Sunday
December 21, 2014

Posts by Damon


Total # Posts: 19,972

math error
99*50 = 4950
December 1, 2014

math
try 1 to 5 1 + 2 + 3 + 4 + 5 = 15 that is five numbers the middle one is 3 which is (1+5)/2 so try 1 to 99 that is 99 numbers the middle one is (1+99)/2 = 50 so try 99*50 =100*50 - 99 = 4901 ================================ try 1+3+5 = 9 which is 3 (1+5)/2 = 3*3 try 1+3+5+7 = ...
December 1, 2014

MATH
app makes x journeyman makes 3 x master makes 4.5 x 8.5 x = 5950 x = 700 etc
December 1, 2014

physics
no L the same, g different
December 1, 2014

physics
L/g important, not m
December 1, 2014

physics
k and m the same
December 1, 2014

Algebra 2
we have a circle with radius 2 sqrt5 and center at the origin and a parabola that looks like: 6 y = x^2-28 y = (x^2-28)/6 opens up (holds water) zeros at x = +/- sqrt 28 so vertex at x = 0 then y of vertex at -28/6 NOW SKETCH A GRAPH now do algebra x^2 + y^2 = 20 x^2 - 6 y = ...
December 1, 2014

Algebra 2
Very similar to the one I just did for you, another parabola intersecting a circle
December 1, 2014

sci
nm it is b :) despite its name, the radiator works by warming the air around it which rises and circulates around the room (convection)
December 1, 2014

algebra 2
13+x = +/- 5 sqrt(10) x = -13 +/- 5 sqrt(10)
December 1, 2014

sci
Heat goes from hot to cold by itself to move it from cold to hot requires work, like an air conditioner I would have chosen D
December 1, 2014

Math
m mN mN^2 mN^3 .......mN^(n-1) number on day n = m N^(n-1)
December 1, 2014

physics
force = change in momentum/change in time or m A if m is constant change in momentum/3 = 200 change in momentum = 3*200 kg m/s
December 1, 2014

math
12 x = 96 so x = 96/12 then 2 x + 2 (12) = perimeter
December 1, 2014

sci
yes microwaves are electromagnetic radiation
December 1, 2014

Science
14.) Answer = Habitat Destruction Yes 15.) Answer = Carbon Dioxide - I Think yes, Methane is worse but fossil fuels produce CO2 16.) Answer = ___________ reverse 17.) Answer = Ozone Layer yes 18.) Answer = ___________ non-point source 19.) Answer = ___________ cost - benefit ...
December 1, 2014

Rounding up and down
Here is the rationale I gave for an earlier problem, for what it is worth :) ========================= Math - Damon, Monday, December 1, 2014 at 2:08pm to the nearest tens place 55 would be called 60 54.9999999999 would be 50 but 55.00000000001 would be 60 so if it starts with...
December 1, 2014

Rounding up and down
if <5, then 0 if 5 or more, then 10 .34 2. .351 ---> .4 .562 ---> .6 .545 ---> .5 whew .445 ---> .4 3. .351 --> .35 .562 --> .56 .545 --> .55 ***** .445 --> .45
December 1, 2014

math....
distributive property of multiplication -p(p) + -p(-q) + -p(8) = -p^2 + pq - 8p
December 1, 2014

Calculus
You have to say what is the lower limit and what is the upper limit of your integral to do a definite integral I guess your function is f(x) = x for x < 1 and f(x) = 1/x for x >/= 1 (-2)^3 = -8 so when x<1 integral = -8 [x^2/2 upper-x^2/2 lower] and for x >/= 1 ...
December 1, 2014

Physics
capacitance = charge/unit voltage C = coulombs / volts
December 1, 2014

physics
Force = change in momentum/change in time 100 = change in momentum / 5 change in momentum = 500 Newton meters or Joules
December 1, 2014

Math
55 would be called 60 54.9999999999 would be 50 but 55.00000000001 would be 60 so if it starts with 55 it is 60 It does not make a whole lot of sense, but one must decide consistently :) 5 is 10 but 4.99999999 is 0
December 1, 2014

