Monday
January 16, 2017

Posts by Damon

Total # Posts: 28,769

math please explain!
this is because in feet and seconds acceleration of gravity, g = 32 ft/s^2 then velocity v = Vi - g t where Vi is initial velocity and g = 32 ft/s^2 and height h is h = Hi + Vi t - (1/2)g t^2 in this problem h = Hi + Vi t - 16 t^2 where Hi = 20 and Vi = 120
November 16, 2016

math please explain!
h = 20 + 120 * 3 - 16 (9) = 20 + 360 - 144 in feet where g = 32 ft/s^2
November 16, 2016

The Maths
multiply second equation by -1 then add +4x + 3y = -2 -4x + 4y = 16 ---------------add 0 + 7 y = 14 so = +2
November 16, 2016

Math
diameter = twice the radius
November 16, 2016

Science
v = Vi + a t v = 10 + 2.5 t 40 = 10 + 2.5 t t = 30/2.5 x = vi t + (1/2) a t^2 = 10 t + 1.25 t^2
November 16, 2016

Maths
weight of dog at time t how much weight the dog gained between those times
November 16, 2016

Math
60/4 = 15
November 16, 2016

Calc
well the integral is x^4/4 + C Now in between x = 0 and x = 3 the slope of the integral must be f(0) = 0 f(3) = 27 so the integral must be between 0 + 0(3) = 0 or 0 + 27*3 = 81 In fact the integral is 3^4/4 = 81/4 or about 20
November 16, 2016

science
v = Vi + a t v = 0 + 2 (3.2) = 6.4 m/s
November 16, 2016

Math
(x+25)/2 = 3 x
November 15, 2016

Science
Flat , perpendicular hard walls, ceilings and floors are a no-no. Use heavy carpets, hanging heavy fabric, and soft ceiling tile. Break up the flat perpendicular surfaces with nooks and crannies and odd angles and big furniture. Use soft seating in an auditorium. You can get ...
November 15, 2016

Chem
.065 = .15 x + .01 .15 x = .055 x = 5.5/15
November 15, 2016

geography
I am inclined to say Google it but you get a barrage of propaganda. With the Balfour Declaration the English opened the eastern coast of the Mediterranean Sea to settlement by Jewish immigrants. That was kind of them but ignored the fact that people, namely Palestinians, ...
November 15, 2016

Algebra2
You are welcome.
November 15, 2016

Algebra2
(x+1)(x-3)(x-3) = 0 Three real roots single real at x = -1 double real at x = 3 http://www.wolframalpha.com/input/?i=solve+x%5E3+-5x%5E2+%2B+3x+%2B+9+%3D+0+%3D+0
November 15, 2016

algebra
one worker paints 400 meters in 5 hours so one worker does 80 meters/hour 80 m/wh * 4 w * 2 h = 640 m
November 15, 2016

Math
a^2 + b^2 = 36 a + b + 6 = 14 so a = 8-b 64 - 16 b + 2 b^2 =36 2 b^2 - 16 b + 28 = 0 b^2 - 8 b + 14 = 0 b = [ 8 +/- sqrt (64 -56) ]/2 b = [ 8 +/- 2sqrt 2 ]/2 b = 4+/-sqrt 2 if b = 4+sqrt 2 a = 4 - sqrt 2 A = (1/2)ab = (1/2)(16-2) = 7 m^2
November 15, 2016

math
b + 2 b = 1500 3 b = 1500 b = 500
November 15, 2016

math
14.0 - 6.7 = 7.3
November 15, 2016

physics think typo in speed
v = Vi + a t 12.5 = 226 + a t so a = - 213.5/t d = Vi t + .5 a t^2 105 = 226 t - .5 * 213/t * t^2 105 = 226 t - 106.5 t t = .879 seconds a = -213/.879 = -242 m/s^2 you can do the rest but suspect you have a typo
November 15, 2016

physics
conservation of momentum in N/S and in E/W directions. Initial momentum is zero.
November 14, 2016

Hey, one is enough
I already did one like this below.
November 14, 2016

physics
total mass = .14 +.47 = .61 kg weight = .61*9.81 friction force = .5 * .61 * 9.81 work done = force * distance = .5*.61*9.81*6.8 so (1/2)(.61) v^2 = .5 * .61 * 9.81*6.8 where v is initial speed of can with pellet v^2 = 9.81*6.8 solve for v now conservation of momentum u is ...
November 14, 2016

physics
get speeds from conservation of momentum 93 g = 60 v 15 g + v t = 83 15 g = 83/2 --------------- so -------------- g = 83/30 = 2.77 v = 93/60 *83/30 = 4.29 v t = 41.5 t = 9.67 seconds check 9.67 * 4.29 = 41.5 15 * 2.77 = 41.55 v/g = 4.29/2.77 = 1.55 93/60 = 1.55 ok
November 14, 2016

