Thursday
March 26, 2015

Posts by bobpursley


Total # Posts: 37,658

Physics
hf=hi-1/2 g t^2 -300=-4.9 t^2 solve for time t.
March 26, 2015

chemistry
I have no idea what the reaction is. I am surprised your chem teacher has not counseled you yet on the math issue.
March 26, 2015

Physics
vf=vi+gt =20-9.8*2 m/s If you round to ten, vf is zero. Why do folks use 10m/s^2 as g? Nowhere on the Earth is it that value. Why not use 3.0 as PI?
March 26, 2015

CHE107
There are avag number of molecules in a mole, but in NaCl, there are two atoms per molecule, so Number atoms: avagNumber* 2
March 26, 2015

Business
I am not certain what an "executive administrator" is, or what she does. If she were the boss of the managers, she ought to tell them to either negotiate, or let her do it. Or fire them.
March 26, 2015

Geometry B
yes, if it really a kite (geometry) shape.
March 23, 2015

physics
and the distance it has went is 1/2 vf*time
March 23, 2015

physics
Vf^2=2ad vf=at so (at)^2=2ad a=2d/t^2=2*.65/(.5)^2 Now that you know a, vf=at when t is three
March 23, 2015

critical thinking
examples: A. were you hit? B. you hit me silently. C stop hitting me D Blue Chickens accuse? D is the wrong form. We Accuse blue chickens.
March 21, 2015

science
initial difference in A and B=46C four min later they are 16C apart, they have went 16/46 (about 1/3 the way) initial difference in C and D are 46C four min later they are 10C apart, they have went 10/46, or about 1/5 they way. C and D are exchanging heat much more slowly than...
March 21, 2015

science
I think you need to look at the rate of cooling, ie,how fast they are changing. Exactly what is that k in the exponent?
March 21, 2015

science
yep
March 21, 2015

science
Nope, in several hours, both will went half way (intial temp differnece is 40C, so both move 20 C, to reach final temp of 60C.
March 21, 2015

science
see the last problem. you do it this time.
March 21, 2015

science
initial temp difference is 85-40=45 C half way then is 85-45/2=62.5 C
March 21, 2015

science
Ok, sixth grader answer. You know the final temp in each will be an equal 62.5C (half way between 85 and 40). Think out why..there were equal amounts of liquid, the same liquid. So each has to change by half way, or 22.5/2 = 11.2C. Now look at liquid A. It stated at 85, in ...
March 21, 2015

science
sixth grade, ok, I figured you were in college. This is a college question. give me a couple of minutes.
March 21, 2015

science
The temperature changes are exponential. The initial difference was 68-40=28 after 5 min, the difference was 25 C after infinity, the difference will be 0C so I model the temp differnece as TempDiff=28e^kt so lets solve for k at the first five min mark 25=28e^5k or ln (25/28)=...
March 21, 2015

science
I think you are guessing. if they are exactly the same, the amount of heat one loses changes the temp the same amount as the one gaining.
March 21, 2015

English
You can do citations any way your heart desires...I go with the old Chicago style book I learned at the University of Texas in 1960. However, styles change. So use whatever your heart desires. Now if your teacher told you to use MLA, or APA, or else, you need to use those for ...
March 21, 2015

science
a. Adding OH increase the products, so the reaaction will try to undo that and move to the left. b. adding H+ increases the prducts, so the reacation will try to undo that adn move to the left. c. shifts to the right to undo the adding of the OH d. shifts to left to reduce the...
March 20, 2015

physics
1/di+1/do=1/f 1/di+1/24=1/10 24/di=2.4-1 di=1.4/24 meters=1.4/24 m then M=di/do=hi/ho solve for hi, about ho*di/do=160*1.40/24
March 20, 2015

physics
ok, vf^2=2ad acceleration=50/mass-20g*cos3.0/mass-.1*g*sin3.0 solve for vf then, KE increase=1/2 m vf^2
March 20, 2015