MATH
-9 - 3m -3m - m^2 = - m^2 - 6 m - 9
December 1, 2014

MATH
8 m - 8 n + 64 distributive property
December 1, 2014

Trig
Vs + Vc = 19.3 cos 33.7 i + 19.3 sin 33.7 j Vs = 17.5 cos 26.3 i + 17.5 sin 26.3 j so Vc x = 19.3 cos 33.7 - 17.5 cos 26.3 and Vc y = 19.3 sin 33.7 - 17.5 sin 26.3 |Vc|^2 = (Vc x)^2 + (Vc y)^2 tan angle N of E = Vc y/ Vc x of course in the real world navigators measure angles ...
December 1, 2014

Physics- formula help
if it is falling m g down positive F air resistance up a down positive Weight - Fair resistance = m a m a = m g - Fair resistance if the F air resistance were equal to the weight, mg , then the acceleration would be zero m (g-a)
December 1, 2014

CALC 1
you already have h', the first just take one more x e^x + e^x = e^x (x+1) e^x always + so where x + 1 is + x> -1
November 30, 2014

Calculus
My arithmetic was wrong, go with Steve !
November 30, 2014

Calculus
y = (3 -x^3)-(1/3) dy/dx = -(1/3) (3-x^3)^-2/3 (-3x^2) = + x^2 /(3-x^3)^(2/3) E
November 30, 2014

AP Calculus
since it is a cubic, there will presumably be two f' = 0 = 3 x^2 + 6 x = 3x ( x+2) x = 0 and x = -2 you find f(x) there
November 30, 2014

Calculus
top = (x+9)^.5 - 3 d top/dx = .5 (x-9)^-.5 ---> oo bottom = x d bottom/dx = 1 --->1 so ----> oo/1
November 30, 2014

Calculus,Reaction rates
at 1 second d = sqrt(10^2 + 10^2 + 5^2) = sqrt 225 d^2 = 100 + 25 t^2 + 100 t^2 d^2 = 100 + 250 t^2 2 d dd/dt = 500 t v = dd/dt = 250 t/d at t = 1 v = 250/15 = 16.7 ft/s
November 30, 2014

Calculus
x^2 f' + 2 x f = x [ x f' + 2 f ]
November 30, 2014

Calculus
dy/dx = slope = m for this ellipse 2 x dx/dx + 6 y dy/dx = 0 at(1,1) 2(1)+6(1)dy/dx = 0 dy/dx = m = -1/3 so y = -(1/3) x + b at (1,1) 1 = -1/3) + b b = 4/3 so y = -(1/3) x + 4/3 or 3 y - -x + 4
November 30, 2014

physics
V = Vi + a t 40 = 20 + 2 t t = 10 x = 20 t + (1/2) a t^2 x = 200 + 100 x = 200
November 30, 2014

physics
F = kX 25 (20/10)
November 30, 2014

Science
a = change in v/change in time a = 60/8.2 = 7.32 horizontal so horizontal force = 94*7.32 = 688 N vertical force up = weight = m g = 94*9.8 = 921 N net force = sqrt(921^2 + 688^2)
November 29, 2014

two step equation-fraction
if it is 4 + (m/3) = 5/6 then the answer is -19/2 which is -9 1/2 as Steve told you if it is (4 + m)/3 = 5/6 then the answer is -9/6 = -1 1/3 there is no perturbation I can make on what you typed to make it come out -3/2
November 29, 2014

two step equation-fraction
So maybe you typed the original question wrong maybe you meant: """"""""""""""""""" please help me step by step thanks (4+m)/3=5/6 """"""""&...
November 29, 2014

two step equation-fraction
6 m/3 = 2 m
November 29, 2014

chemistry
method is correct and I agree with the aritmetic
November 29, 2014

phyics
if board mass = m down force = m g so friction force must be m g mu F = m g F = m g/mu
November 29, 2014