Science
v = Vi - g t = 15 - 9.81 (.5) = 10.1 m/s h = Vi t - 4.9 t^2 = 15 (.5) -4.9(.25)
November 14, 2016

Physics
3.70 v + 4.70 (8) = (3.7+4.7)(15.6)
November 14, 2016

I do not know
If you fired it straight up, the truck would not move. If you fired it straight back and there were no brakes on the truck then 53.8 (41.7) = (856-53.8) v
November 14, 2016

physics
86 * 2.9 - 18 * 1.4 = (86+18)v
November 14, 2016

algebra
.03(x)+ .04(10,000-x) = 320
November 14, 2016

Math
agree 8/52 = 2/13 agree 4/52 = 1/13
November 14, 2016

Maths
z = 1000 - .01 x^2 - .02 y^2 dz = -.02 x dx -.04 y dy dz= -.02(60)dx - .04(1000)dy dz = -1.2 dx - 40 dy move in y direction , about 40 times as effective as x motion dz/dy = -40
November 14, 2016

physics
dv/dx = 6/4 = 1.5 m/s^2
November 13, 2016

Physics
ah, 160 cm = 63 inches 63 - 36 = 27 inch fall = 2.25 feet down fall so how fast did it leave hand moving horizontally at t = 0? m g h = (1/2) m u^2 u = sqrt (2 g h) u = sqrt (2 * 32 * 2.25) u = 12 feet/second horizontal speed That will not change until we hit the pins if ever ...
November 13, 2016

Physics
of course all shorter ranges have a lob angle and a straight shot angle :)
November 13, 2016

Physics
That is maximum range, no other angle will reach that range.
November 13, 2016

Calculus
oh, you want the derivative of the inverse function x = (y+9)/(y+3) dx = [(y+3)dy - (y+9)dy]/(y+3)^2 dx = -6 dy/(y+3)^2 dy/dx = (y+3)^2/-6
November 13, 2016

Calculus
did not see you wanted derivative either x = y^3 + 8 y - 3 dx = 3 y^2 dy + 8 dy dy/dx = 1/[3 y^2 + 8] if y = 6 1/[116]
November 13, 2016

Calculus
Sorry
November 13, 2016

Calculus
Do you mean f(x) = x^2 + 8 x - 3 ?? then to find f'-1 x = y^2 + 8 y -3 put in x = 6 y^2 + 8 y - 9 = 0 (y-1)(y+9) = 0 y = 1 or -9
November 13, 2016

Calculus
integral p dx of 88650 dx (3x+396)^-1 let z = 3x+396 then dz = 3 dx and I have 88650 (dz/3)/z or 29550 dz/z = 29550 ln z if x = 40, z = 120+396 = 516 if x = 50, z = 150+396 = 546 so 29550 [ln 546 - ln 516] = 29550 (.0565) = 1670 divide by 50-40 = 10 p average = 167...
November 13, 2016

Physics
d = (1/2) a t^2 = 45.6 You know a, solve for t v = a t
November 13, 2016

Civic Education
LOL - as long as the private parties are not "super delegates".
November 13, 2016

Math
h1 = 6 + 5 t h2 = 51 - 2 t when is h1 = h2 ? 6 + 5 t = 51 - 2 t 7 t = 45 t = 6 3/7 seconds
November 13, 2016

math
multiply everything by 4 4 * 2/3 = 8/3 = 2 2/3
November 13, 2016

Science
P = i V 60 = i (120) i = .5 amps V = i R R =120/.5 = 240 Ohms or P = V^2/R so R = 120^2/60 = 240 Ohms
November 13, 2016

math
Because it tells you how unpredictable a given sample might be. If you look at ages of children the average might be 10. If they are all in grade five they might all be pretty close to five. However if they are in classes from kindergarten to high school sophmores they might ...
November 13, 2016

Physics C: Mechanics
12 pi = (1/2) alpha (1.2)^2 so solve for alpha a = acceleration down of mass = r alpha = .05 alpha so 1 g - T = 1 a T = 1(g-a) Torque = .05 T = I alpha solve for I
November 13, 2016

Physics C: Mechanics
hollow cylinder I = m r^2 m a = m g sin A - torque/r m a = m g sin A - m r^2 alpha /r a = g sin alpha - r alpha but r alpha = a so a = (1/2) g sin A --------------------------------- solid sphere I = (2/5) m r^2 force down = m g sin A again force up * r = I alpha ma = m g sin ...
November 13, 2016

Math (Algebra)
then a = (60-b) .2(60-b) + .4 b = 18 12 - .2 b + .4 b = 18 .2 b = 6 b = 30 a = 30
November 12, 2016

