Tuesday
August 4, 2015

Posts by Damon


Total # Posts: 21,627

Physics - must know all masses
insufficient information
January 30, 2015

Physics
F = G Mearth Moject / r^2 F1 = G Mearth m/6400^2 F2 = G Mearth m/6780^2 so F2/F1 = (6400/6780)^2 = 0.891
January 27, 2015

math
150 C (95-0) = 21 (heat of fusion of ice) where C is heat capacity of iron about 0.450 J/ g deg c
January 27, 2015

Math - Problem solving
last year = x this year = x+20 x = 0.75(x+20)
January 27, 2015

COMBINED OPERATION ON FRACTIONS
(3/5)j +(3/4)(2/5)j + 3 = j
January 27, 2015

physics
both angular and linear momentum are conserved. The center of gravity of the system is height: h (m+m) = m x + m (L/2) and it is moving at speed Ucg (m+m) = u m then of course you have the rotation about the cg
January 27, 2015

Math
the area of the base is easy w*L if the height is h then two of the slope triangles have base w and height along the slope of sqrt(h^2 + L^2/4) so the sum of those two triangle areas is w *sqrt(h^2 + L^2/4) similarly the sum of the other two triangle areas is L * sqrt (h^2 + w...
January 27, 2015

Math / Algebra
I agree
January 27, 2015

algebra
-y = 18 * 7 y = -18 * 7
January 27, 2015

Math word problems
100 - 25 = 75 so you took 25 off every hundred In other words, 25% discount another way to do it: 160 - 120 = 40 dollars discount 100 (40/160) = 25 %
January 27, 2015

Science
If you look at the inside of a tree branch or tap maple sap you see straw like tubes that transport fluid around.
January 27, 2015

Physics - Vectors
|A| |B| cos theta = A dot B 2.2 * 10 * cos theta = 14 theta = cos^-1 (14/22) theta = 50.5 degrees
January 26, 2015

Math
x = 2log4 y log4 y = (x/2) 4^log4 y = 4^(x/2) y = 4^.5x
January 21, 2015

math
1.75 inches ( 45 miles/2.25 inches) =
January 21, 2015

physical
(1/2)m v^2 = m g h so v = sqrt (2 g h) remember that
January 21, 2015

physics
Google Millikan oil drop experiment for example: http://ffden-2.phys.uaf.edu/212_fall2003.web.dir/Ryan_McAllister/Slide3.htm
January 21, 2015

math
the absolute value of (sec x)^2 is just sec^2 x because when you square a number it is positive so we have (1/cos^2) sin / [1/sin] or tan^2 x dx = tan x - x + c
January 19, 2015

physics
calculate F = Q E do a = F/m to get a, the acceleration then plain old constant acceleration x = (1/2) a t^2
January 19, 2015

Civics
YES !!!!!
January 19, 2015

Civics
Google Marbury vs Madison
January 19, 2015

Physics
x = 2 + 3.2 t - 3.85 t^2 when is v = 0? dx/dt = v = 3.2 - 7.7 t v = 0 when t = 3.2/7.7 = .416 seconds then x = 2 + 1.33 - .665 = 2.66 If you do not know calculus, find the vertex of the original equation.
January 19, 2015

Physics
d = Vi t + (1/2) a t^2 98.3 = 29 t - 1.8 t^2 1.8 t^2 -29 t + 98.3 = 0 solve quadratic for t [ 29 +/- sqrt ( 841 - 708) ] /3.6 [ 29 +/- 11.5 ] / 3.6 = 4.86 (ignore the big time, it is on the way back :)
January 19, 2015

Civics
14 says they have the right to go to school just as other citizens do. 13 just says they are not slaves any more.
January 19, 2015

