Wednesday

July 23, 2014

July 23, 2014

Total # Posts: 17,491

**math**

A cube only has 6 sides but anyway on your octahedron 2,4,6,8 are even 1,3,5,7 are odd so probability of even is .5, probability of odd is .5 in other words, likely as not

**math**

C = 2 pi R

**Math**

Yes

**physics**

weight = 1550 * 9.81 so force up = 1550*9.81 + 125 work = force up * 40 meters

**Algebra 1 (Step-by-Step)**

first I have to take a -1 out so it is easier -1(4 x^2 + 8 x - 5) one way to get 8 is with 2 and 10 -1 (2 x + 5)(2 x - 1)

**Geometry**

Huh? in a rectangle the diagonals are equal. 18 x - 28 = x + 380 17 x = 352 x = 20.7 etc

**Calculus**

I think you did it correctly. Of course the domain is limited because the answer is imaginary if x <3

**English**

4. added Well, it is vocabulary :)

**math**

It is difficult to make a seven apple pie with six apples, but so be it, go ahead, make the pie with less apple.

**Physics**

F = -kx = m a assume simple harmonic motion y = A sin (2 pi f t) then a = acceleration = - (2 pi f)^2 y ans -k y = - m (2 pi f)^2 y or 2 pi f = sqrt (k/m) period = 1/f = (1/2pi) sqrt(m/k) double m 2 pi f' = sqrt(k/2m) = old f/sqrt 2 3. well same deal but times sqrt 2 now

**Physics**

100 = k x 120 = k (x+.04) = k x + .04 k -----------------------------subtract -20 = kx - kx - .04 k 4 k = 2000 k = 500 N/m

**Algebra**

No (v^2 -9) = (v+3)(v-3) BUT (v+3)(v+3) = v^2 + 6 v + 9

**science**

loss of nutrients, must add fertilizer or rotate crops preferably with something like beans that fixes nitrogen from the air into the soil for decomposition if you have to pick one pick b

**science**

meanders are formed by the flow scouring one side of the stream and depositing on the other so I would say it is evidence of eroriding and depositing glacial till is junk deposited by glaciers 3 = a) but you knew that

**Physics**

because it has a battery which is charged by sunlight.

**Physics**

If the resistors are all in SERIES then the total resistance is the sum: 7 + 9 + 2 = 18 ohms i = V/R = 9/18 = 0.5 amperes

**physics**

almost 8 m/s (in my head)

**physics**

dropped 3 meters if no friction (1/2) m v^2 = m g h v = sqrt (2 g h)

**Physics**

weight = m g = 5.19 (9.81) normal force = 5.19(9.81) - 3.23 sin 20 pull force = 3.23 cos 20 work done per second = power = 3.23 cos 20 (3.38) Watts. Without time can not get energy. power wasted to heat = all of it above 3.23 cos 20 = mu (normal force above)

**Physics**

distance block moves down = ho + .198 loss of potential energy by block = .540 ( 9.81 ) (ho+.198) gain of potential energy by spring = (1/2)(320)(.198). This is energy gained by spring and lost by block. so .540(9.81)(ho+.198) = (1/2)(320)(.198) solve for ho then do it for 3 ho

**science**

v = Vi + a t v = 2 + 5*4 = 22 m/s

**Math**

2 L + 2 w = 54 so w = 27 - L also w = L/2 so L/2 = 27 - L 3 L/2 = 27 L = 18

**math**

x+2 = -2x + 20 3 x = 18 x = 6 so side = 8 14 - 8 = 8 so 14-x works and 2x + 4 is not 8

**Physics**

mgh = 10 * 9.81 * 1 + 20 * 9.81 * (1/2)

**Physics**

typo = Fx(R1y-R2y)k + Fy (R2x-R1x)k By the way the vector product F X (R2-R1) is a moment called a "couple".

