Thursday
April 24, 2014

Posts by Damon


Total # Posts: 16,214

math
if the pool is 76 feet long and each tile is 6 feet you need 13 tiles because 12 tiles only goes 72 feet However do you not need other rows of tile? This is a very strange question. Most tiles are about 6 inches, not six feet and they are square and you have to fit them in are...

Math
They would have to go 1296 miles in 7 days. 1296/7 miles/day 1296 / (7*24)miles/hour

Math
10/510 = .0196

science(check answers)
1.D yes 2.A yes 3.A yes 4.im not sure please help V = i R 12 = 4 R , R = 12/4 = 3 Ohms 5.false. I agree but am not sure what it means. One could always have a short circuit where current streams through doing nothing useful.

Physics
weight down = m g max friction force = mu m g centripetal force = m (lateral acceleration) mu m g = m a = m (.96 g) a = .96 g We call "lateral acceleration" centripetal acceleration :)

Physics
2.1) LOL - I would guess around mu = 0.96 2.2) 120,000 m/h * 1 h/3600 s = 33.33 m/s m v^2/R = .96 m g R = v^2/(.96 g) = 118 meters 2.3) mu = .8*.96 = .768 Normal F = m g cos 15 = .966 m g friction force = mu Normal = .768*.966mg =.742 mg component of weight down slope = m g si...

Physical Sciences
Type Mach 2 into Google and get back 681 m/s Ac = v^2/r = (681)^2/5800 = 80 m/s^2 80/9.81 = 8.15 g

Calculus
LOL, sketch a graph !

Physics
You are welcome :)

Physics
ke of ball at bottom = (1/2) m (2.44)^2 = 2.98 m Pe at top = m g h = m (9.81)(h) so 9.81 h m = 2.98 m h = .303 meters h = 1.47 (1 - cos theta) .303/1.47 = 1 - cos T .206 = 1 - cos T -cos T = -.794 T = 37.4 degrees

physics
(1/2)(4.008) V^2 = (1/2)(2500)(.037)^2 V = .924 m/s .008 Vb = (4.008)(.924 ) Vb = 463 m/s

physics
use conservation of momentum to get the velocity of the total mass (4.008 kg) just after collision in terms of bullet velocity Vb. Call that V. (1/2) m V^2 = (1/2) k x^2 that gives you V go back and get Vb

Patterns and rules unit test 7th grade
geometric sequeence a = -2 r = 6 An = a r^(n-1) A5 = -2 (6)^4 = - 2592 A6 = 6(-2592) = - 15552 A7 = 6 A6 = -93312

Physics
weight in air = 6400 * 9.81 volume of water displaced = 1 m^3 weight of water displaced = 1000 *9.81 *1 = 9810 N = force up from water tension = (6400 - 1000)(9.81) = 52,974 N

Physics
(1/2) m v^2 = .5 * .559 * 2.7^2

statistics
first one 12/45 second on 11/44 12/45 * 11/44

physics
a) v^2/R b) m v^2/R

physics
2000 u = 10 (200 cos 60 ) u = cos 60

physics
1500 * 20 = (1500+m)10 m = 1500

physics
Because the air we live in also has pressure no pressure change in a horizontal hose with no flow through it.

physics
rho g h = 1000 (9.81)(30) = 2.94*10^5 add 1 atm = 1*10^5 and get total of 3.9 * 10^5

CALC 2
try similar for the rest

CALC 2
1 at start a eats 2/3 ** 1/9 *** 1/54 b eats 1/6 ** 1/36 ** 1/108 first line is geometric series 2/3 + 2/3(1/6) + (2/3)(1/6)^2 ... An = 2/3 +(1/6)^n-1 sum of that series = a/(1-r) = (2/3)/(1-1/6) = 2/3 /5/6 = 4/5

Physics
You understand that he used quite different numbers in his example, D = 2.71 diameter 24 liters instead of 25 1.1 instead of 1.4 min

Physics
I found it all right. He has a pretty convoluted way of explaining it but it is the same thing. I have no idea why he converted to cm^3 rather than to meters^3 from Liters 1000 Liters = 1 m^3 1 Liter = 1000 cm^3 1 m^3 = 1,000,000 cm^3 but it is standard to work in meters, kg a...

