Tuesday
May 31, 2016

Posts by Damon

Total # Posts: 26,282

Physics
positive v from 0 to 2 negative v from 2 to 5 positive v from 5 to infinity parabola holds water, crosses below x axis between 2 and 5 vertex at t = 3.5
February 9, 2016

Physics
ans part 3 is from - 30 to + 2 = +32
February 9, 2016

Physics no part 4
part 4 use absolute value of distance is 52 + 20 = 72
February 9, 2016

Physics
I assume that we do not do negative time so v is positive for 0<t<2 and for t >5 when t = 0, x = -30 when t = 2, x = 22 when t = 4, x = 2 so 28 from 0 to 4 (part 3)agree part 4 +52-20 = 32
February 9, 2016

Physics
dx/dt = 6 t^2 - 42 t + 60 = 6 (t^2 - 7 t + 10) = 6 (t-2)(t-5) negative from 2 to 5 (Not 3 to 5)
February 9, 2016

Calculus
c = cups/day p = pennies/cup dc/dp = -2/5 so c = -(2/5) p + constant when p = 50, c = 40 so 40 = -2*50/5 + constant constant = 60 and c = -(2/5) p + 60 now you can make that p = 5n if you choose where n is an integer number of nickels c = -2 n + 60
February 8, 2016

physics
Now I did the grasshopper, same deal
February 8, 2016

physics
h = Vi t - 4.9 t^2 .587 = Vi t - .5*9.81 t^2 but t at top is Vi/9.81 where 0 = Vi - g t .587 = Vi^2/9.81 - .5 * 9.81 (Vi^2/9.81^2) .587 = .5 * Vi^2/9.81 Vi = 3.39 m/s vertical up Vi = speed * sin 58 so speed = 4.00 m/s part a u = 4.00 cos 58 = 2.12 m/s time in air = 2 * rise ...
February 8, 2016

Math
out of n, n-6 were gotten right so let's find n-6 Jack alone got 40 -32 = 8 Jill alone got 50-32 = 18 so in total alone they got 26 plus they got 32 together 26 + 32 = 58 right total plus the 6 wrong = 64
February 8, 2016

maths
every year multiply value by 0.90 1 year= 20,000 * .9 2 years 20,000 * .9^2 3 years 20,000 * .9^3 so part (c) n years 20,000 * .9^n It is like reverse compound interest, it will not go down 2,000 every year, but only 10% of its MOST RECENT value every year so 2 years 20,000...
February 8, 2016

History
Hey, that is pretty good. I am not a fan of his mother though.
February 8, 2016

physics
v at 10 m/s at t = 0 a = (final velocity-initial velocity)/time = (20 - 10)/5 = 2 m/s^2 so from (0,10) slope up = 2 m/s^2 to (5,20) from (5,20) to (25,20) horizontal from (25,20) to (35, 0 ) straight slope down (slope = -2)
February 8, 2016

physics
a = (final velocity -initial velocity)/time a = 49/16 m/s^2 weight = m g + m(49/16)
February 8, 2016

maths
looks like arithmetic sequence a = 3 d = 2 however sum of what terms?
February 8, 2016

Physics
now do A = F/m
February 8, 2016

Physics
Its acceleration will be in the direction of the net force Force horizontal component= Fh = 6.6*10^6 cos 47.5 Force vertical component = Fv = 6.6*10^6 sin 47.5 - 4.5*10^5*9.81 so Fh = 4.46*10^6 N Fv = 2.19*10^6 N F = sqrt(Fh^2+Fv^2) = 4.97*10^6 N tan A = Fv/Fh = 2.19/4.46
February 8, 2016

Science
eg: http://en.wikipedia.org/wiki/Lunar_mare
February 8, 2016

Science
1 a yes 2 b yes 3 a no b 4 c no d usually moon blocks sun light 5 a no c 6 d no b 7 a no c 8 b no a it all hits the other side 9 d no b 10 Google !!!! Hey - get yourself a light and a tennis ball and a soccer ball !
February 8, 2016