English
forget the intro for now. What do you want to say? Write out a outline of maybe one to three points you want to make. Now, on those points, what evidence or arguement can you make to support that point? Start writing a draft of paragraphs to support your points. Now, do you ...
March 20, 2015

math
net force=mass*acceleration mg-200v=m*a a=g-200v/mass note we have a sign issue. if g is always downward, then if v is upowrd, then a=g-200v/m but when the motion is downward, a=g+200v/m because v is now a negative sign....so on part b), one has to change the sign.. a) now we ...
March 20, 2015

life orientation
Only two? Rivalries and jealousy between cities.. wasted economic resources building stadiums.
March 19, 2015

math help please
yes
March 19, 2015

Chemistry
The 3 comes from the valence of Fe, which in this case is +3, given However, in nature, Iron reacts with dilute sulfuric acid to produce IronII sulfate and hydrogen. In Nature, iron reacts with concentrated sulfuric acid to produced IRON II Sulfate and sulfur dioxide (and ...
March 19, 2015

Math Help
You dont get it ... I think you meant this: 3/(x^2+x-2)=-1/x+2+1/x-1 factor the left side: 3/((x+2)(x-1))=A/(x+2) + B/(x-1) Now to solve A and B 3/((x+2)(x-1))=(A(x-1)+B(X+2))/((x+2)(x-1)) now comparing numerators, 3=Ax-A+Bx+2 and from that, Ax+Bx=0, or A=-B and -A+2=3 or A=-1...
March 19, 2015

Math Help
Your non use of parenthesis makes this problem undecipherable.
March 19, 2015

Math
You have to use the tools you have learned, which I have no idea what you have studied. Your calcualtor can solve this very rapidly, using Gaussian Reduction. You can use determinants, or elimination of variables. for instance, take the last two equations. Double the last one...
March 19, 2015

Life orientation
Types of representative democracy include: Electoral democracy – type of representative democracy based on election, on electoral vote, as modern occidental or liberal democracies. Dominant-party system – democratic party system where only one political party can ...
March 19, 2015

Chemistry
a. calculate the moles of reactant/products for the givens. b. use the mole ratio in the balanced equation to calcuate the unknowns. c. reconvert to mass. Example: Number 3 3Cu + 8HNO3 --> 3Cu (NO3)2 + 2NO + 4H2O given 356 grams Cu(NO3)3, or 356/187.6 moles (which is equal ...
March 19, 2015

Physics
1/2 mv^2=1.2 k x^2 solve for v
March 18, 2015

physics
fw+T=46*9.8 vertical forces. summing now about the wall.. 46(9.8)*1=T*2 tension=23*9.8 fw= First equation=you do it.
March 18, 2015

physics
time=d/5.04 time=(d+17.5)/7.26 set them equal, solve for d
March 18, 2015

Math
neither how much is five plus eight?
March 18, 2015

chemistry
Ionic? Zn + Fe+2 + SO4-2>ZnSO4 + Fe(e)
March 17, 2015

Vectors
add the two equations >>>z=-10 that allows only a) to be the answer.
March 17, 2015

Algebra Help please
that is not the answer, you need to find a, b, c.
March 17, 2015

Chemistry
No idea where to start? Read about bauxite in wiki. bauxite + sodium hydroxide>aluminum hydroxide+ heat aluminum oxide + heat + electric current> aluminum http://en.wikipedia.org/wiki/Bauxite#Processing
March 17, 2015

physics
without the picture, I have no idea.
March 17, 2015

chemistry
balance the equation: 3H2+N2>>2NH3 so you get 2/3 of the moles of Hydrogen gas.. moles H2=PV/RT
March 17, 2015

Algebra
Nope, nope.
March 16, 2015

Algebra
sinx=4/5
March 15, 2015

math
one line: y=mx+b second line perpendicular y= -x/m + c of course, you have to know m, b, c.
March 15, 2015

