Wednesday

August 5, 2015

August 5, 2015

Total # Posts: 21,627

**science**

weight * tan 4 = m a m g tan 4 = m a a = g tan 4
*July 5, 2015*

**maths**

LOL, should have checked that !
*July 5, 2015*

**maths**

We know that (x-sqrt 2) is a factor 6 x^3 + 2 x^2 - 10 x -4 sqrt 2 = 0 (x-sqrt 2)( a x^2 + b x + c) = 0 well, c better be 4 (x-sqrt 2)(a x^2 + b x + 4) = 0 now I will use distributive property to split this up x (a x^2 + b x + 4) -sqrt 2 (a x^2 + b x + 4) = 0 x terms: 4 x - b ...
*July 5, 2015*

**Math**

The first roll has no effect what so ever on the results of the second roll. They are independent events. Dependent events are those where the first outcome has an effect on the second. For example if you have two green balls and two red balls in a hat. The probability of ...
*July 5, 2015*

**physics**

There is no such thing as a force of 2 kg, sorry
*July 5, 2015*

**Math**

x^2 = t^2 cos^2 y^2 = t^2 sin^2 x^2 + y^2 = t^2(cos^2+sin^2) = t^2 but t^2 = z^2 so x^2+y^2 = z^2
*July 5, 2015*

**math**

36 + .2(450-100) assuming one day
*July 4, 2015*

**physics**

oh max acceleration magnitude = A w^2 = 5.6*10^-7 * (5040)^2
*July 4, 2015*

**physics**

harmonic motion with w = 2 pi *frequency or 2 pi/period y = A sin w t dy/dt = v = A w cos w t d^2y/dt^2 = a = -A w^2 sin wt = -w^2 y here v max = Aw = 2.82*10^-3 and A = 5.6*10^-7 so w = 2 pi f = 2 pi/T = 2.82/5.6 * 10^4 = .504*10^4 = 5040 radians/s f = 5040/2pi = 801 Hz T = 1...
*July 4, 2015*

**physics**

You are welcome.
*July 4, 2015*

**physics**

F = k x k = 82/.0191 F = (82/.0191) * .0520
*July 4, 2015*

**phys**

(I wonder if whoever gave you this problem really thought out the implications of the landing :)
*July 4, 2015*

**phys**

h = Hi + Vi t - 4.9 t^2 assume the road was level so Vi = 0 1.5 = 20.2 + 0 - 4.9 t^2 4.9 t^2 = 18.7 t = 1.95 seconds in the air to fall 18.7 meters so how far did he go horizontal in those 1.95 seconds? d = u t 60 = u * 1.95 u = 30.7 meters/second horizontal for the whole jump...
*July 4, 2015*

**science 207 lab wk 5**

How on earth would we know what is in wk 5 of science 207? We are not at your school or perhaps even in your country.
*July 4, 2015*

**Science**

4.9 t^2
*July 4, 2015*

**Science Help Not sure**

Ui = initial speed = 126*10^3/3600 = 35 m/s 65-126 = -61*10^3 meters / 3600 seconds = -16.94 m/s speed change -16.94/8 = -2.12 m/s^2 acceleration d = Ui t - (1/2) a t^2 = 35*8 -(1/2)(2.12)(64) = 212 m so A
*July 4, 2015*

**Science**

v = a t hey, try some of these yourself !
*July 4, 2015*

**Physics**

Vi up = 15 sin 30 = 7.5 m/s initially u = 15 cos 30 = 13 m/s forever Hi = 40 then h = Hi + Vi t - 4.9 t^2 0 = 40 + 7.5 t - 4.9 t^2 or 4.9 t^2 - 7.5 t - 40 = 0 t = [ 7.5 +/- sqrt(56.25 + 784) ] / 9.8 use + root of course t = 3.72 seconds then v = Vi - 9.8 t = 7.5-36.5 = -29 m/s...
*July 4, 2015*

**physics**

3 sin thete = 2 theta = 41.81 V across = 3 cos theta = 2.24 mi/hr (1/4)/2.24 = .112 hr = 6.7 minutes He has zero velocity parallel to the shore (that is the whole point) However he has speed of 2.24 mi/hr perpendicular to the shore.
*July 4, 2015*