Math (Algebra)
You are seriously right in your equations.
November 12, 2016

Physics
Ke at start = .5 (.125) 28^2 = 49 Joules .7 * 49 = 34.3 Joules = m g h = .125 * 9.81 * h so h = 28 meters
November 12, 2016

Math
n boys and n girls so 2 n total 3 n/5 + n/2 did not go that is 6 n/10 + 5 n/10 = 11 n/10 did not go 11 n/10 / 2n = (11/20) did not go
November 12, 2016

Math
80/6 = 13.3 so say she buys 13 * 5 = 65 then she gets 65/5 = 13 free which is 78 so she needs to buy 2 more 65 + 2 = 67
November 12, 2016

L'Hospital's Rule and Indeterminate Forms
Hmmm, as far as I know it applies only to 0/0
November 12, 2016

Math
patience, patience , plug and chug
November 12, 2016

Math
n marbles n/3 ---> Alvin 2 n /3 ---> J and S (5/8)(2n/3) ---> J so (3/8)(2n/3) ----> S which is (1/4)n
November 12, 2016

Math
y = 44.82 + .55 x In other words none of the above
November 12, 2016

math
2 n/3 + 72 = 1.20 n 2 n + 216 = 3.6 n 1.6 n = 216 n = 135 1*3*5 = 15
November 12, 2016

Chemistry
2HCl + Ca(OH)2 ---> 2 H2O .8 liters *.3 mol/liter = .24 mol Ca(OH)2 so we need .48 mols HCl .48 mol * 1000 ml/2 mol = 240 mL
November 12, 2016

Chemistry
1/3 cup = 145/3 = 48.3 kcal 48.3 kcal * 60 min/195 kcal = 14.8 minutes
November 12, 2016

Maths
You are welcome.
November 12, 2016

Wicked hard :)
even for a contest.
November 12, 2016

Maths
sum for the 7 over 10 must be divisible by 7 and from 77 to 140 by sevens 77, 84 , ...... 105 , 112 ..... 140 that sum + 2*8+9 or 25 must be divisible by 10 LOL 105 !!! 105 + 25 = 130 130/10 = 13
November 12, 2016

Math
Class 4—Greater than 6350 kg. to 7257 kg. (14,001–16,000 lbs.) If you increase the weight of a 14,000 pound truck by 4,000 pounds it will be MORE THAN 16,000 pounds
November 12, 2016

Math
[(x-24)/2 ] after Keri [(x-24)/4 ] after firemen [(x-24)/4 ] (1/3) after policeman = 7 so [(x-24)/4 ] = 21 (x-24) = 84 x = 108 ================ ================ check (108 - 24 /4 = 21 * 1/3 = 7 sure enough
November 12, 2016

Math
75/105 I think.
November 12, 2016

typo ?
Maybe you mean A(t) = 500 e^-(.044 t) ???????? A(20) = 500 e^-.88 = 500 * .415
November 12, 2016

physics
power in watts = energy in Joules / time in seconds
November 12, 2016

PHYSICS
I thought internal energy was usually called U Q is like heat flowing into a pot from the flame beneath W is like a piston moving and pushing a connecting rod U is like the water in the pot turning from cold to hot, storing energy provided by the flame beneath
November 12, 2016

Physics
for starters: gasoline engine burning generates heat, which radiates off into space from the surface of the engine and in the exhaust gasses. That is part of the efficiency of the thermodynamic cycle in the piston cylinders friction in bearings, gearing, crankshaft/bearings ...
November 12, 2016

physics
Yes, the air drag on the rain drop equals the gravitational force at fairly low speed. The important thing is: Force down = constant*volume Force up = constant * area so force down/force up = constant* L^3/L^2 = constant times length measurement for bodies of similar geometry ...
November 12, 2016

Trigonometry
3,4,5 right triangle sin T = 3/5 cos T = 4/5 tan T = 3/4
November 12, 2016

Linear Algebra
Yes because you can make V3 out of a linear combination of V1 and V2 V3=-3V1+2V2 that means that all three lie in a two dimensional plane. We could express all three as a linear combination of two orthogonal vectors in that plane.
November 12, 2016

math
p = pigs p + c = 61 c = 5 + 3 p c = (p/2)7 - 2 ====================== 2 c = 7 p - 4 2 c = 10 + 6 p so 7 p - 4 = 10 + 6 p p = 14 c = 47 h = 2 =============== check total = 63
November 12, 2016

You do some
Hey, I am not going to do all your work for you. This is the same idea as the one I did.
November 12, 2016

chemistry
.03 / 4 = .0075 mols of KNO3 needed .0075 * 101 g/mol = .758 grams
November 12, 2016

