Wednesday
April 23, 2014

Posts by Damon


Total # Posts: 16,213

Physics
Pe at top = m g h = 3.3 * 9.81 * 1.03 a) Pe at 1.03-.27 = 3.3 * 9.81 * 0.76 find difference that difference is Ke in Joules so difference = (1/2) m v^2

Physics
falls 3 meters (1/2) m v^2 = m g (3) v^2 = 2 mg(3) v = sqrt (2 m g(3) You should remember forever This: when something falls distance h from zero speed at top and no air drag v = sqrt (2 g h) mass does not matter for this

Physics
Ac = v^2/r = omega^2 r v = omega * r omega = 33.3 * 2 pi / 60 = 3.49 radians/second Ac = 3.49^2 (.15) = 1.82 m/s^2 2. F = m a = .0073 * 1.82 = .0133 Newtons

algebra
use 4 for x f(4) = 4 * 4 + 7 = 16 + 7

Physics 141
speed of rock = 15.5 , mass = .32 speed of wagon = v , mass = 92.7 initial momentum = 93 * .52 = 48.4 final momentum = initial momentum so 48.4 = .32*15.5 + 92.7*v solve for v if backward 48.4 = -.32*15.5 + 92.7*v

Calculus Check my answer
integral (x^2/2 + x + 5)dx x^3 /6 + x^2/2 + 5 x at 4 minus at -4 64/6 + 8 + 20 - ( -64/6 + 8 -20 ) 64/3 + 20 + 40 64/3 + 180/3 = 244/3 = 81 1/3

Chemistry
HCl + NaOH --- > H2O + NaCl balanced as is One mole of NaOH for every one mole of HCl because the equation balances with one of each .68 * .29 = .1972 moles of HCl so we need .1972 moles of NaOH

algebra
y = k x -252 = k (84) k = -252/84 = -3 y = -3 (74) y = - 222

science(check answers)
2. I think B

Physics 141
south momentum = 75 * 7.35 = 551 east momentum = 45 * 2.85 = 128 new mass = 45 + 75 = 120 new momentum = old momentum (Newton #1 law) south speed = 551/120 = 4.59 east speed = 128/120 = 1.07 theta = tan^-1 (4.59/1.07) = 76.9 degrees Vf = sqrt(4.59^2+1.07^2) = 4.71 m/s

Math
12/4 = 3

Math
u - 10 = -12 add 10 to both sides u = +10 -12 u = -2

Math
2009 20,480/.98^4 2010 2011 2012 20,480/.98 2013 20,480 20,480/.98^4 = 22,204 domain is 2009 to 2013 as far as we know and the range is 20,480 to 22,204

math
A = 3 B C = 2.2 B C/A= 2.2/3 = .733 C is not more potent than A. It is 73.3 percent as potent as A

Physics!
2*2.4 /1 watts = 4.8 watts

math
8/10 = .8 = likely

Physics
the same as the work done lifting it m g h = 600 * 1.6 Joules

Physics
600 * 9.81 * 1.6 Joules

math
4/56 is unlikely

Finance
.11*68 = 7.48 7.48 - 3.85 = 3.63 expected increase in price 3.63 = x (68) x = .0533 or 5.3%

physics
Fx = 35 cos 25 friction work = -35 cos 25 (20) gravity does none, not in the direction of motion same as friction work but positive sign Fx = friction work /20 and F = Fx/cos 25 total work is friction work since no vertical motion

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

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