**Physics**

well, I suppose they both have the same acceleration, call it a The total mass is 5000 kg The total force on the system is 6000 N so a = 6000/5000 = (6/5) m/s^2 Now how much of that is on the truck? F = 3000 a = 3000 (6/5) = 3600 Newtons from the car on the truck so the force ...
*July 3, 2015*

**physics**

All yo can really find in this world is DIFFERENCES in potential energy. In this case, whoever wrote the question probably expected you to define zero potential at the FLOOR so the h you use for part 1 which is 6.5 -2.5 = 4 is NOT the h you use for part 2 for part 2, use the ...
*July 3, 2015*

**physics**

LOL, it takes time, it is almost midnight, and I have to work tomorrow.
*July 2, 2015*

**physics**

v = omega r 1. 6.12 * 2.20 = 13.464 m/s 2. 6.12 * 15.2 = 93.024 3. 6.12 * 3.15 = 19.278 (1/2) m v^2 1. .5 * 6.36 * 13.464^2 = 577 Joules 2. you can do the next two 3. add them I = m r^2 1. 6.36 (2.2)^2 = 30.8 2. you can do 3. you can do add them for total I Ke = (1/2) I omega^...
*July 2, 2015*

**physics**

There are only two horizontal forces in this problem, at the wall and at the ground. Therefore they are equal and opposite, call the magnitude F now balance vertical forces 886 + 350 = force down = 1236 N that is therefore the normal force up at the ladder base the max ...
*July 2, 2015*

**math**

4 = 2^2 so (2^2)^(x+2) = 2^x but (a^b)^c = a^(bc) so 2^(2x+4) = 2^x 2x+4 = x x = -4
*July 2, 2015*

**math**

Now you can solve what I gave you for x which is the pounds of nuts with cashews.
*July 2, 2015*

**math**

5 t^2 - 7 t - 1 = 0 t = [ 7 +/- sqrt(49+20) ]/ 10 t = [ 7 +/- sqrt(69) ] / 10
*July 2, 2015*

**math**

3.95 x + 1.15 = 1.70 3.95 x = .55 x = .139 yes then .5 - x = .361 ------------------ check 6.25 * .139 = .869 2.30 * .361 = .830 ------------------- add ****** .5 lbs = 1.699 or in other words 1.70
*July 2, 2015*

**math**

x with cashews costs 6.25 x (.5-x) with peanuts costs 2.30 (.5-x) so 6.25 x + 2.30(.5-x) = 1.70
*July 2, 2015*

**Math**

if she works 40 hours per week (we are just guessing that), then she worked 80 hours for $383 383/80 = $4.7875 per hour
*July 2, 2015*

**Math**

The y intercept is where the line hits the y axis, in other words when x = 0 that means that in the equation of the line y = m x + b the y intercept is where x = 0 and y = b saying a point is on -3 and the other on + 5 does not help me You have to say for example at one point ...
*July 2, 2015*

**Finite**

maximize p = 8x + 10y subject to .6x + .45y <= 400 .4x + .55y <= 300 =============================== Vertex Lines Through Vertex Value of Objective (566.666667,133.333333) .6x+.45y = 400; .4x+.55y = 300 5866.666667 Maximum (666.666667,0) .6x+.45y = 400; y = 0 5333.333333...
*July 2, 2015*

**Finite**

http://www.zweigmedia.com/RealWorld/LPGrapher/lpg.html
*July 2, 2015*

**Finite**

cc = .6 x + .45 y </= 400 rb = .4 x + .55 y </= 300 income = i = 8 x + 10 y objective, maximize graph those functions, check the corners
*July 2, 2015*

**Finite Math**

well, in that first column I would like to see 1 0 0 so I would multiply row 1 by 2 subtract the result from row two and put that result where row 2 is then I would multiply row 1 by 3 instead of by 2 and subtract the result from row three, placing the result in row three.
*July 2, 2015*

**Applied Mathematics ( Mechanices**

a ) m g b ) m(g+5) c ) m(g-5) on earth g is about 9.81 m/s^2
*July 2, 2015*

**physics**

the braking force is opposite to the direction of motion, so we are doing negative work on the train delta W is negative Are we putting heat into the train? I think not. In fact heat is going out into the air as the brakes heat up. delta Q is negative So I suspect that the ...
*July 2, 2015*