**Physics**

I will do it in two dimensions, similar in 3 moment = F1 X R1 + (-F1) X R2 = (R1y Fx - R1x Fy)k -(R2y Fx -R2x Fy)k = Fx(R1y-R2y)k +Fy (R2x-R1y)k so in k direction and depending only on how far apart the two forces are, not the origin of R1 and R2

**Mathematics**

18/2

**Please Help with Physics Problems???????**

Spring potential energy = (1/2) k x^2 total energy = (1/2) m v^2 + (1/2)k x^2 = 8.6 Joules Power = F v = k x v

**Physics please help?????**

2.9*-3.2 +5.7*4.6 = 16.4 W yes -1.7 * v = -6 v = 3.53 m/s

**physics**

h = Hi + Vi t - 4.9 t^2 0 = 8 + 3 t - 4.9 t^2 t = [ -3 +/- sqrt (9+157) ]/-6 t = [ - 3 + / - 12.9 ] / -6 = -.5 +/- 2.15 = 1.65 seconds

**Maths**

12 + n = .5(42+n) 12 + n = 21 + .5 n .5 n = 9 n = 18

**Physics**

1200 * 9.81 * 30

**Physics**

a = F/m

**Physics**

v = Vi - 9.81 t v = 0 at top 0 = 10 - 9.81 t t = 1.02 seconds upward h = Hi + Vi t - 4.9 t^2 h = 0 + 10(1.02) - 4.9(1.02)^2 h = 10.2 - 5.1 = 5.1 meters note - this has nothing to do with the mass of the ball.

**physics30**

potential energy = m g h = 56*9.81 * 3.5 kinetic energy = (1/2) m v^2 = 28*16 sum to get total energy at top kinetic energy at bottom = (1/2)m v^2 = total energy at top - 900

**physics30**

not moving so zero

**physics**

decrease in potential energy = gain in kinetic energy so v^2 is the same for both

**1 question!**

Only one of those is problems with muscles and joints.

**Physics**

work = integral f dx = change in kinetic energy if this is the only force v =dx/dt = 4.1 -7.2 t + 13.5 t^2 at t = 0, v = 0 at t = 8.6 v = 4.1 - 7.2(8.6) + 13.5 (8.6)^2 = 941 m/s^2 Ke = .5 m v^2 = .5(1.1)(942)^2 = 486,642 Joules

**MATH**

twice the size would be 100% increase three times the size would be 200% increase

**chemistry**

I think maybe you better look up the solubility which is normally in grams or mols per liter but 36 grams in 100 grams is much higher than believable by any stretch of the imagination. A liter of fresh water is about a 1000 grams.

**Algebra ll**

You are welcome :)

**Algebra ll**

year 0 --> 1 year 1 --->3 year 2 ---> 9 year 3 ---> 27 . . .

**Algebra ll**

Oh my pet mouse has three babies every year each of those has three every year each of those has three every year how many are born in year t ?

**Algebra ll**

A lazy row in my dory is at 3 nautical miles/hour. so in t hours I go 3 t nautical miles so my distance y is modeled by the equation y = 3 t

**typo, gravity wrong**

a) Hey, you know what h is when t = zero! b ) h = -4(1) + 16(1) + 9 = 21 c) If you do not know any calculus, which I assume you do not or you would not be asking, then you must complete the square to find the vertex of the parabola t^2 - 4 t = -h/4 + 9/4 t^2 - 4 t + 4 = -h/4 +...

**Math**

5 y = -3x + 2 y = (-3/5) x + something slope of line = -3/5 so our line has form y = (-3/5) x + b 3 = (-3/5)2 + b 15/5 = -6/5 + b b = 21/5 so y = (-3/5) x + 21/5 5 y = -3 x + 21 3 x + 5 y = 21

**Math**

ok so w = x = 10 A = 50 w -2 w^2 = 50 x - 2 x^2 = 50(10) - 2(100) = 500 - 200 = 300 m^2

**Math**

well, I do not know which is x and which is y so I will call them w and L 50 = 2 w + L so L = 50 - 2 w or w = (50-L)/2 A = w L = [(50-L)/2]L = 25 L - L^2/2 or A = (50 - 2w)w = 50 w - 2 w^2 since I do not know which is x, I can not help with c

**Physics**

first how long before it hits ground? 83 = 4.9 t^2 t = 4.12 s so it fell for 4.12 - 1.60 = 2.52 seconds so how far did it fall in 2.52 seconds? d = 4.9*(2.52)^2 = 31 meters so it is 83 - 31 = 52 meters up

**Business Calc**

perhaps by taking a log to some base of both sides :)

**Math**

x = k y^3 32 = k (8) k = 4 x = 4 y^3 x = 4 (-27) x = - 108

**physics**

A ) m g h = 2 * 10 * 17 = 340 Joules B ) zero C ) at top Ke = 17 and Pe = 340 so at bottom where Pe = 0 then Ke = 357 I do not understand why you are asking because the problem leads you step by step to the solution.

