Thursday
December 18, 2014

Posts by Damon


Total # Posts: 19,955

Math
yes
October 10, 2014

Physics
we do not have your figure.
October 10, 2014

calculus
series for f(x when a = 0: tan x = tan 0 + sec^2 0 (x) + .... = 0 + 1 x ..... when does x = tan x +/- .1 make a table of x in radians vs tan x
October 10, 2014

Algebra- please help answer
5 815/1000 6 21/1000 --------------- 11 836/1000 = 11 418/500 = 11 209/250 11.836
October 9, 2014

Algebra
.75 + .125 + .09 = .965 1.2 - .965 = .235
October 9, 2014

Algebra whoops !
11 209/250
October 9, 2014

Algebra
11 836/1000 = 11 209/1000
October 9, 2014

physics
2*10/d^2 = 4*10/(12-d)^2
October 9, 2014

physics
component of weight down ramp = 600 sin 30 = 300 pounds
October 8, 2014

No idea
I have no idea what your jockey experiment is.
October 8, 2014

physics
http://science.howstuffworks.com/transport/engines-equipment/pulley.htm
October 8, 2014

Physics
Pulling with component up on block reducing the normal force between block and floor and thus reducing friction force which is maximum of coefficient of friction times normal force.
October 8, 2014

math
I do not understand. There are only four aces in the pack. If order is not important, then there is only one way.
October 8, 2014

math
combination of 4 jacks 3 at a time C(4,3) = 4! /[ 3! (4-3)! ] = 4 combination of 4 twos 2 at a time c(4,2) = 4! /[2!(4-2)!] = 3 so 4*3 = 12
October 8, 2014

Math! Please check!
You are welcome, good luck.
October 7, 2014

Math! Please check!
Got it ?
October 7, 2014

Math! Please check!
Yes and yes To remember forever: 1. Hypothesis: If cow , then mammal 2. converse: If mammal,then cow (maybe) 3. inverse: If not cow, then not mammal (maybe) 4. contrapositive: If not mammal, then not cow (true) Make Venn diagrams for the situation :)
October 7, 2014

Math
http://davidmlane.com/hyperstat/z_table.html
October 7, 2014

math
(5/4) *120 = 5 * 30 = 150 pennies which is $1.50
October 7, 2014

math(fractions)
but 90/20 is 9/2 which is 4 1/2 which is 4.5
October 7, 2014

Algebra
It is going to be ten times as big.
October 7, 2014

Algebra
how many 125s in 8450 ? 8450 ----- = 67.6 so 67 full rows 125
October 7, 2014

Algebra
well, we sure seem to be into division :) 384,400 -------- = 110.587 so 111 3476 because .587 is more than half way from 110 to 111
October 7, 2014

Math! Please check!
I agree with all of your choices.
October 7, 2014

physics
v = Vi + a t 152 = 0 + 1.35 * 10^4 t but 1.35 * 10^4 = 135 * 10^2 t = (152/135) * 10^-2 = 1.13 * 10^-2 = .0113 seconds
October 7, 2014

What pulley system
I have no idea what your block and tackle looks like so can not calculate the mechanical advantage. Divide 1000 by the number of parts of the line pulling up on the piano.
October 7, 2014

PHY1015S
Two of them :)
October 7, 2014

Math
if you do not know calculus area of surface = pi d^2/4 area of surface * change in height/min = volume/minute pi d^2/4 * .24 m/min = pump rate - leak rate
October 5, 2014

Math
0.16 c = 4 so c = 4/0.16 = 25 then yes, subtract 4 and get 21
October 5, 2014

Confusing increase in percent
That is always confusing and the thing to remember is that doubling is 100% increase.
October 5, 2014

Math
If the result is 400% of the original 100%, then the increase is 300% +100% = doubled +200% = tripled +300% = quadrupled
October 5, 2014

Physics gr. 12
You went about this correctly. I did not check the arithmetic.
October 5, 2014