Math Questions
You are welcome.
February 8, 2016

Math Questions
2(9/3) = 2(3) = 6 yes 1 (18/6) = 1(3) = 3 yes 4 (10/5) = 4(2) = 8 yes
February 8, 2016

Math Questions
7(16/8) = 7(2) = 14 yes 6 (10/10) = 6(1) = 6 yes
February 8, 2016

Math
9.25% monthly .095/12 = .0079167 so every month multiply by 1.0079167 y = 1,000 (1.0079167)^(12x) now just activate your calculator :)
February 8, 2016

Maths
f(x,y) = 2 (x^2 + xy + 3 y + y^2) How could that be less than 0?
February 8, 2016

typos
Increases ?? from 15 m/s to 6 m/s ??? anyway a = (final velocity - initial velocity) / time d = Vi t + (1/2) a t^2 = 15 (20) + (1/2) a (400)
February 8, 2016

maths
a + (n-1) d second is a + d = 15 fifth is a + 4 d = 24 so a = 15 - d and (15-d) + 4 d = 24 3 d = 9 d = 3 then a = 12 so term n is 12 + (n-1)3
February 8, 2016

Math Please help me and fast
yes if you had 5 x = 0 for example, that would work for any old x and you would have infinite number of solutions. This is the opposite case.
February 8, 2016

Math Please help me and fast
0 x = 2 x = 2/0 undefined 4 y = 12 y = 3 b - 9 > 20 add 9 to both sides b > 29
February 8, 2016

Math
1. yes y = 100 (1/2)^(t/3) 2. looks good, divide by 2 every three days 3. I can not very well show you a graph maybe google graph exponential or graph A * B^-(kt) 4. 100 /(1/2)^3 = 100/(1/8) = 800 so yes but do not understand how you did it
February 8, 2016

Algebra
P = K D^2
February 8, 2016

Physics
F = k *stretch for each each supports 7.35 * 9.81/3 = 24 N 24 = k (.21) k = 115 N/m agree except you use 9.8 for g I suspect K = 3 k from part a = 343 omega = 2 pi f = sqrt(K/m) = 6.83 radians/s f = omega/2pi = 1.09 Hz T = 1/f = .919 seconds agree V = A omega sin (omega t) max...
February 8, 2016

social studies
My guess: The promises England had made to Palestinians.
February 8, 2016

Probability
Well, I guess about half of them 99,000 + 00,000 ? = 100,000 so I suppose about 50,000
February 8, 2016

Physics
a = (final velocity-initial velocity) / time a = (0 - Vi)/1.7 so a = -Vi/1.7 d = Vi t + (1/2) a t^2 50.7=Vi(1.7) -(1/2)(Vi/1.7)(1.7)^2 50.7 = (1/2)(1.7)Vi Vi = 59.6 m/s then a = - Vi/1.7 = -35.1 m/s^2 so F = m a = 13(-35.1) = - 456 N
February 8, 2016

physics
F1 horizontal T at 40 degrees from Vertical T cos 40 = m g T = 10 * 9.81 / cos 40 = 128 N F1 = T sin 40 = 128 sin 40 = 82.3 N
February 7, 2016

Physics
F on glider from spring = -kx beginning x = .1 meter potential energy in spring = kd^2/2 where d is extension = 5 d^2/2 = 2.5 d^2 = 2.5 (.1-x)^2 the potential energy at start = 2.5(.1)^2 = .025 Joules total the kinetic energy = (1/2)mv^2 = .1 (.2)^2 = .004 Joules so .025 = ....
February 7, 2016

physics
F = 1050 - 916 = 134 N UP a = F/m = 134/93.5 = 1.43 m/s^2 UP in other words his speed down is slowing
February 7, 2016

