over a common denominator, but you have to do that to add them anyway.

**Math/Algebra**

10 + .4*5 = 12 10 + .4*8 = 13.2 10 + .4*4 = 11.6 it may be bumpy but: There is one and only one output value for every input value. Therefore it is a function.

**Calculus**

c) as t --->oo v ---->1/t = 0 d) 500 = 5 + .5 ln (t^2+1) 495 (2) = ln(t^2+1) 990 = ln (t^2+1) e^(990) = t^2 + 1 oh, my, calculator overflow :)

**Calculus**

dx/dt = t/(1+t^2) that will be maximum when the derivative d^2x/dt^2 = 0 d^2x/dt^2 = [(1+t^2)1 -t(2t) ](1+t^2)^2 0 when numerator is zero 0 = 1 + t^2 - 2 t^2 0 = 1 - t^2 t^2 = 1 so max or min at t = 1 we know it is max because v decreases with big x a ) so max v = 1/2 at t = 1...

**Finite Math**

a) 5,000 no matter how many b) 250/1000 for each c) 250 (100) + 5000 = d) answer to c) / 100,000

**Linear Algebra!**

I could also say the dot product of vector 1 and vector 2 is 0 if they are perpendicular V1 = 1 i - 2 j V2 = a i + b j V1 dot V2 = a -2 b = 0 so no matter what t is, a = 2 b V2 = 2 i + 1 j or 4 i + 2 j or in general V2 = (2 i + 1 j) t

**Linear Algebra!**

1 i - 2 j slope = -2 our slope = -1/-2 = 1/2 vector direction = 2 i + 1 j so r = (1i +0j) + (2 i + j) t

**Calculus**

dy/dx = 2/2 = 1 so y = x + b 0 = 3 + b b = -3 so y = x - 3 if x(t) = k t for example then y(t) = x(t) - 3 y(t) = k t - 3

**physics**

(1/2) m v^2 = m g h v^2 = 2 g h v^2 = 2 * 9.81* 1.36 v = 5.17 m/s so the change in velocity from top to bottom is 5.17 acceleration is constant so average speed = 5.17/2 = 2.58 m/s so it took 3.6 /2.58 = 1.39 seconds for the block to get down the slope the velocity changed fro...

**Math**

well, we know that both are y so 6x-5 = -x+9 7 x = 14 x = 2 then y = -x+9 = -2+9 = 7

**Social Studies**

I would not blame Hitler on his childhood myself. However I might look at his First World War experiences closely.

**Physics**

8.01 ?

**am history**

Shiloh It was only a surprise to Grant.

**math**

well, look here: http://www.mathsisfun.com/geometry/interior-angles-polygons.html

**MATH**

cars generally run on burning fossil fuel (gasoline, diesel) but even if they run on electricity they increase the effect two ways at least: 1. The elctricity is often generated by burning coal or oil. 2. Even if the electricity is generated using wind or solar power or water ...

**physics**

Look at this hint (not far off my guess :) http://www.jiskha.com/display.cgi?id=1354300345

**physics**

baking soda ? I have no idea what you are supposed to say.

**Math**

if you multiply the scale of the pattern by 2.5 you multiply every dimension by 2.5 However if by 2.5 times bigger you mean the AREA is 2.5 times bigger then you multiply every dimension by the square root of 2.5. I doubt is this is what she means.

**English**

been there, done that :)

**English**

Her body slumped against the classroom wall beside the door hoping for the bell to ring.

**science(1answer)**

Oh sorry, slightly different, train going v for train (1/2) m v^2 = 5,000 * 10^2 for car (1/2) m v^2 = 1300 * 4 * 10^2 = 5,200 * 10^2 so now it is the car number A

**science(1answer)**

Now really, I have replied three times now. Yes http://www.jiskha.com/display.cgi?id=1391014223

**physic**

Yes, I get 2.86 * 10^-6

**physic**

I already replied http://www.jiskha.com/display.cgi?id=1391014223

**Science**

v = Vi - g t 0 = 20 - 9.81 t at top when v = 0 t = 2.04 seconds h = 12 + Vi t -(1/2) g t^2 h = 12 + 20(2.04) -4.9(2.04)^2 h = 32.4 meters

**science (check answers)**

http://www.jiskha.com/display.cgi?id=1391017066

**science (check answers)**

I thought I already replied to this

**Physics**

C of water is 1 calorie/gram deg C 400 = 1 * 40 (T-20) 10 = T-20 T = 30

**Math**

1 /(1/3) multiply top and bottom by 3 3 / (3/3) = 3/1 = 3

**science(check answers)**

(1/2) m v^2 is certainly bigger for the train because (1/2) is the same and v^2 is the same but m is MUCH MUCH bigger so I agree, B

**Math**

You need the specific heat of water in BTU per gallon deg F Well the specific heat of water is ONE BTU per POUND deg F and a gallon is about 8.33 pounds of water so C = 8.33 BTU/(gal deg F) SO WE NEED btu = 8.33 * 30 * 70 = 17496 btu 17497 BTU = 25000 t so t = 0.7 hours or 42 ...

**social studies---check 1 question pls**

Samuel Slater did the first spinning mill in the USA and is usually called the father of the American industrial revolution. Francis Lowell started the corporate mill factory system. I think the question could be worded better but think you are right to choose Lowell (besides,...

**social studies---check 1 question pls**

agree

**science(check answers)**

(1/2) m v^2 = 30*900 = 27,000 Joules That is C !!!!

