Saturday
August 23, 2014

Posts by Damon


Total # Posts: 17,980

science
I think I know what you mean. If you calculated the time until the ball reached maximum height and called that time t, then the total time in the air is 2t by symmetry
August 8, 2014

science
yes they both start with Vi = 0 and accelerate downward at 9.81 m/s^2
August 8, 2014

Physics
You are welcome.
August 8, 2014

Physics
yes, 0 = 42 + 75 a a = - .56 d = Vi t + .5 a t^2 d = 42(75) - .28(75)^2 = 3150 - 1575 = 1575
August 8, 2014

History
I do not see a problem in using the same things as answers an earlier question. You have me pretty confused though about what you think are advantages and disadvantages of ethnic neighborhoods. What do you think are advantages and what do you think are drawbacks?
August 7, 2014

History
cultural diversity and learning new cultures would not particularly be an advantage of an ethnic neighborhood. A family that moved into a mixed neighborhood would probably learn the new language and traditions faster. I would say advantages include mutual support both in ...
August 7, 2014

what is the question ?
You want zeros of y or what? if zeros: 4 x^2 - 12 x + 9 = 0 (2 x-3)(2x-3) = 0 x = 1.5, 1.5 double root If vertex etc: 4 x^2 -12 x = y - 9 x^2 - 3 y = (1/4)(y-9) x^2 - 3 y + 9/4 = (1/4)y (x-1.5)^2 = y/4 vertex at (1.5 , 0) which we knew already
August 7, 2014

physics
Well, there is a hard way and an easy way. Easy way height = h angle = A with no friction KE gained in slide = m g h (1/2) m v^2 = m g h v = sqrt (2 g h) average speed = v/2 = .5 sqrt (2 g h) time = average speed * h/sin A t = .5 h sqrt (2 g h) /sin A now with work done ...
August 7, 2014

math
12.5= 3/k multiply both sides by k 12.5 k = 3 divide both sides by 12.5 k = 3 / 12.5
August 7, 2014

physics whoops
Whoops, sorry, Steve is right.
August 7, 2014

physics
since the total displacement vector is zero the average speed is zero. let i be unit vector from point A to point B velocity outbound = 40 i velocity back = -60 i (40 - 60)/2 = -10
August 7, 2014

Math
5*4
August 7, 2014

Math
I did one of these for you. They are fundamentally all the same. The circumference of a circle is 2 pi r The area of a circle is pi r^2 Hey, draw a picture.
August 7, 2014

Math
6 w = 18 w = 3 so r = 3 A = pi r^2 = 9 pi
August 7, 2014

math
16 * 8 * 8
August 6, 2014

math corrections
I do not understand number 2. Typo? 4) .75/2 -.625/2 = .0625 (radius not diameter is used) 14) I get 40 (long, will elaborate later) 24) (30/250)(30) = 3.6
August 6, 2014

Algebra
2.68*10^-5 watts/cm^2 to dB You want Watts/m^2 so multiply by 10^4 2.68 * 10^-1 Watts/m^2 definition of dB for sound: dB = 10 log (watts/m^2 intensity /10^-12) = 10 log (2.68*10^11) =10 [ log 2.68 + 11 ] = 10 [ 11.428 ] = 114 dB LOUD !!!!
August 6, 2014

Physics
displacement vector / time
August 6, 2014

physics
Force = change in momentum / change in time if force the same and time the same then change in momentum the same (answer to first question) f = m v /t f = 2 m V /t so V = v/2 Ke of little mass = (1/2) m v^2 Ke of big mass = (1/2) 2m v^2/4 =(1/2)m v^2/2 so Ke of big mass = 1/2 ...
August 6, 2014

PHYSICS
increase of potential energy of block = m g h = (2.515)(9.81)(.15) = 3.70 Joules so (1/2) m v^2 = 3.7 Joules at bottom (1/2)(2.515)v^2 = 3.7 v = 1.72 m/s at bottom after collision momentum after collision = 2.515 * 1.72 = 4.31 g m/s momentum before collision = .015 v so v = 4....
August 6, 2014

physics
change those to meters / second (1/2) m (V2^2-V1^2) note 6^2 - 5^2 = 36-25 = 11 but 3^2 - 1^2 = 9 - 1 = 8
August 6, 2014

physics
v = sqrt (2 g h) = sqrt (2 * 9.81*12) a ) Ke = (1/2)(45) v^2 b ) stops in .32 m work = Force * .32 = Ke from part a
August 6, 2014