Math
3 x dy/dx + 3 y -4 x +10 y dy/dx = 0 dy/dx (3 x+10y) = (4x-3y) dy/dx = (4x-3y)/(3x+10y)
November 29, 2014

chemistry
You just ignore the excess compounds. all that is important here is for every 2 mols of H2SO4 you get one mol of CaH4P2O8
November 29, 2014

chemistry
KOH = 39+16+1 = 56 grams/mol 14.3/56 = .255 mols .255/V = .55/1 V = .464 Liter
November 29, 2014

m
4(9) + 7(9) + 2 36 + 63 + 2
November 29, 2014

ph
work is force in direction of motion * distance moved so we need that angle between the motion and the force For the force: Tan theta = 5.8/3 theta = 62.65 degrees from x axis now the force is 100 deg from x axis so angle between force and motion = 100 - 62.65 = 37.35 so ...
November 29, 2014

Physics
I of bar around base of bar = (1/3) m L^2 = (1/3)(1.5)(.75)^2 = .281 kg m^2 initial angular momentum of bird around base of bar = m (2L/3)^2 [V/(2L/3)] = m (2L/3)V = .5 (.5)(2.25) = .5625 If the bird just stopped, then that is the angular momentum of the bar .5625 = I omega...
November 29, 2014

physics
time to fall: h = .5 g t^2 so t = sqrt (2 g h) time for sound to rise = h/c 5.3 = h/c + sqrt (2 g h) sqrt (2 g h) = 5.3 - h/c 2 g h = 5.3^3 - 10.6 (h/c) + h^2/c^2 look up c at 20 deg C and then solve the quadratic
November 29, 2014

Calculus I
for example see http://www.jiskha.com/display.cgi?id=1289778468
November 28, 2014

Calculus I
c = 10 x^2 + 4 x h but h = (100 - x^2)/4x c = 10 x^2 + 4x (100-x^2)/4x c = 10 x^2 + 100 - x^2 c = 9 x^2 + 100 cost is minimum as x goes to zero of course since the bottom material is so expensive. I have a hunch that the constraint should be on the volume, not the area.
November 28, 2014

pre-algebra
I could graph minutes on the x axis and pages read on the y axis so B is ok I could graph sandwiches on x and peanut butter on y I could graph toys on x and batteries on y HOWEVER oranges from a trip to the store is just a point.
November 28, 2014

Chemistry
p = 1.67*10^4 kilo Pascals V = 43.8 L T = 273 + 24 = 297 K R - 8.314 Liters kilopascals/deg K PV = n R T n = (1.67*10^4)(43.8)/ [ 8.314*297 ] n = 296 mols 296 * 40 grams/mol = 11840 grams or 11.84 kg
November 28, 2014

Physics
No, did you read what I wrote? You have to have an integral number of HALF wavelengths 2 m has one antinode in the middle 1 m has 2 antinodes at .25 and .75 .666666 m has 3 antinodes at 1/4, 1/2, and 3/4 (1.5 whole waves in there) .5 m has 2 whole waves in there, 4 antinodes ....
November 28, 2014

Physics
Try to draw a wavelength of .75 meters in your 1 meter string without a crest, not a node, at one end. D is allowed for sure, the lowest resonance. Draw it
November 28, 2014

Calculus
You are welcome.
November 28, 2014

Calculus
dy/dx = slope = 3 x^2 - 6 x + 5 where is that max or min ? where its derivative is 0 d^2y/dx^2 = 0 = 6 x - 6 so x = 1 is that a max or a min? take the ext derivative, if + it will be headed up and a min. d^3y/dx^3 = 6 that is positive so the min slope is at x = 1 that slope is...
November 28, 2014

Math typo
.... she walks 1 1/4 of an hour. Huh?
November 28, 2014

Physics
It only weighs about 270 N if 27 kg He is pulling with 454 N That is not right unless it is hooked to an anchor. It should probably be 270 kg for about 2700 N weight
November 28, 2014

Physics
Normal force on floor = m g - 454 sin 37 friction force = mu * normal force but friction force = 363 N you said so 363 = mu (27*9.8 - 454 sin 37)
November 28, 2014