**mathematics**

0.400 * 6.00 = $2.40
*July 2, 2015*

**Physics**

a = dv/dt = 4 i + 14 t F = m a 40 = 4.6 sqrt (4^2 + 14^2 t^2) (40/4.6)^2 = 16 + 196 t^2 solve for t use that t to get v and a Then v dot a = |v||a| cos theta
*July 2, 2015*

**Physics**

tension T force F horizontal vertical: T cos 32.9 = m g horizontal: T sin 32.9 = F
*July 2, 2015*

**algebra**

or ln (2-x) = 14 e^{ln(2-x) = 2-x so 2-x = e^14 x = 2 - e^14 x = - 1202602
*July 1, 2015*

**Differential Equation**

hmmm, not sure but dy/dx = [(1-y^2)/(1-x^2) ]^.5 dy/(1-y^2)^.5 = dx/(1-x^2)^.5 let y = sin p let x = sin r dy = cos p dp and dx = cos r dr cos p dp/cos p = cos r dr/cos r dp = dr
*July 1, 2015*

**Basic electrical engineering**

electron charge = e in coulombs i = how many coulombs pass a point in a second 65.5 coulombs/second = e * electrons per unit volume * area *length they move in one second which is .0153 inched I think I need the density of electrons in electrons per cubic inch
*July 1, 2015*

**Math**

8 a + 8.0 c = 72 8 a + 4.5 c = 58 ----------------- subtract 3.5 c = 14 c = 4 so a = 5
*July 1, 2015*

**Calculus Derivative**

let z = x^x y = e^z dy/dz = z e^z = x^x (e^x^x) dy/dx = dy/dz * dz/dx so we need dz/dx when z = x^x look here http://www.analyzemath.com/calculus/Differentiation/first_derivative.html for dz/dx = (ln x + 1) x^x so x^x ( e^x^x) (ln x + 1) x^x =x^2x e^x^x (ln x + 1)
*July 1, 2015*

**Algebra 1**

.08*12 + .20*x = .16 (12+x)
*July 1, 2015*

**Chem 105**

P1V1/T1 = P2V2/T2 750 * 36 /(273+10) = P2 * 15 /(273+78)
*July 1, 2015*

**Math**

10!/12! = 1/(12*11) 7!/5! = 7*6 7*6 /(12*11) = 7/22
*July 1, 2015*

**calc**

We agree, if that is indeed the question :)
*July 1, 2015*

**calc Huh??**

do you mean product of x and y? dy/dx = 8 x y or do you mean dy/dx = 8 x / y or what ? if the latter then y dy = 8 x dx y^2/2 = 8 x^2/2 + C y^2 - 8 x^2 = constant
*July 1, 2015*

**Geography**

In fact, just Angles, Saxons, Danes and Norse including former Vikings from Normandy in France are worth a few books covering their effect on culture and settlement of England :) Are you writing a PhD dissertation ?
*July 1, 2015*

**Geography**

This question is out of control !!! I do not know where to start. Perhaps divide up into regions of Europe: 1. Eastern Med and Black Sea - Greece, Balkans 2. Western Med - Italy(Etruscan, Roman), French Med coast, Spain 3. Atlantic coast, southern - Portugal, Basques, Frence, ...
*July 1, 2015*

**algebra**

10 * 2^(4 x - 5) = 41 ? 2^(4 x - 5) = 4.1 agree ln 2^(4 x - 5) = (4x-5) ln 2 = ln 4.1 agree 4 x - 5 = ln 4.1 / ln 2 = 2.036 4 x = 7.036 x = 1.76
*July 1, 2015*

**Maths**

(x+11)(x+8) = 208 x^2 + 19 x + 88 = 208 x^2 + 19 x - 120 = 0 (x+24)(x-5) = 0 so five
*July 1, 2015*

**math in distress**

LOL, English units bother me almost as much as the confusion between bearing and heading in mathematics texts :)
*July 1, 2015*

**math in distress**

Metric spoils all the fun. Remember: 1 slug = 1 pound/g = (1/32.174049)pounds on the surface of earth only.
*July 1, 2015*

