Friday
October 31, 2014

Posts by Damon


Total # Posts: 19,077

Physics for Technology
What is the momentum of a hammer of mass 0.8kg striking a nail at 5 m/s2? So, p = m v p = (0.8)(5 m/s) p = 4 kg-m/s note velocity is meters/seconds, acceleration is m/s^2 A nail stops the hammer in 0.08 seconds: what force is delivered to the nail? NEWTON #2 Force = rate of ...
September 6, 2014

Physics Help!!!!
going forward faster and faster going forward but the brakes are on going backward faster and faster going backward but the brakes are on
September 6, 2014

Teaching 4Grade Math
If you save 5% the first week you are down to 95% If you then save 5% of that the second week you are down to 95% of 95% = .9025 or at 90.25% of full charge which means you saved (1/2)(1-.9025)(100) = 4.875% per week on the average. That is hardly fourth grade. It is more in ...
September 6, 2014

Math
3/10 are boys 7/10 are girls total boys = x total girls = x+200 total students = 2x+200 (3/10)(2x+200) = x 6 x + 600 = 10 x 4 x = 600 x = 150
September 6, 2014

math 1 question
yes 2.5 times r = 2.5 r
September 6, 2014

Math
1.45 c = 79.95 c = 79.95/1.45
September 5, 2014

ALGEBRA
five and six is eleven (x+5)(x+6) seven - two (x-7)(x+2) I bet you mean 9x^2-16 which is difference of two squares a^2-b^2 = (a+b)(a-b) (3x+4)(3x-4)
September 5, 2014

Physics
v = Vi - 9.81 t 20 = Vi - 9.81 (2.1) solve for Vi then Use that Vi to get v at t = 4.7
September 5, 2014

physics
east components 2880 cos 42 = 2140 south components 2880 sin 42 + 4360 = 6287 magnitude = sqrt (2140^2+6287^2) tan (angle) = 6287/2140
September 5, 2014

Physics
I mean west is - x direction :)
September 5, 2014

Physics
West is - y direction Ax = -20.0km*sin(35.0º) NOTE NEGATIVE Ay = 1.650km or 20.0km*cos(35.0º)? Bx = 18.0km*cos(75.0º) By = 1.420km or 18.0km*sin(75.0º)? Rx = Ax + Bx Ry = Ay + By and Rz = 1.650 - 1.420 R = sqrt (Rx^2 + Ry^2 + Rz^2)
September 5, 2014

INTEGRAL CALCULUS PLEASE HELP!!!
I assume you mean the integrals or areas are 4 , 9 and 1 Sketch it all I can say is that the integral from 4 to 17 (not 9 to 17) is -12 because 4 + integral 4 to 17 + 9 = 1 I do not even know what 2) means. If it is integral F(x) dx - 4 intregral dx then answer above - (4(17...
September 5, 2014

Physics
On earth that 40 N weight would correspond to about m = W/g = 40/10 = 4 kilograms of mass which is around 8 pounds. This collie is actually a toy poodle. 200 kg ? That is about 450 pounds weight on earth which means the average patient stepped on the scale with her husband and...
September 5, 2014

Algebra
Just did, see below.
September 5, 2014

Physics
well, sure, but there is much more to it. As you stated the problem: x = (1/2) a t^2 so a = 2 x/t^2 or t = sqrt (2 x/a) but that is a gross oversimplification of what is going on with constant acceleration a if a = some constant acceleration v = Vi + a t where Vi is initial ...
September 5, 2014

math
hard to say
September 5, 2014

algebra
line of form y = m x + b m = (Y2/Y1)(X2-X1) = (4-0)/(2-1) = 4 check with other points (like (12-0)/(4-1) ) y = 4 x + b put a point in to find b 0 = 4(1) + b b = -4 so y = 4 x - 4
September 5, 2014

algebra
y = x (.658 - .000407 x) where is y = 0 ? at x = 0 and at x = .658/.000407 = 1617 ft long (that is part B) this is a parabola that crosses the x axis at 0 and 1617 so the vertex, max height, is halfway between at x = 808 what is the height? y = -.000407 (808^2) + .658(808) = ...
September 5, 2014

math 101
7.9 * sqrt 2
September 5, 2014

English
Does the second sentence not seem a bit strange? Does it need the word "ever" ?
September 5, 2014

math
5 3/12 - 3 10/12 is 4 15/12 - 3 10/12 is 1 5/12
September 5, 2014

Math PLease help
put in the form y = m x + b then m is the slope 3 y = -6 x + 12 2 y = -2 x + 4 y = -2 x + 4 y = -1 x + 2 -2 is not - 1 so not parallel -2 is not -1/-1 so not perpendicular
September 5, 2014