physics
momentum down = 1.2 *25 momentum up = 1.2 * 10 change of momentum = 1.2 (25 + 10) impulse is change of momentum Force = change in momentum/change in time = answer to part a / .2
August 6, 2014

statistics
I get .8186 between 24 and 48 so about 819 out of 1000
August 6, 2014

statistics
http://davidmlane.com/hyperstat/z_table.html
August 6, 2014

SCIENCE
http://www.jiskha.com/display.cgi?id=1407333641
August 6, 2014

SCIENCE
aaarrrgghhh 1.5 (9.81) h = 29.4 still
August 6, 2014

PHYSICS
work = increase in kinetic energy = (1/2)(18,000) (40^2 -30^2) in Joules force * distance = work in Joules distance = average speed * time d = 35 * 5 so Force = work from part a / d power = work/time = work from part a / 5 seconds in Joules/sec which is Watts
August 6, 2014

PHYSICS
You are welcome.
August 6, 2014

PHYSICS
http://www.jiskha.com/display.cgi?id=1407324138
August 6, 2014

PHYSICS
Hey, I just did this
August 6, 2014

PHYSICS
Newton #2 is Force = rate of change of momentum 6 = 3 (v-0) /10 solve for v final momentum = m v
August 6, 2014

PHYSICS
I guess it is hanging down on earth where g = 9.81 m/s^2 approximately F = m g = k x 2.5 * 9.81 = k (.42) solve for k b) F = k (0.50) c) U = (1/2) k x^2 = (1/2)(k)(0.35)^2
August 6, 2014

SCIENCE
m g h = 29.4 1.5 * 9.81 * h = 29.4 solve for h
August 6, 2014

math
Looks like magic to me.
August 6, 2014

Physics
no kinetic energy lost in collision Not only is momentum conserved but also sum of (1/2) m v^2
August 6, 2014

Physics
1) sqrt (20^2 + 30^2) 2) no horizontal force so no change in horizontal speed 3) slows to zero at top then comes back to original speed but downward 4) Like we said in #2, it is the same until it hits the charging warthog. 5) it is at max height, no speed up any more and no ...
August 6, 2014

Physics
.005 (300) = - 3 v v = -.5 Ke = (1/2)(.005)(300)^2 + (1/2)(3)(-.5)^2
August 6, 2014

math
Hey, look, you are not paying attention. it has highest power of 3 so three factors and three zeros however one of those zeros is repeated, x = -1 so zeros are -1, -1 , -1/2 and the three factors are (x+1) (x+1) (2x+1) now check by multiplying those three factors and see if ...
August 6, 2014

math
I gave you the whole thing factored (x+1)(2x+1)(x+1) zeros are -1 , -1/2, -1
August 6, 2014

math
try x = -1 for a zero 2(-1) + 5(1) + 4 (-1) + 1 -2 + 5 - 4 + 1 0 so (x+1) is a factor, now divide (x+1)(2x^2 + 3x + 1) (x+1)(2x+1)(x+1)
August 6, 2014

physics
He has a Uranium mine.
August 6, 2014

physics
mass irrelevant 78.4 = (1/2) g t^2 t^2 = 2 * 78.4 / 9.81
August 6, 2014

Copy and paste does not work here
We can see neither your equation nor the "following statements".
August 6, 2014

math
(1/5)(V+W+X+Y+Z)
August 6, 2014

Math
2(81) - 3(9) - 8(3) + 4 = 115
August 5, 2014

math
3 - 4 - 2 - 8/15 -45/15 -8/15 -53/15
August 5, 2014

physics
The horizontal component of velocity DOES NOT CHANGE There is no horizontal force. Therefore there is no horizontal acceleration.
August 5, 2014

Finance Help
In the end, looking far ahead, the value of a share of a company is the present value of a future stream of dividends. Of course people do not think much about that for most stocks, particularly those that presently pay no dividends, because there are so many other factors ...
August 5, 2014

Math
Nope, C 1.5 inches
August 5, 2014

Math
L = 10 - 2x w = 8 - 2 x v = L * w * x v = (10-2x)(8-2x)x v = (80 - 36 x + 4 x^2)x v = 4 x^3 - 36 x^2 + 80 x do you do calculus? if so the min or max when dv/dx = 0 0 = 12 x^2 -72 x + 80 0 = 3 x^2 - 18 x + 20 x = 3 +/- (1/3)sqrt 21 = 3 +/- 1.52 the plus sign is too big a width ...
August 5, 2014