Math
4.6875 buses are needed but that does not work out very well, so we will need between 4 and 5 which means five if we are to take everyone because four buses only hold 4*32 = 128 people However five buses hold 5*32 = 160 so we will have 160 - 150 = ten seats empty
November 12, 2016

physics
from left end moments 5*200 + 500*10 + 80*2 = total load * cg from left total = 200 +300 + 500 + 80 = 1080 1080 x = 6160 x = 5.7 m
November 12, 2016

Physics
Why are you using conservation of energy? It is going up in smoke here. Use F=m a. average speed during stop = (7+0)/2 = 3.5 m/s so time to stop = 1.5 / 3.5 = .4286 seconds v = Vi + a t 0 = 7 +a(.4286) a = -16.3333 m/s^2 same force in second case, same mass so same ...
November 12, 2016

Math
h^2 + d^2 = 22^2 h/d = 4 or less 16 d^2 + d^2 = 22^2 17 d^2 = 22^2 d = 5.336 then h is limited to 4 d = 21.3 feet
November 11, 2016

calculus
y = f(e^t/(e^t+1)) dy/dt = dy/dx * dx/dt chain rule = dy/dx * d /dt [ e^t/(e^t+1) ] = dy/dx [ (e^t+1)e^t - e^2t ]/(e^t+1)^2 now what is x(1-x) ? [e^t/(e^t+1)][1-e^t/(e^t+1)] = [ e^t(e^t+1)- e^2t]/(e^t+1)^2 The same !!!
November 11, 2016

Physics - Buoyant Force Question
:) I just Googled: murdered by roman soldier on beach in Sicily and it worked immediately:)
November 11, 2016

Physics - Buoyant Force Question
Hint - He was murdered by a Roman soldier on a beach on his home island of Sicily.
November 11, 2016

no way
Some of these are very easy. What are your answers?
November 11, 2016

Ms sue plz help
http://study.com/academy/lesson/hamilton-and-the-federalists-vs-jefferson-and-the-republicans.html
November 11, 2016

Physics
Resistance is cut to 1/4 of original HOWEVER resistivity is a function of material. It does not change with geometry so (c) remains the same. http://hyperphysics.phy-astr.gsu.edu/hbase/electric/resis.html
November 11, 2016

social studies help!!
no
November 11, 2016

Nonsense
A. Use one name and type question once. B. Type entire question. Kinetic energy where? when? Potential energy is m g h so you can find h, the cliff height, easily. You could therefore find the kinetic energy at the bottom due to falling easily. However you have no idea what ...
November 11, 2016

More needed
A = 1000 if t is years after 2016 however without knowing a, can not do.
November 11, 2016

Calculus
can 3-t = t/2 ? only if 1.5 t = 3 t = 2 now when t = 2 2 + 2*2 = 2 + 3*2 whoops, no way
November 11, 2016

Calculus
red: xr = 3 - t yr = 2 + 2 t zr = 6 + 2 t black: xb = t/2 yb = 2 + 3 t zb = 2 + t at t = 0 xb - xr = -3 yb - yr - 2-2 = 0 zb - zr = 2-6 = -4 so d = sqrt(9+16) = 5 answer part a)
November 11, 2016

Physics
quick check using 10 for g 8 = 20 - heat heat is about 12
November 10, 2016

Math, Precalc
A bearing by the way is the direction of something from you. For example that lighthouse bears 10 degrees off our starboard bow or 27 degrees magnetic. The direction you point the fishing boat is heading.
November 10, 2016

Math, Precalc
Oh the time = 14.2/2 = 7.1 hours
November 10, 2016

AAARRRGGGHHH
A fishing boat leaves port at 4 KNOTS at a HEADING of 80? for 3 hours, then turns to a HEADING of 0? at 3 KNOTS for 4 hours, and finally changes to a HEADING of 200? at 6 KNOTS for 5 hours. At this point, the boat heads directly back to port at a speed of 2 KNOTS. Find the ...
November 10, 2016

pre-calculus
(3x+9)(x+3)/ [(x-5)(x+2)] in the numerator I used 3x+9 instead of x+3 so that as x goes to infinity the fraction goes to 3x^2 + little stuff /x^2 + little stuff ---> 3
November 10, 2016

no equal sign, no parenthese
I have no idea what is numerator and what is denominator and you can not solve an expression.
November 9, 2016

Physics
U = hor speed = 30 cos 60 = 15 Vi - initial ver speed = 30 sin 60 = 26 get time upward v + Vi - 9.81 t 0 = 26 - 9.81 t at top t = 26/9.81 that is half total time range = 2 * 15 * 26/9.81
November 9, 2016

Hey, scroll down
I just did this
November 9, 2016

MATH - PLEASE HELP!!
L = 2 w - 3 and L w = 65 so L = 65/w 65/w = 2 w - 3 65 = 2 w^2 - 3 w 2 w^2 - 3w - 65 = 0 (w+5))(2w-13) positive w = 13/2 = 6.5 etc
November 9, 2016

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