Civics
I would say 14 which does not allow sates to deny privileges to any citizens.
January 19, 2015

ap calc
(z^2)^(1/2) = z you have (x^2 - 4) dx x^3/3 - 4 x + C
January 19, 2015

Math
I am an engineering teacher not a civics teacher jeje.
January 19, 2015

Math
(4/5)(7/8) = 7/10
January 19, 2015

Algebra
s = side length x = long length 2 s + x = 1600 so x = (1600-2s) 2 s (5) + x (20) = 13,000 10 s + 20 (1600-2s) = 13,000
January 19, 2015

physics
By the way to do the second one you must know the density of the fluid. These are very strange questions. Are you sure you have copied them correctly?
January 19, 2015

physics
I do not know. All I know is the ratio of areas. 80 (pi r^2) = 1300 (pi R^2)
January 19, 2015

SCIENCE
3. An electric engineer might (1 point) Build a dam to provide a source of hydroelectric power.*** Develop new fuels to use in the next generation of fuel-efficient cars. Design a remote-controlled toy race car. Design an airplane wing that changes shape to increase stability...
January 19, 2015

Physics
at the same acceleration as (one g about 9.8 m/s^2)
January 19, 2015

physical science
------>------> = ------------> <----- ------> = 0
January 19, 2015

physics
F * d = work done by friction = initial Ke = (1/2) m v^2 F * 50 = (1/2)(750)(900) 100 F = 750 * 900 F = 750 * 9 There are harder ways of course using F = change of momentum/ time = 750*30/t then 50 = (1/2)a t^2 where a = 30/t so 100 = 30 t t = 10/3 seconds to stop a = 9 m/s^2...
January 19, 2015

Physics
56.1 mi/h = 25.1 m/s v = Vi - a t 0 = 25.1 - a t so t = 25.1/a d = (1/2) a t^2 206 = a t^2 206 = a(630/a^2) = 630/a a = 3.06 m/s^2 (negative of course)
January 19, 2015

Physics
h = (1/2) g t^2 = 4.9 (3.12)^2
January 19, 2015

Physics
d = (1/2) a t^2 194 = 6.60 t^2 solve for t then v = Vi - 6.60 t = 0 at end Vi = 6.60 t
January 19, 2015

Physics
v = Vi + a t 104/3.6 = 74/3.6 + 1.52 t
January 19, 2015

ap calc
d/dx (2x+7)) = 2 so the 1/2 gets rid of the 2
January 19, 2015

Physics
but you forgot the work done against gravity m g * 500 = .05 * 9.81 * 500 = 245 J 1450 - 245 = 1204 J so 1204 = .05 * a * 500 =============================== The second one looks ok
January 18, 2015

physics
Aaaarrrgghhhhh !!!!! Joey is right. At the top v = 0, no velocity except that of mother earth spinning on her axis and making her way around the sun. The acceleration is constant, -9.81 m/s^2 the whole time. Charlie could not possibly, any way, be more wrong. Send him to his ...
January 18, 2015

Physics
t = 4.2 T = 8 a = 5 I guess it started from a dead stop. x = (1/2) a t^2 during acceleration Vi = speed at end of acceleration = a t X = Vi T during constant speed so distance = (1/2) a t^2 + Vi T
January 17, 2015

Math
32 = 8 * 4 56 = 8 * 7 so 32 + 56 = 8 (4+7)
January 15, 2015

MATH
how much of the 40 hours he works at each job
January 15, 2015

Torque
Huh? 30 * 1.5 = 45 BUT 60 * 1 = 60
January 15, 2015

physicsss
You are welcome.
January 15, 2015

physicsss
If the velocity is constant you are correct.
January 15, 2015

Physics
work done in stopping = brake force * 75 meters (1/2) m v^2 = work done by brakes (1/2) m (93)^2 = F * 75 F = m (57.66) but F = ma so a = 57.66 that is the acceleration the tires can give you. Use it for centripetal acceleration a = 57.66 = v^2/r r = (93)^2/57.66
January 15, 2015

Physics
mu m g = m v^2/r = m omega^2 r mu g = omega^2 r omega = 2 *2pi radians/s = 4 pi rad/s mu = .4 g = 9.81 so r = .4 * 9.81 /16 pi^2 = .0248 meters = 2.5 cm
January 15, 2015