History
You are welcome ;)
August 5, 2014

History
How much does this machinery cost? Assuming money was borrowed from the bank to buy it all, how do the loan payments compare with the monthly payments to the bank for the farm land and the house and barn? Does the cost of this equipment force you to buy a much bigger farm than...
August 5, 2014

Algebra
149.25 = x - 0.25 x 149.25 = 0.75 x x = 149.25 / 0.75
August 5, 2014

math hw
20/60 = 1/3 of an hour distance = speed * time 160 miles = speed * (1/3) hour speed = 3 * 160 miles/hour = 480 miles/hour
August 5, 2014

Pre Cal
100 at 50 degrees counterclockwise from x 50 at 160 counterclockwise from x x component = 100 cos 50 + 50 cos 160 = 64.28 - 46.98 = 17.30 y component =100 sin 50 + 50 sin 160 = 76.60 + 17.10 = 93.70 magnitude = sqrt (17.30^2 + 93.70^2) angle = tan^-1 (93.70/17.30)
August 5, 2014

Math
You are welcome. Good luck !
August 5, 2014

Math
Here: http://www.purplemath.com/modules/mtrxmult.htm
August 5, 2014

Math
|24 -12| |0 +3 | |-18 -9|
August 5, 2014

Math
Well, if you multiply a matrix by a scalar, you multiply every element by the scalar
August 5, 2014

Math
Perhaps nothing. I need to figure out what the question is :)
August 5, 2014

Math
Oh like this? | -8 +4 | -3| +0 +3 | | +6 +3 | now does it want the product or -3 times the determinant I wonder ?
August 5, 2014

Math
Anyway --- go here : http://matrixcalc.org/en/
August 5, 2014

Math
can you describe it in words? is it a single matrix like | -8 +4 | | +0 +3 | | +6 +3 | and you want something about it ?
August 5, 2014

Math ?????
I have no idea what you are doing. Are those vectors or matrices or what ?
August 5, 2014

Alegbra
T >/= -6
August 5, 2014

Alegbra - Ms Sue
Ms Sue, negative divide changes arrow direction.
August 5, 2014

Alegbra
5 > 4 - 2 y 1 > -2 y divide by -2, when you multiply or divide by a negative, change direction of arrow - 1/2 < y so y > -1/2 now check that by picking some y which is greater than (to the right of on number line) -1/2 like maybe -1/4 8 - 3 > 4 - 2(-1/4) ???? 5...
August 5, 2014

physics
call north y and east x phase one: vx1 = 40.6 cos 25 vy1 = 40.6 sin 25 x1 = 40.6 cos 25 * 3 y1 = 40.6 sin 25 * 3 Phase 2 vx2 = 0 vy2 = 23 x2 = x1 + 0 * 7.4 y2 = y1 + 23 * 7.4 d = sqrt (x2^2 + y2^2)
August 5, 2014

Physics
50 meters plus whatever, find whatever v = Vi - 0.981 t v = 0 at max height so t = 30 m/s / 9.81 m/s^2 t = 3.06 seconds upward h = 50 + Vi t - 4.9 t^2 h = 50 + 30 (3.06) - 4.9 (3.06)^2
August 5, 2014

Calculus-Math
A = 2 (t+1)(t^.5) dA/dt = 2 [ (t+1)(.5 t^-.5) + t^.5 (1) ] = 2 [ .5 t^.5 +.5 t^-.5 + t^.5 ] = 2 [ 1.5 t^.5 + .5 t^-.5 ] = 3 sqrt t + 1/sqrt t = (3 t + 1 )/sqrt t
August 5, 2014

Math
10/12 + 9/12 = 19/12
August 5, 2014

Geometry
I am not sure how to do a two column proof of this. If the word "image" or "model" implies similarity, then it is just a one line proof; if it is a valid image, then the model and the bicycle are similar. (angles are the same and lengths are proportional.)
August 5, 2014

Geometry
If corresponding angles are the same and if all corresponding lengths are in the same ratio then the images are similar.
August 5, 2014

Geometry
The image is similar (in the geometrical sense) to the original. Therefore if any length on one image is 9 times its length on the other image, then all lengths are in that ratio. Use any length, for example the diameter of the front wheel on each image :)
August 5, 2014