**Physics**

Unfortunately, no figure here

**Algebra**

" ....The next day she did the same number of exercises ...... " This clues me in to set a total number of exercises, which I call "total" that is the same both days. if she does 3 execises per hour I call that rate p per hour then p exercises/hour * 3 hour...

**Algebra**

total = p * 3 total = q * 2 where q is new improved rate so q * 2 = 3 * p q = (3/2) p = 1.5 p

**Physics**

Not much of a cannon :) time to fall to ten meters = time to rise ten meters 10 = (1/2) g t^2 = 4.9 t^2 t = 1.43 seconds up or down v = Vi - g t 0 = Vi -9.81 (1.43) Vi = 14 m/s muzzle velocity now at 33 deg u = 14 cos 33 = 11.8 m/s forever Vi = 14 sin 33 = 7.62 initial speed u...

**PHYSICS**

F2^2 + 12^2 = F1^2 right triangle, F2 smaller F1 = (18 - F2) F2^2 + 144 = 324 -36 F2 + F2^2 36 F2 = 180 F2 = 5 then F1 = 18-5 = 13

**Physics**

There is no net force on the object if it is moving at constant speed Therefore if it is moving in the direction of F2 then the sum of the other two forces must be equal and opposite to F2

**Physics**

|F1 + F3| = |F2| since the resultant force on the object is zero (constant speed, no acceleration, no force)

**business math**

day shift 40 * 8.25 overtime 58-6 -40 = 12 *1.5*8.25 midnight shift 6* 2 * 8.25 so 8.25 (40 + 18 + 12) = 67*8.25 = 552.75 pass higher minimum wage !!!!

**science**

You are welcome, good luck !

**science**

You are implying that the number of sprouts is proportional to the concentration sprouts = k * c in which case k would be undefined for zero c However I doubt if that sort of relationship exists. the number of sprouts probably does increase with c but levels off at some value ...

**Algebra**

Yes, I suspect d is correct.

**Algebra**

height and hair color ? That is interesting :)

**Physics-motion**

distance accelerating = (1/2)at^2 same distance de-accelerating so L = a t^2 t = (L/a)^(1/2) I do not agree with the 4

**G.N.M.P.S**

mass of water displaced = 1000 - 75 = 925 g so if the water density is 1 g/ cm^3 its volume is 925 cm^3 the mass of oil displaced is rho*925 g so rho*925 = 1000 - 70 = 930 g so rho = 1.0054 g/cm^3 Strange oil. Most oil floats on water.

**History**

People got dirty, either in the coal mines or in the factories. People moved from the country to the cities to man factories. Countryside went to estates ruled by country squires who gained power through a policy called "enclosures" which disenfranchised poor country...

**physics**

120 mi/h (1609 m/mi)(1 h/3600s) = 53.6 m/s F = change in momentum/time = 60 (53.6)/56 = 57.5 Newtons

**Math~**

13 - 3 = 10 for (n-1) people 10 - 2 = 8 for (n-2) people if one has 2 so if (n -2) people eat 1 each, then n-2 = 8 and there are max of 10 people but (n-2) people might eat 2 each so in that case there would only be 4 of them and n - 2 = 4 so n = 6 so 6 min and 8 max but 7 is...

**ECON**

This is called a "sinking fund" S = N [ (1+r)^n -1 ]/r N = amount deposited each period r = decimal interest rate per period n = number of periods, compounded here N = 250 r = .09 n = 20 so S = 250 [ (1.09)^20 -1 ] / .09 S = $ 38,370.09

**typo**

1:30pm-2:5pm do you mean to 2:50 pm ??? as I told you and Ms Sue told you that is 60 + 20 = 80 minutes

**calculus**

3 * 2 pi = 6 pi radians/minute pi/6 = 30 degrees by the way I call your angle theta A dA/dt = 6 pi rad/min tan A = x/7 x = 7 tan A dx/ dt = 7 d/dt(tan A ) = (7/cos^2A) dA/dt cos^2 (30) = .75 so dx/dt = (7 miles/.75)(6 pi rad/min) dx/dt = 176 miles/min * 60 = 1055 miles/hr so d...