Math
+++++++ 2 x___+ 1_______ 5x-6 / 10 x^2 - 7 x - 6 ++++++ 10 x^2 -12 x +++++++++++++++ 5 x - 6 +++++++++++++++ 5 x - 6 Remainder = 0
October 5, 2014

math
at t = 0 xA = -20 , dxA/dt = -24 yA = 0, dyA/dt = 0 xB = 0, dxB/dt=0 yB = 0 , dyB/dt = 25 Dx = differnce in x location = 20 + 24 t Dy = difference in y location = 25 t distance = (Dx^2+Dy^2)^.5 distance = [ 400+480t+576t^2+ 625t^2 ]^.5 = [1201 t^2 + 480 t + 400 ]^.5 d distance...
October 5, 2014

solve long divison polynomials
http://www.jiskha.com/display.cgi?id=1412542641
October 5, 2014

probability;math
By the way, they were trying to trick you. If the Jack were NOT replaced, there would only be 51 cards when you went to pick the 8. Then it WOULD HAVE BEEN 4/52 * 4/51
October 5, 2014

probability;math
as long as it is replaced, the events are independent 4/52 * 4/52
October 5, 2014

Physics
v = Vi + a t Vend = 24 + 35 (1.9) angle at 1.9 s = 1.9(Vi+Vend)/2 total angle = 436 + angle at 1.9 s time at Vend = 1.9 + 436/Vend
October 5, 2014

Math Growth Rate w/ inflation
1.5 = (1+r)^3 log 1.5 = 3 log (1+r) 1 + r = 1.1447 r = .145 so 14.5 percent 1.08 = 1.1447^n find n continuous 1.5 = e^3k ln .5 = 3 k
October 3, 2014

Physics
4.92/360 = 500/c c = 36,585 km approximate check a degree on a great circle (around any circumference) of earth is 60 nautical miles :) (1.852 kilometers / naut mile) 360 * 1.852 * 60 = 40,000 close enough
October 3, 2014

Math
3.647 - 3.003 = 0.644 = 0.6
October 3, 2014

Math (Confused, no idea where to begin)
if t = 5 2 e^-(.16*5)=2 e^-.8 = 2/e^.8 = .899 = .90 volts 1 = 2 e^-(.16t) ln .5 = -.16 t t = 4.33 seconds at 0 sec V = 2 at 5 seconds V = .90 V = Vi (r)^t .9 = 2 r^5 .45 = r^5 log .45 = 5 log r r = .852 so every second multiply by .85 so decreases by 15% every second
October 3, 2014

error
parallel to y = 5 x - 6 so slope = 5 so dp/dx = 5 at x = 4 dp/dx = slope(x) = (x-1)(1) + (x+k) (1) = x - 1 + x + k = 2x+k-1 at x = 4, dp/dx = 7+k so 7+k = 5 k =-2
October 3, 2014

CALC AB
parallel to y = 5 x - 6 so slope = 5 so dp/dx = 5 at x = 4 dp/dx = slope(x) = (x-1)(1) + (x+k) (1) = x - 1 + 1 + k = x+k at x = 4, dp/dx = 4+k so 4+k = 5 k = 1
October 3, 2014

Math
cos theta = .2
October 3, 2014

Calculous Pre
I guess by growth rate you mean with yearly compounding and continuous means e^kt if yearly for three years 15 = 11 (1+r)^3 1.3636 = (1+r)^3 log 1.3636 = 3 log (1+r) 1+r = 1.1089 so r = .109 = 10.9 percent now if continuous 1.3636 = e^3k ln 1.3636 = 3 k k = .103 or 10.3 ...
October 3, 2014

Math Calculous Hey
Hey, I just did two of these, please use one name and do not ask me to do a whole bunch of virtually identical problems.
October 3, 2014