physics
I guess you mean maximum height of 100 m Vertical problem: Vi = 59 sin A v = Vi - 9.81 t at top v = 0 0 = Vi - 9.81 t so t = 59 sin A /9.81 at top 100 = Vi t - (9.81/2) t^2 100 = (59 sinA)^2/ 9.81 -(9.81/2) (59 sin a)^2/9.81^2 100 = (1/2)(59 sin A)^2/9.81 980*2 = (59 sin A)^2 ...
February 7, 2016

physics
We just need to do the vertical part of the problem. I assume it hit the ground where H = 0 Vi = 15 sin 35 = 8.6 m/s up H = Hi + Vi t - 4.9 t^2 0 = Hi + 8.6 (2.7) - 4.9 (2.7)^2 Hi = 12.5 meters
February 7, 2016

physics
You are welcome. I am sorry; I have no schedule (retired and doing a lot of other stuff).
February 7, 2016

physics
and tan angle = 22.2/16
February 7, 2016

physics
typo sqrt (22.2^2 + 16^2)
February 7, 2016

but the horizontal speed?
25 = 4.9 t^2 t = 2.26 seconds, yes v = Vi - 9.81 t v = -9.81(2.26) = -22.2 BUT WHAT ABOUT u ? 16 m/s horizontal speed = sqrt (22.2^2+16)^2 tan angle below horizontal = 16/22.2
February 7, 2016

math
n * (n-1) = 90 the rest cancels agree n^2 - n = 90 n^2 - n - 90 = 0 agree n = 10 or n = -9 agree 10 * 9 [ (n-2)! / (n-2)! ] = 90 for me all right
February 7, 2016

math
2 W + 2 (2 W + 3) = 66 6 W + 6 = 66 6 W = 60 etc
February 7, 2016

algebra
term 2 = a r term 4 = a r^3 term 5 = a r^4 term 1 = 1 term 3 = a r^2 ---------------------- ar (ar^3) = 2 (a r^4) a^2 r^4 = 2 a r^4 2 a = a^2 a^2 - 2 a = 0 a = 0 (won't work) or a = 2 now we need r I assume you mean the sum of the first 4 is 80 a + ar + ar^2 + a r^3 = 80 1...
February 7, 2016

Maths, Problem solving
x + x/4 +(x-90) = 180 2.25 x = 270 x = 120
February 7, 2016

Statistic
.75 and .83 .83 - .75 = .08 .08/.05 = 1.6 = z assuming your .05 is sigma and distribution normal http://davidmlane.com/hyperstat/z_table.html I get probability of .08 or above is about .05 I think the extra schooling helped
February 7, 2016

physics
That is really impossible to calculate. There is a change of momentum during the collision and force = change of momentum / duration of actual collision. That would be a fraction of a second but how long depends on the crushing characteristics of the body.
February 7, 2016

maths
90/90 - 28/90 = 62/90 = 31/45
February 7, 2016

physics (mechanics)
a = (20-15)/10 = 0.5 m/s^2 F = m a F = 1000 (0.5) + 270 F = 500 + 270 F = 770 N
February 7, 2016

math
combined speed = 110 110 mi/h * t = 660 t = 6 yes
February 6, 2016

Math
d = 4 q 10 d + 25 q = 390 10 (4q) + 25 q = 390 65 q = 390 q = 6 etc Your error is here: 0.40q+0.25q=3.90 then you said 65q=3.90 no 0.65 g = 3.90 3.90/0.65 = 6 not .06
February 6, 2016

pysics
Q = C m (T2-T1) = 400 (.5 kg) (116-16) note difference in deg K is the same as difference in deg C = 20,000 Joules
February 6, 2016

Math
34.375 / .125 = 275 I divided I do it the science way, multiply so units cancel you can do it by ratios .125 in/1 ft = 34.375 in / x ft .125 x = 34.375 x = 34.375 / .125
February 6, 2016

Math
34.375 in (1 ft/.125 in) = 275 ft
February 6, 2016

Math
That name game is just part of trying to hopelessly confuse me.
February 6, 2016