Statistic
You are welcome :)

Statistic
p(good) = .7 , p(fail) = .3 n = 10 crunch it out with your binomial distribution P(2) for example = C(10,2)*.7^2*.3^8 = 10!/[8!*2!] * .49 * 6.56*10^-5 = 45 * .49 * 6.56*10^-5 = .001447

physics
work done = change in Ke = (1/2) m v^2 = 500*900 Joules power = work/time = 500 * 900 / 5 = 90,000 Watts

math
2 * 3 = 3 * 2 ????? Commutative

Calculus Help Please
f(x) = f(a) + (x-a) f'(a) f(x) = x^4 df/dx = 4x^3 let a = 2 then f(a) = 2^4 = 16 f'(a) = 4*8 = 32 f(x) = 16 + (x-a)(32) x-a = - .001 so f(1.999) = 16 -.001(32) = 16 - .032 f(1.999) = 15.968 with calculator it is 15.968 also

Math (check answer)
if you mean absolute value of 7 yes it is 7

Calculus Help Please!!!
at x = 3 y = 3*3 - 9 = 0 at x = 2.4 y = 3(2.4) - 2.4^2 = 1.44 delta y = 1.44 -0 = 1.44 dy/dx = 3 - 2 x at x = 3 dy/dx = 3 - 6 = -3 if dx = -.6 dy = -3 (-.6) = 1.8

Algebra
.163 x = 47600 x = 47600/.163

Math
You are welcome :)

Math C redone
should subtract 30 (14*2+2), not 44 c) draw a Venn diagram Only in A1 = 103 - 30 = 73 Only in A2 = 992- 30= 962 Only in A3 = 10011 - 30 = 9981 shared = 3*14 + 2 = 44 sum = 11060

Math
a) just add them 11106 b) They are all in A3 so 10011 c) draw a Venn diagram Only in A1 = 103 - 44 = 59 Only in A2 = 992- 44= 948 Only in A3 = 10011 - 44 = 9967 shared = 3*14 + 2 = 44 sum = 11018

Math
do you mean y = 18/(x^2-9) ???? if so dy/dx = -18 (2x)/(x^2-9)^2 0 at x = 0 In that interval the bigger |x|. the more negative the function so it is max when x = 0 18/-9 = -2 so C

math
You are welcome, good luck.

math
25 * .65 = 16.25 25 * 0.65 * 0.2 = 3.25 but I do not believe that 0.2. I think you have the loss 80% when it should be like 20%

math
the cooking loss is 80% ??? that does not sound right but if you are serious then 25 * (1-.35) (.2)= 25*.65*.2 = 3.25 pounds

Algebra
x^2 + (2x+20)^2 = (2x+22)^2 x^2+ 4 x^2 + 80 x + 400 = 4 x^2+88x + 484 x^2 - 8 x - 84 = 0 (x-14)(x+6) = 0 x = 14 2x+20 = 48 2x+22 = 50

physic
Plus charges flow to one side, minus charges to the other.

Calculus Help Please!!!
Oh, I see f(x) = ln (1+x) df/dx = 1/(1+x) d^2f/dx^2 = -1/(1+x)^2 f(x) = f(0) + [1/(1+0)] x - x^2/2! ... f(x) = 0 + x - x^2/2 + ..... well at a first cut when is x^2/2 =.1 x? x/2 = .1 x = .2

Incomplete!
Linear approximation to what function? Did you try to copy and paste? If so, that does not work here.

Physic
zero The plus charges on one side exactly balance the - charges on the other side. If you for example had more plus charges on one plate then they would attract negative charges to the opposite plate and would cause a flow across. Moreover the entire capacitor would then have ...

Science
I do not understand what the second question means? Balance the equations or what?