Pre-Calc
a b^t = 2 e^(8t) ln a + t ln b = ln 2 + 8 t a = 2 and ln b = 8 so b = e^8 = 2980 so I agree
October 3, 2014

physics
Fn = 62.6 Fw = 45.9 |F| = sqrt (62.6^2+45.9^2) = 77.6 angle north of west = tan^-1 (62.6/45.9) = 53.8 degrees so to cancel that 77.6 at 53.8 south of east
October 3, 2014

PHYSICS
work = force * distance in direction of force 2.5*10^-4 = .36 x x = 6.9*10^-4 meters
October 3, 2014

Physics
I will assume he just stops the descent of the ball change of ball velocity = 29 m/s a = change of velocity/time = 29/(16*10^-3) = 1.81 * 10^3 m/s^2
October 3, 2014

Physics
F = G Mm/r^2 F = m a = m v^2/r so G M m/r^2 = m v^2/r v^2 = G M/r G M same for both va^2 ra = vb^2 rb but va = 82 vb 6724 vb^2 ra = vb^2 rb so rb = 6724 ra circumference = 2 pi r period = circumference / v = 2 pi r/v period a = 2 pi ra/82 vb period b = 2 pi 6725 ra/vb 1/82 / ...
October 3, 2014

CALCULOUS
1.043^n = 2 n log 1.043 = log 2 n = log 2/log 1.043 = 16.5 years
October 3, 2014

Science
http://www.jiskha.com/display.cgi?id=1412288943
October 2, 2014

Very important
Go back and read my reply about the bottles moving at constant velocity !!!!
October 2, 2014

Science
a = 2 (1.5)/3.6^2
October 2, 2014

sign error
-h/h or -1
October 2, 2014

Math
f(2+h) = |2+h-5|-7 = |h-3| -7 as h---> 0 this is 3-h-7 = -h -4 f(2) = |-3| -7 = 3-7 = -4 so [ -h - 4 + 4 ] /h = h/h = 1
October 2, 2014

What collision, where?
I do not read minds.
October 2, 2014

Physics
I just showed you how to do the one with the train and the car.
October 2, 2014

Physics
car: v = 36 + 4 t x = 35 + 36 t + 2 t^2 train v = 22 x = 22 t the time t and the position x are the same at passing 22 t = 35 + 36 t + 2 t^2 solve quadratic for t go back and find v = 36+4t
October 2, 2014

physics
F sin 30 = 1.2 sin 30 = 1/2 F = 1.2/(1/2) = 2.4 N
October 2, 2014

Science
NO No NOOOO !!!!!! constant velocity is NO FORCE very, very important Force = mass * ACCELERATION not velocity but CHANGE in velocity/time
October 2, 2014

Science
F = m a = change in momentum/change in time (again) if there is no change in velocity there is no change in momentum and the net force on the bottle is zero so the forces are "balanced".
October 2, 2014

physics
|F| = sqrt (8.85^2 + 2.21^2) m = |F|/a = |F|/4.4
October 2, 2014

Science
F = m a =change of momentum/change in time so it accelerates, changes velocity
October 2, 2014

physics
a) m g h b) (1/2) m v^2 c) answer a - answer b = energy lost to friction energy lost to friction = work done by friction (friction force on tree *distance down) so friction force = energy lost/13 meters
October 2, 2014

physics
initial potential and total energy = E =m g h there is no friction in this problem so the total mechanical energy stays the same (1/2) m v^2 + m g h = E at every height h, you can calculate v
October 2, 2014

Social Studies
I believe that you are correct. I am sure that D is incorrect :)
October 2, 2014

Physics
10 min = 600 seconds 2,000 watts * 600 seconds = 1,200,000 Joules = 1.2*10^6 = 12 * 10^5
October 2, 2014

Math Help!!
In other words I think question 8 is missing the word "not".
October 2, 2014

Math Help!!
In number 8, B is the only one that is not a repeater https://www.google.com/search?q=repeating+decimal+definition&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=sb
October 2, 2014

Math Help!!
When in danger or in doubt, sketch the problem on a number line :)
October 2, 2014