Math
LOL, talk about trying to confuse me ! If those are corresponding sides in two triangles and A is 4 times X then B is 4 times Y and m = 10/4 = 2.5 and C is 4 times Z and n = 16/4 = 4
February 6, 2016

Math
not without knowing the angles
February 6, 2016

Physics 30
Hey, just use Coulomb's Law F = k Q1 Q2 / d^2 if like charges, repel if opposite signs, attract see: http://en.wikipedia.org/wiki/Coulomb's_law
February 6, 2016

physics & math
sqrt ( 2*1.6*10) = 4 sqrt 2 = 5.66 m/s
February 6, 2016

typos
You mean g = - 32 ft/s^2 so h = Hi + Vi t + (1/2)a t^2 h = 105 - 9 t - 16 t^2 at ground: 0 = 105 - 9 t - 16 t^2 or 16 t^2 + 9 t - 105 = 0 t = [ -9 +/- sqrt(81+6720)]/32 t = [-9 +/- 82.5 ]/32 use positive time 2.30 seconds
February 5, 2016

Physics
V= i R 2 = .1 R and 2 = 5 R
February 4, 2016

Physics help
well electrostatic force causes hair to stand on end and gravity keeps the planets in orbit by the way
February 4, 2016

Physics PLEASE PLEASE HELP! CONFUSED
do vertical and horizontal problems separately Vertical Just plain fall, no initial velocity up or down so a) 10 = (1/2)(9.81) t^2 b) use that t to find out how far away he landed d = u t = 1.2 t c) vertical v = g t = 9.81 t horizontal u = 1.2 speed = sqrt (u^2+v^2) direction ...
February 3, 2016

physics
again that d is the part in the heavy liquid for the water depth use L-d
February 3, 2016

physics
B) rhoL L^2 d + rhoW L^2 (L-d) = rhoB L^3
February 3, 2016

physics
Force up on block = rhoL *L * L * d * g where d is the draft or distance submerged that has to equal the weight of the block which is rhoB L^3 g so rhoB L^3 g = rhoL L^2 d g d = (rhoB/rhoL) L d/L = rhoB/rhoL but we want (L-d)/L which is 1 - d/L 1 - d/L = fraction above = 1-...
February 3, 2016

True & False explanations Physics
When a projectile is fired at 45 deg. angle and is in free fall, the only point along the path that the acceleration of the object is zero is the instant when the object is at the highest point of its path. Answer: False Can someone explain how? ============================== ...
February 3, 2016

physics
v = Vi - g t v = 20 - 9.81(2) h = Vi t - 4.9 t^2 h = 20(2) - 4.9 (4)
February 3, 2016

One Last Queston
My vote is for A Nothing slows it down
February 2, 2016

differential equations
for purposes of integration n k m are constant then ds/dt = -ks (s^2/nm - S/n -s/m +1) = -k [ s^3/nm - s^2/n - s^2/m + s] =k[ -s^4/4nm +s^3/3n + s^3/3m -s^2/2 + c] You can play with this perhaps http://www.wolframalpha.com/input/?lk=3&i=plot++-s^4%2F4n+%2Bs^3%2F3n+%2B+s^3%2F3...
February 2, 2016

Physics
so weight = 4.11*9.81 = 40.3 N down Tension = 23.5 N up 23.5 - 40.3 = 4.11 a a = - 4.09 m/s^2 so a is down, weight wins
February 2, 2016

but what about the weight?
weight = m g = 4.11 * 9.81 Newtons
February 2, 2016

Math
V = pi r^2 h
February 2, 2016

maths
5/35 = x/21 x = 21 * 5 / 35
February 2, 2016

Algebra
I think you have typos but perhaps .75 x = 30
February 2, 2016

Algebra
in pennies: 4500 + 29.5 m = 9000 + 7 m 22.5 m = 4500 m = 200 miles
February 2, 2016

math
approximately 40828.19332
February 2, 2016

Math
56 * 4 = 224
February 2, 2016

US History
LOL - that was a media generated war ! It was the very origin of the term: "yellow journalism" starting with the explosion of the Battle ship Maine which seems to have been an engineering error but the press blamed on the Spanish. See: http://history.state.gov/...
February 2, 2016