Science
Al is +3 here 2 Al + 2CuCl2 --> 2AlCl3 + 3Cu

Math
look for where second derivative is positive. ( x <0.75) https://www.wolframalpha.com/input/?i=second+derivative+of+-1%2F%28x-.75%29

Physical Science 9
Incomplete combustion ---> carbon particles and CO instead of CO2 That is not a good question by the way. You should know that for sure. The other things happen in: plants stomachs compost heaps and coffins not power plants

Physics 112
a) as t--> oo inductor is a short circuit, no reactance so V = i at big t * R V = (8.4)(.26) = 2.14 Volts b) at t = 0, i = 0, so all voltage across L 2.14 = L di/dt let i = 8.4 [ 1 - e^-t/tau ] given tau = .1 s i = 8.4 [ 1 - e^-10 t ] di/dt = 8.4 (10 e^-10 t) di/dt = 84 at ...

Math
1cm /50 in = 4 cm/x in x = 200 in

Math
It is not a proportion. It is a fraction. divide 144 by 1200 get .12 to convert a fraction to a percent, multiply by 100 100 * .12 = 12 %

Math
12/8 = 3/2 = boys/girls boys/total = 3/5 girls/total = 2/5 so that boys/girls = 3/2 so girls /total = 2/5 = girls/400 girls = 800/5 = 160

Physics
You are welcome :) Good luck. Come back and tell me when you find out.

Physics
I know the flow rate is the speed times the area. That is my field :)

Physics
I can not find an error. I hope one of the other math/physics teachers finds something.

Physics
call 41.18 41.2 maybe, sometimes they fuss about their round off rules.

Physics
Well, it is their word against mine I guess, but check my arithmetic and units carefully Physics - Damon, Sunday, March 30, 2014 at 7:21pm 25 L = 25 * 10^-3 m^3 2.77 cm = .0277 m 1.4 min = 84 seconds flow rate * time = amount pi r^2 v * 84 = .025 m^3 pi (.0139)^2 v = .025 v = ...

Steve, Reiny ??
I did this twice and do not see errors. Did I make some stupid mistake?

Physics
Well, figure out what I did wrong. (I think nothing)

This is getting tiresome
I answered this. Also the other one about circumferences several times.

Math
1/2 if a length dimension on the big one is twice the same length dimension on the little one then lengths on the small one are 1/2 those on the big one.

Math
4 * 50

Math
4 n - 6 = 2 n + 4 2 n = 10 n =5

math
22.5 quarts = .75 (total) total = 22.5/.75 we have .25 * total so we have .25 * 22.5/.75 =22.5/3 = 7.5

Physics
25 L = 25 * 10^-3 m^3 2.77 cm = .0277 m 1.4 min = 84 seconds flow rate * time = amount pi r^2 v * 84 = .025 m^3 pi (.0139)^2 v = .025 v = 41.18 m/s if 1/3 diameter then 1/9 of area so speed is nine times original 371 m/s

Physic
http://www.jiskha.com/display.cgi?id=1396215852

Physic
I did my best earlier.

Calculus Help Please!!!
LOL - Guess which of us is the mathematician and which is the Engineer :)

Calculus Help Please!!!
Q = incoming flow rate = .1 m^3/min dh/ dt = Q A where A = surface area = length * width at 20 cm depth which depth is (1/2) height width = 30 + 1/2(70-30) = 30+20 = 50 cm = .5 m wide water surface so A = 5 * .50 =2.5 m^3 so finally dh/dt = .1 * 2.5 = .25 m/min = 25 cm/min

Physics
vertical ? I thought table was level. I will assume you mean from the y axis. final momentum y component = m (5) cos 28 + m (4) cos 32 = 7.81 m final momentum x component (I will assume one + and the other -) = m (5) sin 28 - m(4) sin 32 = 2.18 m Now I will have to assume some...