Physics
m v2/r
January 15, 2015

No picture
If you drew a picture, we can not see it.
January 15, 2015

Alegebra
Huh? how can it be even and 9 ????
January 15, 2015

physics
Without friction, the angular velocity will not change. In real fife of course it will. Even in the vacuum there is loss of kinetic energy to the bearings. However as far as the information given here, the answer is constant angular velocity forever. or at least for a very ...
January 15, 2015

Physics
Vi = 15 sin 30 = 7.5 v = Vi - gt v = 0 at top so g t = 7.5 t = 7.5/9.8 = about .77 s
January 15, 2015

Calculus POwer RUle
dy/dx = -3 k x^2 3 = -3 k (4) k = -1/4
January 14, 2015

Math
b = 2 r b - r = 24 2 r - r = 24 r = 24 b = 48
January 14, 2015

math
16 x = x^2 x^2 -16 x = 0 x(x-16) = 0 x = 0 or x = 16 y = 0 or y = 256 (0,0) and (16 , 256)
January 14, 2015

calculus
If 5x2 + y4 = -9 then evaluate d^2y/dx^2 when x = 2 and y = 1 5 x^2 + y^4 = -9 10 x + 4 y^3 dy/dx = 0 so dy/dx = -2.5 x/y^3 d^2y/dx^2=-2.5[ y^3 - 3 x y^2 dy/dx]/y^6 at (2,1) dy/dx = -2.5(2/1) = -5 so d^2y/dx^2=-2.5[1-6(-5)]/1 = -2.5 [ 31] = - 77.5
January 14, 2015

calculus
Find the slope of the graph of the relation x2y + 4y = 8 at the point (2, 1) (x^2+4)y = 8 (x^2+4)dy/dx + y (2x) = 0 8 dy/dx + 4 = 0 dy/dx = -1/2
January 14, 2015

calculus
f(x)=(x+1)^2x d/dx u^v = v u^(v-1)du/dx + u^v lnu dv/dx so f'=2x(x+1)^(2x-1) + 2(x+1)^2x ln(x+1)
January 14, 2015

calculus
x^2 + y^2 = 2 x y 2 x + 2 y dy/dx = 2 x dy/dx + 2 y dy/dx (y-x) = y-x dy/dx = 1 easier way without using calculus: x^2-2xy+y^2 = 0 (x-y)(x-y) = 0 x = y slope = 1
January 14, 2015

calculus
y = 7 x^6 cos^-1 x f' = 7[ x^6 (1/(1-x^2)) + 6x^5 cos^-1 x ] = 7 x^6/(1-x^2) + 42x^5 cos^-1 x
January 14, 2015

history
LOL - well, to start with which ? TR or FDR ? You better Google which ever president you mean because it would take all night to summarize.
January 14, 2015

science
NaCl = 23 + 35 = 58 g/mol 22/58 = .379 mol .379 mol/ .2 liter = 1.9 M
January 14, 2015

Math
Get it now. When you subtract you reverse the sign of the bottom one and add.
January 14, 2015

Math
y=-x+4 y=-2x-4 ------------- SUBTRACT these two equations 0 = -x -(-2x) + 4 - (-4) 0 = -x + 2x + 4 + 4 0 = x + 8 x = -8
January 14, 2015

Math
y = -x + 4 y = -(-8) + 4
January 14, 2015

Math
for elimination subtract as is y=-x+4 y=-2x-4 ------------- 0 = 1 x + 8 so x = -8 then get y = 8+4 = 12
January 14, 2015

Math
I did the earlier ones with elimination here is substitution y = (-x+4) so (-x+4) = -2x - 4 x = -8 then go back and get y y = -x + 4 = 8+4 = 12
January 14, 2015

Math
You are welcome.
January 14, 2015

Math
10 x - 8 y = 20 -10 x + 2 y = -20 ----------------- add 6 y = 0 y = 0 if y = 0 5 x = 10 x = 2 so the two lines intersect at (2 , 0)
January 14, 2015

calculus
1. If f(x) = ln(1 - 2x), then find f '(x) f' = [ 1/(1-2x) ]( -2) = -2/(1-2x) = 2/(2x-1) I do not understand your second function
January 14, 2015