Which war ?
Civil war? Vietnam ? Iraq?
February 2, 2016

algebra
100 a + 75 s = 14000 pennies a+s = 150 so a = 150-s 100(150 - s) + 75 s = 14000 15000 - 25 s = 14000 1000 = 25 s s = 40 then a = 150 - 40 = 110
February 2, 2016

algebra
2 x + 3 y = 252 4 x + 1 y = 244 multiply second equation by 3 2 x + 3 y = 252 12x + 3 y = 732 -----------------subtract - 10 x = - 480 x = 48 then y = 244-192 = 52
February 2, 2016

algebra
number = 10 x + y x+y = 12 y = 2 x so x + 2 x = 12 x = 4 then y = 8 so 48
February 2, 2016

algebra
f+4 = 3 (s+4) f-6 = 7(s-6)
February 2, 2016

math Chem formula wrong
3 % C 10 % Ca 87 % O Like no way CaCO3 40 + 12 + 48 = 100 molar mass 40% Ca, 12% C , 48% O so the real answer is 400 g , 120 g 480 g BUT using your strange numbers: in 100 grams: .03 * 100 = 3 g .1 * 100 = 10 g .87 * 100 = 87 g
February 2, 2016

Math
That is high precision. For low I would pick 3*10^3
February 1, 2016

Science
I guess they stick together. 8*10 - 6*50 = (6+8) v -220 = 14 v v = -15.7 m/s
February 1, 2016

Math
F = k x 10 = k (.5) k = 20 lb/in 15 = 20 x x = 0.75 in
January 31, 2016

mathematics
(6^5 /6^3) + 7^0 ??? 6^2 + 1 37
January 31, 2016

science
50 v = .1(50) v = .1 m/s
January 31, 2016

Science
Those are VECTORS You need BOTH magnitude and direction to add them. The resultant could have any magnitude between 20 and 70 meters
January 31, 2016

Science
r and Re F = G Mm/r^2 = (.25) G Mm/Re^2 or .25/Re^2 =1/r^2 .25 r^2 = Re^2 .5 r = Re r = 2 Re height = 2Re-Re = Re
January 31, 2016

physics
h = Hi + Vi t - 4.9 t^2 0 = 29 - 8.95 t - 4.9 t^2 t = [8.95+/-sqrt(8.95^2 + 4*29*4.9)]/(2*4.9) t = [8.95 +/-25.46 ] /9.81 use + t 3.51 seconds
January 31, 2016

physics
v = 19 - 9.81 t at top v = 0 t = 19/9.81 = 1.94 seconds to top at top h = 0 + 19 t - 4.9 t^2 h = 18.4 m high at top the same as the rise time 1.94 s the same 19 m/s but down now
January 31, 2016

physics
v = 0 = 81 - 5 t 800 = 81 t - 5.2 t^2 use that same stopping time t
January 31, 2016

physics
I guess we are to do this all in feet and seconds? v = 205 mi/h *5280ft/mi*(1h/3600s)) = 301 ft/s a = 301/2.7 = 111 ft/s^2 d = (1/2)(111)(2.7)^2 =406 ft
January 31, 2016

Physics
9.7*3 + 7.6*0 = 9.7 Va + 7.6 Vb so Va = (29.1 -7.6Vb)/9.7 then .5(9.7)(9)= .5(9.7)Va^2+.5(7.6)Vb^2
January 31, 2016

Physics
if acceleration is constant their average speed during the stop = 10/2 = 5 m/s 5 m/s * 30 s = 150 meters
January 30, 2016

math
21/x = 7/10 ? multiply both sides by 10 x 21 * (10 * x)/x = 7 * (10 * x)/10 210 = 7 x x = 210/7
January 30, 2016

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