**Statistics**

This might help: http://davidmlane.com/hyperstat/z_table.html
*June 30, 2015*

**typo**

2 inches = 1/6 foot
*June 30, 2015*

**math**

volume of stuff is 2 inches times (area of outer circle - area of inner circle) 22 inches = 1/6 foot 1 yard^3 = 27 ft^3 so 27 = (1/6)(pi)(R^2 - 5^2) solve that for R then width of path = R-5 in feet
*June 30, 2015*

**Chemistry**

You are welcome. Good luck.
*June 30, 2015*

**Chemistry**

I prefer that to your cathode ray tube, but you better add explanation of why some are falling and some are rising :)
*June 30, 2015*

**Chemistry**

I think it might be a good idea to read up on the Millikan oil drop experiment. For example: http://felix.physics.sunysb.edu/~allen/252/PHY251_Millikan.html
*June 30, 2015*

**physics**

East velocities + momentum before = 0 so momentum after = 0 1 * 8 + 5 * v = 0 v = 8/5 west
*June 30, 2015*

**mathematics :geometric progression**

k-3 = a r a = 2k-4 r^2 a = 4k-3 ------------------- r= (4k-3)/(2k-4) = (2k-4)/(k-3) so (2k-4)^2= (k-3)(4k-3) 4 k^2 -16 k + 16=4 k^2 - 15k +9 -k = -7 k = 7 go back and find a and r
*June 30, 2015*

**Differential calculus**

I think you probably mean V = Vo e^(-t/RC) where Vo is 300 volts and the chrge is discharged through the resistor here 1/RC = 1/(.12*4) = 2.08 so V = 300 e^-2.08 t dV/dt = -2.08(300) e^-2.08 t = -625 e^-2.08 t volts/second obviously when t = 0 this is -625 you can put in .5 or...
*June 30, 2015*

**Math**

distance = rate * time :)
*June 30, 2015*

**Physics 12-grade**

If W1 = f(x1,y1,z1) and W2 = f(x2,y2,z2) then the work from point 1 to point two is W2-W1 the work going back is W1 - W2 the net work for the round trip is zero. That is the point. If you can define potential as a function of position, the field is conservative. It is really a...
*June 30, 2015*

**Physics 12-grade**

That is the whole point of a potential field. It does not matter you you get from point x1,y1,z1 to point x2,y2,z2 The work done is the same by any path. It may not seem that way if you are taking different trails, steep ones that go up and down and easy ones with a constant ...
*June 30, 2015*

**Physics 12-grade**

If the work done is a function of x y and z, then the force is conservative.
*June 30, 2015*

**statistics**

Now wait a minute. You are asking a lot of questions some of which I am sure you can do. For example in number 31, it is clear that only 1,3,and 7 are in both A and B Please do not ask us questions without trying yourself and posting your attempt. I do not have your font for ...
*June 30, 2015*

**math**

I guess you mean that 70% studied? If so then if there were 100 students: 70 studied, 66.5 passed 30 did not study, 18 passed so out of 100 students 84.5 pass so .845
*June 30, 2015*

**math**

as n---> oo the term -----> n^2/(4n) or n/4 or oo so for sure it does not convergerge. n=1, 1/5 etc down to n = 5, 25/21 now try n = 10 100/41 , starting to climb
*June 30, 2015*

**physics**

You are welcome.
*June 29, 2015*

**physics**

(1/2) m v^2 = m g h v^2 = 2 gh v = sqrt (2 g h) = sqrt(2*9.81*4) = 8.86 m/s
*June 29, 2015*

**physics**

u = 5 m/s forever v = -g t h = 5 - 4.9 t^2 h = 0 at ground so 4.9 t^2 = 5 t = 1.01 seconds so v = - 9.81 * 1.01 = - 9.91 m/s speed = sqrt (5^2 + 9.91^2) = 11.1 m/s in other words I dissagree with jzee11
*June 29, 2015*

**physics**

1. initial kinetic energy = (1/2)m (225) went down from 20 meters to 10 meters potential energy went down by m g h = m (9.81)(10) so gain ke of m (9.81)(10) so now total ke = (225/2) m + 98.1 m = (1/2) m v^2 so v^2 = 2 (113+98.1) 2. same as 1 above ke at bottom = (1/2) m (400...
*June 28, 2015*