Math PLease help
6 x - 14 = 30 x + 54 + 28 assuming that = is a + 24 x = -96 x = -4
September 5, 2014

Physics
The first phase is easy if you have constant acceleration because the average speed until the stop is Vi/2 = 5 m/s t to stop = 148.3 / 5 = 29.7 seconds a = change in velocity/change in time = -10/29.7 = -.337 m/s^2 phase 2 displacement = 37.7 - 148.3 = -110.6 meters -110.6 = (...
September 4, 2014

Physics
because when the one that was fired upward gets down to cliff level it is traveling downward at the same initial speed down as the first one was.
September 4, 2014

Math
tan 72.5 = h/5
September 3, 2014

physics
Newton #2 - Force = rate of change of momentum so force * time = change in momentum (impulse) 100 * 5 = 25 * v
September 3, 2014

Homework
c = Q / [ w(T1-T2) ]
September 3, 2014

Algebra
6 * 2.8/4
September 2, 2014

math
9+21 = 30 456 is about 500 87 is about 100 about 30 thousand six hundred 30,600
September 2, 2014

social studies
Well, he failed to establish a permanent presence in North America and he and the other Vikings who followed him made enemies of the natives so that a permanent establishment probably would have required an army (or smallpox or measles to eliminate the locals). I am not sure ...
September 2, 2014

algebra
depends if your text includes zero as a natural number negative numbers are not natural numbers either 0 through 10 which is 11 or one through 10, which is ten
September 2, 2014

math
2 x + 4 y = 14 3 x - 4 y = 6 --------------- add 5 x = 20 x = 4 now go back and get y
September 2, 2014

math
These lines are the same. There are an infinite numbers of solutions, a y for every x you pick.
September 2, 2014

Math
70,016,090 32,000,232,000
September 2, 2014

Shurley English
That is an analogy. I did not say it was good analogy :)
September 2, 2014

Shurley English
a way something is like something else. Your arteries and veins are analogous to the water supply and wastewater piping system in your city :)
September 2, 2014

Algebra 2 Answer Check
You do not need me to operate the calculator Victoria :)
September 2, 2014

ratios
There are probably more cars than trucks, like 3/1
September 2, 2014

math
^%$*&@ math teachers think they are navigators. The "heading" is 215, NOT the "bearing". You take a bearing on something outside the ship, for example it might be the direction of a lighthouse. south is 180 so 35 degrees west of south answer = 145 cos 35
September 2, 2014

Algebra 2
sqrt 8100 = 90 ft baselines so 90 sqrt 2
September 2, 2014

Algebra 2
90/6 = 15 ft^2 each so the side of each square is sqrt 15 2 sqrt 15 + 3 sqrt 15 + 2 sqrt 15 + 3 sqrt 15 :)
September 2, 2014

Algebra 2 Answer Check
11 yes
September 2, 2014

Algebra 2 Answer Check
1. 2/√3 A: 2√3 / 3 yes 2. -18/√6 A: -3√6 yes Add or subtract. 3. 4√3 - 9√3 A: -5√3 yes 4. √8 - 15√2 A: -13√2 yes 5. √45 + √20 A: 5√5 yes 6. 2√48 + 2√12 = 2 sqrt (4*12) + 2 sqrt 12 = 4 ...
September 2, 2014

Algebra 2. HELP
You are welcome.
September 2, 2014

Algebra 2. HELP
I think you can graph straight line t = 0 to t = 8 (end of shift, you still have 18 left for the next shift :( n = 42 to n =18 -3(5) + 42 = 27
September 2, 2014

What is P?
1.05^3 = 1.157625 1.157625 * x = 8600 x = 7429.00
September 2, 2014

algebra
5 r </= 1 r </= 1/5 so what is the problem?
September 2, 2014

Math 2
56 = 2*2*2*7 96 = 2*2*2*12 7 rows of 8 and 12 rows of 8
September 2, 2014

Math
6, linear, 3 -6 = -3 7, V shaped, not linear -4+2 = -2 but |-2| = +2 8, certainly not linear, infinite (undefined) at x = 2 !!! You had to ask me that ???? 2 /(6-2) = 1/2 14, same sort of problem as 8
September 2, 2014

Math
if it has x^2 in it it is certainly NOT linear !!! f(1) = 1^2 + 1 - 2
September 2, 2014

Math
hey, y = m x + b is a straight line this is y = 1 x + 5 m = 1 b = 5 if x = -2 y = -2 + 5 = 3
September 2, 2014