Physics
ah, as happy as he ever got that is.
November 28, 2014

Physics
By the way I went to some pain to elaborate on this because a scientist named Edward Teller (Google him) asked me that very question in a slightly different manner when I was interviewing for a fellowship many years ago. I gave him the answer I just gave you and he was happy :)
November 28, 2014

Physics
It is very hard for a wave to change frequency. You have to store some of the waves somewhere if you do that because in the end the same number must enter one end of the box as come out the other. Think ocean waves coming into a beach, They slow down in the shallow water so ...
November 28, 2014

physics
Cut line, 2/3 and 1/3 Secure end of shorter line to tree. Reeve through block at car and secure to the hook on your second block which will be a traveling block Now secure the end of your longer line to the tree Run that line through the sheeve on the traveling block now look ...
November 28, 2014

Physics
(specific gravity of this oil*7 + 8)62.4 in pounds/ft^2 divide by 144 to get psi, pounds per square inch I do not know the ratio of this oil density to that of water
November 28, 2014

Calculus
How do we know h = 15 ? If we do not know h, then the solution is something that looks like a space needle :) L * w * h = 2160 if h = 15 L * w = 144 L = 144/w cost = c = 5(L*w) + 2 L*h + 2 w*h c = 5 L w + 2 w h + 2 L h if we know h = 15, then c = 5 L w + 30 w + 30 L c = 5*144...
November 28, 2014

Math
sin 63 = h/25
November 28, 2014

Alg !
http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html
November 28, 2014

whoops
1 = 1/24 r^3 r^3 = 24 r = 2 sqrt 3 again can not be both
November 28, 2014

math
a r^2 = 9 a so r = 3 ar = (1/24) a r^4 r = (1/24) r^3 24 = r^2 but r = 3, can not be 3 and sqrt 24 a r^3 is fourth term 27 a = ? 48 ? a = 48/27 ? I think you have this messed up.
November 28, 2014

English
yes
November 28, 2014

math
a ar^1 ar^2 ar^3 ----- ar^(n-1) ar^2 = 9a so a = 3 a r = (1/24) a r^4 r = (1/24) r^4 r^3 = 24 = 8*3 remember this so r = 2 *3^(1/3) fourth = a r^3 = 3 *24 = 72
November 28, 2014

calculus
a = -g = -9.8 m/s^2 The statement gives you the answer. v = integral a dt = -9.8 t + c at t = 0 v = Vi = 5 m/s so c = 5 v = -9.8 t + 5 h = integral v dt = 5 t -(9.8)/2 t^2 + cc when t = 0 h = Hi = 442 so cc = 442 h = 442 + 5 t - 4.9 t^2 (check your physics book :) at top, v = ...
November 28, 2014

physics, how to find the height
At max height all velocity is horizontal u = 26 but u = 65 cos Theta so Theta, the angle shot above horizontal = 66.4 deg so Vi = initial up speed = 65 sin Theta = 59.6 at top vertical speed = 0 so 0 = 59.6 - 9.8 t where t is rise time t = 6.08 seconds going up H = 0 + 59.6 t...
November 27, 2014

physics
Vi = 2.7 m/s h = 11 + 2.7 t = 4.9 t^2 0 = 11 + 2.7 t - 4.9 t^2 at ground 4.9 t^2 - 2.7 t - 11 = 0 t = [ 2.7 +/- sqt (2.7^2 +44*4.9) ]/9.8
November 27, 2014

Math
been there, done that http://www.jiskha.com/display.cgi?id=1417133335
November 27, 2014

physics
24 = (1/2)g t^2 48 = 9.8 t^2 t 2.21 seconds
November 27, 2014

algebra
.3 a + .8 b = .4 * 10 a + b = 10 .3 a + .8 b = 4 .8 a + .8 b = 8 ---------------- subtract -.5 a = - 4 a = 8 so b = 2
November 27, 2014