Math Help!!
3. 7.2 x 12 x 0.23 = ? Round to the nearest hundredth. 19.872 since 2 is less than five, the nearest hundredth is 7 so 19.87 which is C as Brady said.
October 2, 2014

Geometry
(4/3)pi r^3 = 3,000 r^3 = 9000/(4 pi) r = [9000/(4 pi)]^(1/3) 4 pi r^2 = 4 pi [9000/(4 pi)]^(2/3)
October 2, 2014

Science--3 questions? :c
http://en.wikipedia.org/wiki/Nebular_hypothesis longitude altitude
October 2, 2014

Science
suspect you mean evolution on which case I would vote for a) with Darwin genetic adaptation http://grapes.msu.edu/integrated_pest_management/how_pesticide_resistance_develops
October 2, 2014

Int. science
I agree :)
October 2, 2014

Int. science
Oh, please guess !
October 2, 2014

statistics
I think you mean standard deviation of 9 http://davidmlane.com/hyperstat/z_table.html
October 2, 2014

Distributive Property Algebra
8(6 - 2) = 8(6) - 8(2) by distributive property of multipication = 48 - 16 = 32 --------------------------- You could also say 8*4 = 32 but that does NOT USE distributive property. ------------------------- 7 c + 7*4 by distributive property then = 7 c + 28
October 2, 2014

science
I am assuming that you are correct; the water evaporates
October 2, 2014

physics
That depends If you are in an car: If it is taking off from a stop light and accelerating forward then Thrust is greater than Drag If it is cruising along at constant velocity then Thrust forward equals drag back If you take your foot off the gas and coast then Thrust becomes ...
October 2, 2014

physics
drag is normally opposite to velocity.
October 2, 2014

Algebra
You are welcome.
October 2, 2014

Algebra
5m and 3 m are indeed like terms (combine like terms to make 8 m + 6 p + 4)
October 2, 2014

Math
(A) 2/5 (B) 2/5 = 24/60 (C) 2/5= what/35 multiply 2/5 by 7/7 and get 14/35 so 14
October 2, 2014

Intro to Physical Science
m g h = potential energy at top = 100 * 9.81 * 12 = 11,772 Joules loses 3550 Joules so (1/2) (100) v^2 = 11,772 - 3550 = 8222 Joules v = 12.8 m/s
October 2, 2014

Math
17 * 85/6
October 2, 2014

n2 maths
pi (25)^2/4 * 40 = n (4/3) pi (3)^3 6250 = 36 n
October 2, 2014

math n2
tan 58 = h/380
October 2, 2014

physics
d = .5 a t^2 a = 6/t .01 = .5 (6/t)t^2 = 3 t t = .00333 s F = change in momentum/change in time = .45 *6/.00333 = 810 Newtons
October 1, 2014

physics
10^3*10^8 = 10^11
October 1, 2014

Physics
h = (1/2) g t^2 in metric, g = 9.81 meters/s^2 in English g = 32 feet/second^2
October 1, 2014

calc / physics
yes yes
October 1, 2014

Algebra
- x^4 always - (-x)^4 always + x either -x either
October 1, 2014

Math
f(8+h) = sqrt (8+h) - 8 f(8) = sqrt(8) - 8 subtract sqrt (8+h) -sqrt (8) but d/dh (8+h)^.5 = .5 (8+h)^-.5 so sqrt (8+h) = sqrt 8 + .5 h/sqrt(8+h) subtract sqrt 8 .5 h/sqrt(8+h) divide by h .5/sqrt (8+h) let h -->0 .5/sqrt 8
October 1, 2014

math
x = [ -5 +/- sqrt(25 + 8) ]/4 = [ -5 +/- sqrt (33) ]/4
October 1, 2014

physics
a = change in velocity / change in time -.87 = change in velocity / 3.8 so change in velocity = -3.3 m/s
October 1, 2014

Chem 400
It is there 0.6548 g/mL *10^-3 mL/ uL =.6548 *10^-3 g/uL
October 1, 2014

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