Physics
inelastic, energy was radiated in sound waves

Physics
If Vector A + Vector B = Vector C then orthogonal components of the vectors also add. If V = A + B then Vx = Ax + Bx and Vy = Ay + By and Vz = Az + Bz and as many more dimensions as our tensor occupies ") (b) NO !!!!! It is only conserved in an elastic collision Energy is...

algreba
In both cases just add the two equations

My typo
" Libel is viewed differently in United Staes and Japanese law and is far more difficult to establish in a United States court. "

Proofreading..Jrn Law
Should it not say in an introductory sentence that you are talking about libel? Such as: " Libel is viewed differently in United Staes and Japanese law and is far more difficult to establish in a Japanese court. " win THE case or HIS OR HER case (singular or say &quo...

physic
Use the same argument but same voltage on each

physic
In series the charge has to be the same on both, call it Q by definition each capacitance C= Q/V so Veach = Q/C now in series the voltages on each capacitor add so V total = 2 Q/C but by definition our equivalent capacitance = Q/Vtotal = C/2

whoops
Use Steve's answer

math
makes good 2 miles per day after 12 day/night cycles is at the 24 mile mark so he will just make it at dusk on the 25 th day

physics
BUT they want miles/ hr so 29.4 m/s * 1 mile/1609 m * 3600 s/h = 65.8 miles/hour

physics
the ground is 3 seconds down d = (1/2) (9.81) (3)^2 correct d = 44.1 METERS (THAT IS PART B) (that is 9.81 m/s^2 * 9 s^2 so just m or meters) NOW THE SPEED (Part A) v = g t v = 9.81 m/s^2 * 3 s = 29.4 m/s (THAT IS PART A)

physics
You are terrribly fouled up with units. Give me a minute

physics
WORK IN METRIC convert later if dealing with carpenters.

physics
come on now, use what we have done v = g t but to go from m/s to mi/hr use 3600 seconds / hour and 1609 meters/mile a floor is about 3 meters

Math
2 = 1.0275^n log 2 = n log 1.0275 n = 25.6 years

statistics
Binomial distribution find probability of zero boys P(0) answer is 1 - P(0) n = 6 p = .5 and 1-p = .5 P(0) = C(6,0) (.5)^0 (.5^6) coef for any n,0 = 1 so P(0) = .5^6 = .0156 1-P(0) = .984

Math 110 UOP
Multiply 28x72 using lattice method. been there done that, see below and please post once HUH, 5^2 = 4^2 +3^2 if that is what you mean

Math 110
278 = 2*139 139 is a prime number to that is the end ***** 2 ***** 8 **** 1->2 1/4 **** 5/6 ** 7 9->0 0/4 **** 1/6 ** 2 11->1 *** 6 so 2016

physics
What speed does the ball in the first question have in falling 3.5 s? ------------------- I told you in the first line, 34.3 m/s ------------------- in 4 sec d = .5 * 9.81 *16 = 78.5 meters so no

physics
v = g t = 9.81 * 3.5 = 34.3 m/s but what if it hit the ground? d = (1/2) g t^2 = 60 meters so it has not hit ground yet, whew

Physics
area = A = pi D^2/4 = pi (.0277^2)/4 = 6.03*10^-4 m^2 Q = volume/second 25 * 10^-3 m^3 / 84 s = .298 *10^-3 m^3/s A v = Q v = Q/A = .298*10^-3/6.03*10^-4 = .0494 *10^1 = .494 m/s

physics
a = change in velocity/change in time = 44/5 = 8.8 ft/s^2 a = same formula = (88-44)/4 = 11 ft/s^2 a = (66 -88)/3 = -7.33 ft/s^2 sum of a*t / total t (8.8*5 + 11*4 - 7.33*3)/12 = 5.5 m/s^2

physics
5/20=4 km/min = 4,000 m/min = 66.67 m/s? BECAUSE 5/20 = 1/4 not 4

physics
5000 meters in 20*60 = 1200 seconds Vi = 30,000 m / 3600 s = 83.3 m/s v = Vi + a t 0 = 83.3 + a (1200) a = - .0694 = - 6.94 * 10^-2 m/s^2 average velocity with constant acceleration = (first + last)/2 = 83.3/2 = 41.7 m/s

physics
750 m/ 20 s 1500 m / 45 s

college algebra
2 x 10to the what? and 3.5 times ten to the what ?

US government
Well, presidents seem to start wars without much voting in Congress these days :)

US government
Well, I guess our first choices are consistent :)

US government
the government the citizens among many other possible answers such as: money, health military, poor capital , labor federal government , states

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