**Physics**

v = Vi + a t 17.9 = 6.6 + 2.3 t

**physic**

F = k q^2/(.5)^2 = m g sin theta where theta is angle from vertical tan theta = theta in radians = sin theta for small angle = .25 m (half of distance between)/2.5 = 0.1 so q^2 = .5^2 (.3)(9.81)(0.1)/(9*10^9)

**math**

180 - 110 = 70 6 - 6/4 - 6/3 - 6/8 = 1.75 yes 0.25 22.5 * 4 = 90 yes

**Math- Vectors**

V2 = 3 i + 7 j + 1 k find vector perpendicular to that V3 = Vx i + Vy j + Vz k if perpendicular then V3 * V2 = 0 3 Vx + 7 Vy + 1 Vz = 0 or Vz = -(3Vx+7Vy) now that vector has to go through the points where y and z are 0 for L1 if y = 0 t = 1/2 and L1 = [3+2 , 5-5 , -1 +1] = [5...

**physics**

y = Yo + Vi t - (1/2)gt^2 g = 9.8 so (1/2) g = 4.9 so the last term has to be -4,9 t^2

**Physics**

By the way, since you set out every other needed step for a solution in your problem statement I assume you do not know how to convert miles to kilometers. One very crude way is to remember that 30 miles per hour is about 50 kilometers per hour but even easier and more accurat...

**Physics**

Radius of earth = 6,371 kilometers 248 miles = 399 kilometers so r = 6371+399 = 6770 100 (6371/6770)^2 = 88.6 %

**fractions as division word problems**

2/5 = 4/10 = 0.4

**math**

to multiply by 100 move your decimal point two places to the right 53.33 * 100 = 5333

**Algebra 1**

Radius = r = 3 ft, height = 1.5 ft volume = pi r^2 h = pi (9)(1.5) = 42.4 ft^3

**Math help**

2) -2x+3y=11 X=4y-3 -2 (4y-3) + 3 y = 11 -8 y + 6 + 3 y = 11 - 5 y + 6 = 11 -5y = 5 y=-1 etc

**Math help**

1) use 5 y - 1 for x so 5 y-1 + 2y = 13 or 7 y - 1 = 13 7 y = 14 y = 2 now go back and get x x = 5(2)-1 x = 9

**Math help**

1) use 5 y - 1 for x so 5 y-1 + 2y = 13 or 7 y - 1 = 13 7 y = 14 y = 2 now go back and get x x = 5(2)-1 x = 9

**Math**

An = 2^n Yes, correct A1 = 2 r = -3 yes, correct

**algebra 1**

You are welcome :)

**algebra 1**

pi (2.25 -1) = 1.25 pi = 3.93

**algebra 1**

R = 1.5 r = 1 pi R^2 - pi r^2 pi (1.5)^2 - pi (1)^2

**Vectors**

ok weight = m g = 9.81 m 9.81 m sin (Theta) = 215 N where Theta is the angle of the ramp up from horizontal

**Vectors**

We need to know the slope of the ramp, if friction is important, and if the object is on earth.

**Math**

You are welcome :)

**Math**

least common multiple of 6 and 8 is 24 teeth clashing that is 4 turns of the 6 and 3 turns of the 8

**physics**

The wording of this question puzzles me because if they are in orbit they feel no gravitational force since the centripetal acceleration (v^2/R) exactly balances earth gravity. However if you wish to separate out those two factors then use Forbit = G m Me / Rorbit^2 Fground = ...

**I do not understand**

do you have a typo or is that something I just do not know about?

**calc**

z = 2 cosine 60 + 2 i sin 60 z= 2 e^i(60) z^4 = 16 e^i(240) = 16 cos 240 + 16 i sin 240 = 16 (-.5 )+ 16 i(-.866 ) = -8 - 13.86 i

**physics**

in degrees or radians? 1.834 degrees or .032 radians note, for small angles sin (Theta) = Theta in radians

**Math**

yes, use x

**Math**

if i </= 20,000 tax = .15 * i if i> 20,000 tax = 3,000 + 0.20 ( i - 20,000)

**chemistry**

NaNO3 Na = 23 N = 14 O3 = 3*16 = 48 total = 85 Na = 100 * 23/85 N = 100 * 14/85 O3 = 100 * 48/85

**Physics**

I will assume the inclined block wins and slips down the hill Force up on inclined block = T force down slope on inclined block = 28 (9.81 )sin 53 - 28 (9.81)(.9)cos53 a = acceleration down slope 28 a = 28 (9.81 )sin 53 - 28 (9.81)(.9)cos53 - T Force down on hang mass = m g = ...

**physics**

wires are 60 degrees from vertical so T cos 60 = 110 T (1/2) = 110 T = 220 N

**science**

( T cos 60 = 110 T = 220 N

**algebra**

a) +(4x-3/6) = +(5-5x/10) b) -(4x-3/6) = +(5-5x/10) c) +(4x-3/6) = -(5-5x/10) d) -(4x-3/6) = -(5-5x/10) a and d are the same, scratch d b and c are the same, scratch c so a) +(4x-3/6) = +(5-5x/10) b) -(4x-3/6) = +(5-5x/10) so solve those last two :)

**Engl.**

Writeacher knows far more about this subject than I.

**Engl.**

"planned to seize" looks like a simple predicate to me. If it said: "planned to seize immediately" I would say "planned to seize" was the simple predicate and "planned to seize immediately" was the complete predicate

**Engl.**

agree

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