Math
Huh? -2 + (-5/12) -3 5/12 + 1
September 2, 2014

calculus/physics
typo, 62 lbs/ft^3
September 2, 2014

calculus/physics
I do not know what y = x10 means Whatever the function is you must find the distance from the top (y =1) down to the centroid, which is the center of mass of the water. That is the distance you have to lift the water, call it h. Then find the volume V , the area times 2 feet. ...
September 2, 2014

phys urgent!
I do not have time to run your numbers but your approach is correct. constant Vx = 2.4*10^6 cos 38 so t = .015 /Vx Vyi = 2.4*10^6 sin 38 y = Vyi t -(1/2)(qE/m) t^2 = 0 at x axis
September 2, 2014

Algebra 2
ALWAYS !!!!!!!!!!!~!~!!!!
September 2, 2014

Algebra 2
http://www.mathsisfun.com/associative-commutative-distributive.html check out associative
September 2, 2014

chemistry. You did not ask a question
They both displace the same volume and mass of water so both weights are reduced by density of water * g * volume of cube
September 2, 2014

Algebra1
5 c = -30 c = -6
September 2, 2014

physics
v = (4/3) pi r^3 dv/dr = 4 pi r^2 (which is the surface area of course :) dv = 4 pi r^2 dr dv/v = 4 pi r^2 dr/(4/3)pir^3 dv/v = 3 dr/r here dr = .04 and r = .84 so 100 * 3 dr/r = 12/.84 = 14.3 %
September 2, 2014

Maths
x and (60-x) now in six years Tom = (x+6) brother = (54-x) (x+6) = 2 (54-x) x+6 = 108 -2x 3x = 102 x = 34
September 2, 2014

Finance
http://www.mortgagecalculator.org/ pmt = principal [ r/ {1 - (1+r)^-n} ] here principal = 150,000 r = interest rate / month = .08/12 =.006666666 n = 12 * 30 = 360 months I get 1100.65 per month that calculator link also says 1100.65
September 2, 2014

Maths,Physics,life science,geography,
I assume you mean Vi = 100 m/s and a = -5 m/s^2 v = Vi + a t 0 = 100 -5 t t = 20 seconds to go from 100 to 0 at -5m/s^2 d = Vi (20) - (1/2)(5)(20)^2 d = 100 (20) - 2.5(400) = 2000 - 1000 = 1000 meters to stop, runs 200 meters beyond the end of the runway into the harbor where ...
September 2, 2014

Math
You only have three sides, usual solution does not apply 2 w + L = 750 (note not 2 L) so L = 750 - 2 w A = w L = w (750-2w) -2w^2 + 750 w = A w^2 - 375 w = -A/2 w^2 - 375 w + (375/2)^2 = -A/2 + 35156 (w-375/2)^2 = -(1/2)(A -70,312) max at w = 375/2 = 188
September 2, 2014

math
length = x width = 2000/x 2x + 2 (2000/x) = 180 x + 2000/x = 90 x^2 + 2000 = 90 x x^2 - 90 x + 2000 = 0
September 2, 2014

Math
circumference of tire = pi D = 36 pi =113 inches/revolution 55 mi/h (1 h/60min)(5280ft/mi)(12 in/ft) = 58,080 inches/min 58080 inches/min (1 rev/113 in) = 514 rev/min 514 rev/min ( 2 pi radians/rev) = 3229 radians/min
September 2, 2014

Math, Calculus
what angle has a cosine = .49 ?? cos^-1 .49 = 60.66 degrees so our answers are 60.66 degrees above and below the negative y axis (180 deg) 180 - 60.66 = 119.34 degrees 180 + 60.66 = 240.66 degrees
September 2, 2014

Math
radius = 20 height of center = 25 height = 25 + 20 sin [2 pi t/4 - pi/2} I use 2 pi t/4 because that gives 0 at t = 0 and a full revolution, 2 pi, at t = 4. I put in the phase of -pi/2 so that at t = 0 we have 25 +20 sin -pi/2 = 25 - 20 = 5 meters, the starting point at t = 0...
September 2, 2014

Math
2 A = 87-63 = 24 so A = 12 degrees average = (87+63)/2 = 75 so D = 75 + 12 sin (2 pi t/24 - p) where p is the phase to give the right temp when t = 5 when t = 5 sin (2 pi 5/24 - p) = -1 or 5 pi/12 - p = -pi/2 p = 6 pi/12 + 5 pi/12 = 11 pi/12 so D = 75 + 12 sin ( pi t/12 - 11 ...
September 2, 2014

Math
sqrt (25+49) = sqrt 74
September 2, 2014

Physics, Math
Archimedes says: volume of fluid displaced * density of fluid * g = upward buoyant force = weight is neutrally buoyant mass = weight/g = volume*density 2500 * 1.225 = 3063 kg up now subtract the mass of air in the balloon 2500 * rho what is rho, the density of air inside at ...
September 2, 2014

chemistry
Block A has a greater mass in 125 cm^3 than Block B has in 145 cm^3 so Block A is more dense.
September 1, 2014