**can not**

Need to know more. For example is theta the same for both?
*June 28, 2015*

**Math**

let's say I could by a cup of coffee for 100 birr at the end of 2007 at the end of 2008 that cup would cost 141 birr so I could only buy 100/141 or .7092 of a cup at the end of 2008 my buying power has gone down 1-.709 = .2907 or 29.1 % because I lost 29.1 percent of my ...
*June 28, 2015*

**Math**

(1/4)(13/51)
*June 28, 2015*

**Math**

10*9*8 = 720, not 518400
*June 28, 2015*

**Math**

90*8 - 720
*June 28, 2015*

**Math**

Google "permutations" by the way.
*June 28, 2015*

**Math**

10! /(10-3)! = 10!/7! = 10*9*8
*June 28, 2015*

**I doubt this data**

coef of friction = 9.60 ? That is very unusual. Is a slap a slab ? Is a flow something a floor? There are two conditions here. The first is before the block starts to slip on the slap and the static friction rules In that case F = 100 N m = 40 + 10 = 50 kg a = 100/50 = 2 m/s^2...
*June 28, 2015*

**St. Basil's school. Physics**

T - 2 pi sqrt (L/g) or in other wors T = k sqrt L 1.44 /.36 = sqrt L1/sqrt L2 L1/L2 = (1.44/.36)^2
*June 28, 2015*

**Physics**

North of east is not a direction Do you mean Northeast? North by East? North North East ? I will assume Northeast which is 45 degrees north of east If so then: North 3 + 5 sin 45 = 6.54 East= 0 + 5 cos 45 = 3.54 distance = sqrt (6.54^2 + 3.54^2) = 7.43 miles tan angle north of...
*June 28, 2015*

**chem org**

bond of two polar molecules one side +, the other side - Try water for example http://www.google.com/search?q=dipole+dipole+bond+examples&ie=utf-8&oe=utf-8
*June 28, 2015*

**physics**

F = G M m/R^2 F/m = G M/R^2 = g wherever G Me/Re^2 = g earth G Mm /Rm^2 = g moon so g moon / g earth = (Mm/Me)(Re/Rm)^2 = (7.36/5.98)(10^-2)(6.37/1.74)^2 = .165 1/.165 = 6.06
*June 28, 2015*

**Algebra**

if 3 x = 18 divide both sides by 3 similarly if 25 x = 50 divide both sides by 25 115 + 118 + 81 + 8 = 322 so 2 x + 322 = 360 subtract 322 from both sides 2 x = 38 divide both sides by 2
*June 28, 2015*

**math**

10 /x^2 = 3 3 x^2 -10 = 0 x = [ 0 +/- sqrt (0 + 120) ] / 6 x = sqrt(120) / 6 = sqrt(30) /3
*June 28, 2015*

**physics**

F = k x = 2.5 Newtons You can not find the period without knowing more, for example the mass. 2 pi/T = sqrt (k/m)
*June 27, 2015*

**Math**

Yes
*June 27, 2015*

**Calculus, derivatives**

they just add dy/dx = a^x ln a + a x^(a-1)
*June 27, 2015*

**calc**

circles stacked to make hemisphere of radius 4 Volume = (1/2) (4/3) pi r^3 = (2/3) pi (4^3)
*June 27, 2015*

**Physics**

cos 45 = sin 45 so both are 550 cos 45 = 550 (sqrt 2)/2
*June 27, 2015*

**Physics**

question does not make sense. What is the heading?
*June 27, 2015*

**science**

The same folks say that pi is 3.00 :)
*June 27, 2015*

**alegbra**

8 x^2 - 7 x - 6 = 0 x = [ 7 +/- sqrt (49+192)] /16 x = [ 7 +/- 15.5 ] / 16 x = 1.406 or -.531
*June 27, 2015*

**Pre Calculus**

4 along x axis 9 along hypotenuse sloping down so y = - sqrt(81 -16) = -sqrt(65) so sin T = -sqrt(65) /9 so csc T = 1/sin T = -9/sqrt 65 cot T = cos T/sin T = (4/9 ) / -(sqrt 65)/9 = 4/sqrt 65 = (4 sqrt 65) / 65
*June 26, 2015*

**Math**

A 10 + 4 = 14 so yes B 16+3 = 20 ??? C 2 - 13 = -11 which is not to the right of -10 on number line D 18 + 15 = 33 is less than or equal to 31 ???
*June 26, 2015*