Math
check it then 2 (9) - 5 (-7) = 53 ? yes -9 +5(-7) = -44 ? yes so it is right, why ask ? :)
January 14, 2015

Calculus
x = 15 t h = 5 t + 5 = 5(t+1) y^2=x^2+h^2 = 225t^2 + 25t^2 + 50 t + 25 y^2 = 250 t^2 + 50 t + 25 2 y dy/dt = 500 t + 50 now at t = 3 y^2 = 250(9)+150 +25 = 2425 y = 49.2 so 2(49.2) dy/dt = 1500 + 50 = 1550 dy/dt = 15.8 m/s
January 14, 2015

Math
add the two equations as is x = -10 5 y = 50 y = 10
January 14, 2015

physics
easier way work done = final (1/2) m v^2 4310 = (1/2)2520 v^2 v = 1.85 m/s ;)
January 14, 2015

physics
change of momentum = 2520 v average force = change of momentum/time F = 2520 v/t work = force * distance 4310 = 2520 v/t * 22.4 or v/t = .0764 or t = v/.0764 now if force were constant d = (1/2) a t^2 44.8 = a t^2 v = a t so a = v/t so 44.8 = v t = v^2/.0764 v^2 = 3.42 v = 1....
January 14, 2015

Sixth Grade Math
m = p - 3 = 51 - 3 = 48 yes, you did it right. Either the question was meant to be confusing or the person who wrote the question never asked the more complicated question he/she had in mind :)
January 14, 2015

Socal Studies
sorry: http://science.kqed.org/quest/2007/12/12/snakes-are-not-poisonous/
January 14, 2015

physics
mass has nothing to do with this work = force * distance in direction of force = 4.67 * 10^5 * 528 Joules
January 14, 2015

Math
multiply the second equation by 2 5 x - 4 y = 10 -20x +4 y = -40 ------------------ mow add -15 x = -30 x = 2 etc
January 14, 2015

history
You are welcome.
January 14, 2015

history
here: http://en.wikipedia.org/wiki/Iron_Brigade and Texas was very, very important to the Confederacy.
January 14, 2015

history
Oh my, oh my, you better Google Minnesota and Michigan Gettysburg
January 14, 2015

Math
24.8 / 0.6 = 41.3
January 14, 2015

Math
100 * 1382.5/27650 = 5 %
January 14, 2015

english
http://www.jiskha.com/display.cgi?id=1421282361
January 14, 2015

english
I did, scroll down to where you first posted this question.
January 14, 2015

english
( It is a real marine biology subject )
January 14, 2015

english
I gave you a reference for the lobster and the cod. Try. Read the article and see if you can come up with something.
January 14, 2015

us history
http://www.bostonmassacre.net/timeline.htm
January 14, 2015

English
might help: http://www.gma.org/lobsters/allaboutlobsters/society.html
January 14, 2015

English
Do cod eat baby lobsters? Do lobsters eat cod fingerlings? Are populations of both species likely to peak at the same time? ( I am more into math than English. )
January 14, 2015

chemistry
P1 V1 = P2 V2 P2 = 3 P1 P1 V1 = 3 P1 V2 so V2 = V1/3 = 5/3 liters
January 14, 2015

Math
(25/1000)(112000 = 2,800
January 14, 2015

math
1.325/.304 = 4.4
January 14, 2015

math
1.333 *1000 feet * (1 mile/5280 feet) = 1333/5280 = 0.2525 miles = 0.25 a little over a thousand feet is a little over a quarter of a mile by the way the Marianas Trench is more like 30,000 feet deep or over five miles
January 14, 2015

algebra
s = 2 k s-10 + k-10 = 23 s + k = 43 2 k + k = 43 3 k = 43 k = 43/3 = 14 1/3 s = 28 2/3
January 14, 2015

science
1. charged 2. pull 3. motion, work, potential energy(voltage), kinetic energy - beats me what they want her to say
January 14, 2015

Hist
It is not d.
January 14, 2015

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