Physics
d volume/d h = base area (draw a picture :) dv/dt = dv/dh * dh/dt so dv/dt = base area * dh/dt let rho = m/v of candy d m = dv (rho) so dv = dm/rho so (1/rho) dm/dt = base area * dh/dt or dm/dt = rho * base area * dh/dt = (m/v) * L * W * dh/dt
September 1, 2014

calculus
passenger ship east = 16 t if t</= 2 then 16 t is the answer if t >2 cargo ship north = 12 (t-2) (t>2 :) d^2 = (16t)^2 + 144(t^2 -4 t + 4) d^2 = 256 t^2 + 144 t^2 -576 t + 576 d^2 = 400 t^2 -576 t + 576 d = sqrt (400 t^2 -576 t + 576) check, yes that is 32 miles at t...
September 1, 2014

physics
h = (1/2)(9.81)(tfall)^2 h = 330 (7.8-tfall) 660 (7.8-tfall) = 9.81 tfall^2 9.81 tf^2 + 660 tf - 5148 = 0 for the positive root I get 7.06 so the sound comes up for 7.8 - 7.06 = .7407 seconds .7404*330 = 244 meters
September 1, 2014

Math
LOL any percent of 100 is that percent ! 64% of 100 is 64 75% = .75 = (3/4) (3/4)(60) = 3*15 = 45
September 1, 2014

Please check my answers
Richard is renamed "member" after the verb In the second one, you is renamed "member" after the verb.
September 1, 2014

Math
4 /(1/2) multiply top and bottom by 2 8 /(2/2) or 8 ================ (1/4) /(1/3) multiply top and bottom by 3 (3/4) / (3/3) or 3/4 ========================= (15/4) / (1/3) again top and bottom by 3 45/4 = 11 1/4
September 1, 2014

Math
You are welcome. By the way, (I am curious) could you be the same person with the blue and white socks question? It is another subject (probability) entirely on another level.
September 1, 2014

Math
9*70 + 60 = 630+60 = 690 RIGHT !!! 60/70 = 6/7 = .8571428571 which is .86 to the nearest hundredth so 9.86
September 1, 2014

Check please
animals is DIRECT (gave animals, not people:) ZOOS is in a subordinate phrase as is TIME THEM is it all right :)
September 1, 2014

Engineering
for anything pointy with straight sides v = (1/3) area of base * height here 300 = (1/3)(pi r^2) h so r^2 h = 900/pi
September 1, 2014

Math
200 above -30 is 170 above zero. Draw it on a number line.
September 1, 2014

Math
You are welcome :)
September 1, 2014

Math
not quite that easy you start with 30 socks p first blue =6/30 p second blue = 5/29 so .2*5/29 product is p2 blue p first white = 24/30 p second white = 23/29 product is p 2 white so add .2*5/29 + 24*23/(29*30)
September 1, 2014

Math Proof
You are welcome.
September 1, 2014

Math Proof
The key word here is ** EVERY ** epsilon, including one vanishingly small .
September 1, 2014

Math Proof
You say that as epsilon ---> 0, |x-y|--->0
September 1, 2014

Math Proof
yes it has to be for any old epsilon, including one that is vanishingly small so that the difference between x and y is so tiny it does not exist.
September 1, 2014

Math Proof
well epsilon is anything you want it to be, but usually you make it a small number and let it approach zero. If x = 5 and y = 7 then |x-y| = epsilon now we would call epsilon = 2 BUT x is only equal to y if |x-y|< ANY epsilon bigger than zero, including e = .0000000001 so ...
September 1, 2014

Math Proof
on second thought draw x as a point on a number line, then y points epsilon to the right and to the left. Then let epsilon ---> 0
September 1, 2014

Math Proof
well, draw two points on a number line maybe a distance epsilon apart then let epsilon go to zero.
September 1, 2014

Math Proof
LOL, well I suppose one could prove it somehow. It seems to belabor the obvious though.
September 1, 2014

math
You are welcome.
September 1, 2014

math
.2 p = 700 p =3500 .8 p = 2800 That sure is an expensive pair of shoes !
September 1, 2014

physics
call one charge Q1 and call Q2 = (200*10^-6 - Q1)
September 1, 2014

physics
E is the electric field, the force on a point charge of ONE coulomb. You can do it with E for either charge, ten multiply by the charge on the other (the target) sphere. Normally though you would just use the Coulomb law form F = k Q12Q2/r^2 see: http://teacher.nsrl.rochester....
September 1, 2014

MAT222
I answered this below.
September 1, 2014

MAT222
equation 1 2 y = x - 2 equation 2 2 y = x - 2 or both are y = (1/2) x - 1 They are both the same line. ANY old x and y that fits one fits the other.
September 1, 2014

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