Pre-Calc.
LOL, but if two angles are 60 then so is the third and it is an equilateral triangle :) base = 24 12^2 + h^2 = 24^2 h^2 = -(3*4)^2 + (6 *4)^2 h^2 = 4^2 ( -9+36) = 4^2 (27) = 4^2*3^3 h = 4*3 * sqrt 3 h = 12 sqrt 3
November 27, 2014

physics
The mechanical energy of the system is the sum of kinetic and potential energy. In this ideal world it does not change with time. Since you found the maximum speed use (1/2) m v^2
November 27, 2014

math
a b c c = 2 a a + b + c = 14 a b 2a 3 a + b = 14 ones digit is even 1 b 2 ---> 3+b=14, b = 11 no 2 b 4 ----> 6 + b =14, b = 8 ok so 2 8 4
November 27, 2014

math
1 2 4 8 16 1 2^1 2^2 2^3 2^(n-1) a a2^1 a 2^2 .... geometric sequence with a = 1 r = 2 n = number of days 2^59 = area 2^x = 2^59/2 x = n-1 = 58 so 59 days which we could have said right off because if you cover the whole lake in 60 days then the day before you must have half ...
November 27, 2014

algebra 2
16 x^2 - 56 x = 0 x (16 x^2 - 56 ) = 0 x = 0 or x = 56/16
November 27, 2014

math
a ar^1 ar^2 ar^3 .... ar^(n-1) so a r^2 = 9 a a r^1 = (1/24)ar^4 ----------------------- ----------------------- so r = 3 a(3) = (1/24)a (3)^4 This is not possible. You have a typo.
November 27, 2014

Math
You are welcome.
November 27, 2014

Math
3/2 = L/b = 1.5/b 3 b = 3 b = 1
November 27, 2014

Physics
F = m a weight = m a a = -mg/m = - g in other words acceleration is down at -10 m/s^2 dv/dt = a = -10 so v = -10 t + c but at t = 0, v = +10 so c = 10 and v = -10 t + 10 now at the top, v = 0 0 = -10 t + 10 so at the top when t = 1 if v = -10 t + 10 then h = Hi + 10 t - 5 t^2 ...
November 27, 2014

math
I do not have a politically correct answer to your preamble question.
November 27, 2014

math
2 x + 3 y = 92 4 x - 7 y = 2 4 x + 6 y = 184 4 x - 7 y = 2 --------------------- 13 y = 182 y = 14 etc
November 27, 2014

physics
a quantity that has both magnitude and direction. for example you can measure the speed or magnitude of velocity of a car with a speedometer. However to specify the velocity vector you also need a compass. 20 km/hour is a scalar magnitude, speed 20 km/hour EAST is a vector.
November 27, 2014

physics, how to find the height
a = -g with g unknown at h = 0, Pe = 0 and Ke = (1/2)m Vi^2 = total energy at h = Htop , v = o and Pe = m g Htop = (1/2) m Vi^2 so Htop = Vi^2/2g at h = Htop/4 Pe = m g (Htop/4) = m Vi^2/8 total energy still = m Vi^2/2 so Ke = (3/4) (1/2)m Vi^2 so it still has (3/4) of initial...
November 26, 2014

U.S. History Help!!!!!!!
1 c I think (there were a lot of tories) 2 a 3 d
November 26, 2014

Math
.70 p = 72.09 p = 72.09/.7 = 102.99
November 26, 2014

Language Arts
I would pick B.
November 26, 2014

Statistics
http://davidmlane.com/hyperstat/z_table.html
November 26, 2014

six sigma
http://davidmlane.com/hyperstat/z_table.html
November 26, 2014

physics
vertical problem Vi = 2390 sin 49.6 v = Vi - 9.8 t at top v = 0 so t = Vi/9.8 at top that is half the trip hits ground at tg = Vi/4.9 Now the horizontal problem u = 2390 sin 49.6 range = u tg range = 2390 sin 49.6 * Vi/4.9 so range = 2390^2 sin 49.6 cos49.6 /4.9 = 575369 ...
November 26, 2014

math
9/30 = 3/10
November 26, 2014

Bus. Math
s - .55 s = 5.12 .45 s = 5.12 s = 11.38 check 5.12 + .55(11.38) = 11.38
November 26, 2014

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