Economics
Nope
August 5, 2014

economics
1. costs money, employs bureaucrats 2. keeps people alive, employs bureaucrats
August 5, 2014

Afrikaaans
Ik ken een beetje Nederlands en ik versta je wel, maar wat heb je nodig? Wij kunnen een essay over je school niet schrijven. Ik weet niets over je school.
August 5, 2014

geometry
did you leave out the 3 120s that go with the three 50 s ?
August 5, 2014

geometry
the exterior angles have to sum to 360, all the way around with exterior of 50 we have exterior of 150 so far and 360 - 150 = 210 left for exterior angles exterior with 127 interior = 53 exterior with 135 = 45 so 210 - 53 - 45 = 112 left for exteriors exterior with 173 = 180-...
August 5, 2014

typo ?
4000 meters / second maybe? Newton #2: Force = change in momentum / time (F= m a if m is constant but here it is not) change in momentum/second = [.050 kg * (4000 - 0) m/s]/second = 200 Newtons
August 5, 2014

History
The farmers got caught in a cycle of debt because it says they did not have capital to buy land and therefore I suspect they had to borrow.
August 5, 2014

physical
LOL !!! This is a trick question. You know the answer. It is exactly the same as throwing a ball straight up. It takes just as long to go up (0 = Vi - g t) so t = Vi/g h = Vi t - (1/2) g t^2 as it takes to go down 0 = h - (1/2) g t^2 = Vi t - (1/2) g t^2 - (1/2) g t^2 t = Vi...
August 5, 2014

English/ Help
Now what about A? Who misunderstood what? Did they think he was Darth Vader when he was actually Luke S? Now what about B? Was there milling around and people stepping on others' toes trying to get selfies and autographs? Now what about C? Who left. I might have but I was ...
August 5, 2014

English/ Help
http://www.jiskha.com/display.cgi?id=1407196486
August 5, 2014

English/ Help
Could swear I have seen this question before.
August 5, 2014

college physics
omega = initial omega + alpha * t if alpha is constant and it starts from rest t = omega/alpha
August 5, 2014

math
C = 9000 + 21 x yes Revenue = R = 49 x P = 49 x - 21 x - 9000 so P = 28 x - 9000 now for some reason they did not asdk how ma tires must be sold to break even but it would be P = 0 28 x = 9000 x = 9000/28
August 4, 2014

Algebra
Your notation is extremely awkward. We normally write x to a power as x^power like x^3 is x cubed Now I will do it your way but you have errors starting with the sign in the first line x(2x squared-x-3)+ 1(2x squared-x-3) should be x(2x squared-x-3) - 1(2x squared-x-3) then x*...
August 4, 2014

Algebra
again: http://www.jiskha.com/display.cgi?id=1407198511
August 4, 2014

Algebra
Did I not just do that ?
August 4, 2014

English/ Help
hmmmm ..... each pointed to their records of service and academic excellence.
August 4, 2014

Pre-College Algebra
distributive property: x * (2x^2 - x- 3) -1* (2x^2 - x- 3) = 2 x^3 - x^2 - 3 x - 2 x^2 + x + 3 combine like terms = 2 x^3 - 3 x^2 - 2 x + 3
August 4, 2014

math test review
h^2 + 64(2) = 18^2 = 324 h^2 = 196 h = 14 area = (1/2)(8sqrt 2)(14) =56 sqrt 2
August 4, 2014

Physics
You are welcome.
August 4, 2014

Physics
Stand on a scale and push on the ceiling :) Third law. Force by man up on bars --> force down on man Sum forces on the man who is not accelerating up or down m g down + handlebar force down force up on man = pedal force net force = 0 so no change of momentum (F = m a = 0) ...
August 4, 2014

English/ Help
I agree with you but I was a physics major :) C and D are just plain wrong. The car, not the fuel efficiency, is designed :)
August 4, 2014

math hw
all multiples of 6 are even and multiples of 3 Venn diagram (intersection is mult of 6) n are multiples of 6 22 - n are even only 15 - n are 3 only (22- n) + n + (15-n) = 30 37 - n = 30 n = 7
August 4, 2014

math hw
Hey (a^2-b^2)= (a+b)(a-b) remember forever (a+b)(a-b) = 20 2(a-b) = 20 a - b = 10
August 4, 2014

math
g = 2 b - 5 so yes, but they said b for boys
August 4, 2014

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