**Algebra**

Oh, yes, I did not notice your answer, which is correct.

**Algebra**

This is a pretty fundamental question. What do you think the answer is?

**Math Time**

You better get an analog clock so you can run your finger over the face. I knew we were all in trouble when the digital time started. 1:30 to 2:30 is an hour, 60 minutes this is 15 minutes LESS !!!

**calculus**

by the way, d/dt (tan A) = sec^2 A * dA/dt = (1/cos A)^2 * dA/dt

**calculus**

Hey, I just did one very much like this. Your turn.

**Math Time**

1:30 - 2:30 = 60 min 2:30 - 2:50 = 20 min 60 + 20 = 80

**Calculus**

y = 1 e^(rx) y' = r e^(rx) y" = r^2 e^(rx) r^2 - 4 r + 1 = 0 r = [4 +/- sqrt (16 -4) ] /2 r = [ 4 +/- 2 sqrt 3 ]2 r = 2 +/- sqrt 3

**flagpole math**

How far away is he? Otherwise I can only give you the function. man is p from pole (we need this) shadow tip is s from pole we want ds/dt s/5 = (s-p)/1.5 1.5 s = 5 s - 5 p 3.5 s = 5 p s = 1.43 p ds/dt = 1.43 dp/dt but dp/dt = 1.8 so ds/dt = 2.57 m/s

**Algebra word problem**

yard 48 x^2 + 36 x + 6 patio 3 x^2 + 16 x + 5 subtract 45 x^2 + 20 x + 1

**calculus**

Oh, it is pointed at the bottom? area = pi r^2 radius = (1/3) h for 1 at the top and 0 at the bottom so surface area A = pi (1/9)h^2 for h = 2.6, A = 2.36 meters^2 d V = A dh dV/dt = A dh/dt or dh/dt = (1/A)dV/dt dV/dt given as 1.4 m^3/min so dh/dt = 1.4/2.36 = .593 m/min

**MATH**

Does the problem ask for the vertex? the zeros? what?

**what about it ?**

That is a parabola, do you want to graph it or what?

**math**

2 x^2 + 2 = 2 (x^2+1) so what? There is no problem here, you do not say what you want.

**Physics**

Floor pushes up total weight = (39.7 + 65.3)(9.81) crate pushes up on person = (65.3)(9.81)

**Algebra**

well the way I see it it is (6 x^3 - 18 x ) + (5 x^2 - 15) which is 6 x ( x^2 - 3) + 5 (x^2 - 3) get it ?

**AMERICAN HISTORY**

Dutch in New York, Germans in Pennsylvania, Swedish in Delaware, Catholics in Maryland, which would you pick.

**math 2**

How many cereal boxes does he want to put in the big box?

**english**

I think it is more likely the birds and bees than elves though.

**english**

1. agree 2. I have a hunch it is d 3. yeah, ok 4. I think a

**physics**

weight = m g friction force = mu m g so static mus 75 = mus (20)(9.81) and kinetic muk 60 = muk (20)(9.81)

**Physics**

well, If he jumped up, all bets are off. If he just fell off then: v = sqrt (2 g h) because m g h = (1/2) m v^2 conservation of energy g h = (1/2) v^2 so v = sqrt (2*9.81*15) = 17.2 meters/second

**Algebra**

6x*2x - 6x*3 - 5*2x + -5*-3 12 x^2 - 18x - 10 x + 15 12 x^2 - 28 x + 15

**math**

that is 39 ------------- 2 x + 1 - 10 x which is 39 ---------------- 1 - 8x

**math**

so it is 39 ------------------------ (2x+1) -2x(5) ?

**math**

I do not understand it what is the numerator and what is the denominator?

**math**

18 is divisible by 3 6 9 18 and 2 1 row of 18 6 rows of 3 9 rows of 2 2 rows of 9 etc

**English**

2 - I think d I agree with the others

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