Physic
a. F=k/r^2 f'=-2k/r df/dr=-2k/r at r=20k -3=-k/20000 k=60,000 N so when r=10,000 df/dr=-60,000N/10,000m=-6N/m CosTheta=x/5 -sinTheta*dTheta/dt=dx/dt *1/5 but sinTheta= sqrt(5^2-x^2)/25 sinTheta=sqrt(1-(x/5)^2) solve4 for dThteta/dt
March 15, 2015

precal
Is there a question here? My crystal ball is on the blink.
March 15, 2015

Physics
energy lost in friction: mg*cosTheta*mu*distanceupplane KE lost going up the plane: mg*SinTheta*distanceupplane add those, set them equal to initial KE.
March 12, 2015

math
angle of hour hand: each 12 hours, it goes 360 deg Angle hour hand= 360*(6 48/60)/12 Angle minute hand: each hour it goes 360 det Angle Minute Hand: 360*(48/60) now subtract one angle from the other, that is the difference in angles.
March 12, 2015

Physics
tension=mg*cosTheta+v^2/r You know cosTheta, it is (1.52-.775)/1.52 solve for v at that point. Now figure total energy of the block bullet...you know KE+ PE totalENergy=1/2 m v^2+ m g h that energy is the same energy of the block when it absorved the bullet... solve for ...
March 12, 2015

Chemistry help please
pressure is directly proportional to temp in Kelvins. So change temps to K emperature(K) pressure(mm of hg) 283 726 293 750 313 800 263 880 393 960 423 ??? Now do a proportion PPP/423=960/393 check all my temp conversions, solve for PPP
March 12, 2015

chemistry
K= [B]^2*[C}/[A]^2 A=(.6-x)/4 B= (x) C=(x/2)=.2 use C to solve for x, then solve for the rest.
March 12, 2015

chemistry
ratio? O/NO=1/2 No/NO2=2/2=1/1
March 12, 2015

Physics
gravity force down the plane=mg*cosTheta friction force=mu(mg*sinTheta+F) set them equal, solve for F
March 10, 2015

Science (Chemistry)
two errors. 4*4*4 is NOT 36 the answer should be only to two sig figures.
March 9, 2015

Science
mass=density*volume=2.7*4.0^3 to two significant figures.
March 9, 2015

Physics
PV=nRT n=PV/RT use for R, units atm*liters/Kelvins change C to Kelvins
March 9, 2015

MATH!!! NEED HELP FAST!!!
C, of course
March 9, 2015

chemistry
You need to read your solubility chart. http://www.kentchemistry.com/images/links/Kinetics/Solubi1.gif what is the difference between the 80C and 10 C solubility?
March 9, 2015

physics
force*distancepushed=force*5 force=200*9.8*5/(5/sin25)=200*9.8*sin25 N
March 9, 2015

math
http://mathbits.com/MathBits/TISection/Statistics1/MAD.html mean: 3 difference: 1,1,2 mean difference=4/3
March 9, 2015

math
and the question is?
March 9, 2015

physics
Huh? This makes no sense.
March 9, 2015

physics
figure the time for each. Let d be half the distance. time1=d/80 time2=d/60 avgvelocity=2d/(time1+time2) so figure that out, I recommend do the math on time1+time2 first, solve the fraction issue...
March 9, 2015

physic ap
Nope, you are wrong. Vf=vo+g*t I have no idea how you got your answer.
March 9, 2015

chemistry
As written? As written, is says the heat of reaction is 3330J per .320g Na. lets do a proportion. 2molesNa/.320g=Hr/3330J change 2 moles Na to grms, solve for Heat of Reaction.
March 9, 2015

Physics
whatever the plane speed is, is your speed. If you walk in the plene, that walking is relative to the plane. When you jump up, and the plane is moving, the place you land is farther ahead, however, the plane has moved also, so in the plane, you land at the same spot.
March 8, 2015

Physics
acceleration=(wf-wi)/time = 2PI(.485-1.65)/12.2 displacement (radian)=avgspeed*time = 2PI(wf+wi)/2 * 12.2
March 6, 2015

social studies. NEED HELP ASAP
http://www.theweek.co.uk/middle-east/60339/eleven-things-women-in-saudi-arabia-cant-do They can vote this year in local elections.
March 6, 2015

Phsyics HELP!
The average velocity was30m/s time=distance/avbvelocity
March 5, 2015

Physics
vf^2=vi^1+2ad solve for d. Is it within the 250m runway?
March 5, 2015

physics
speed=distance/time=7.5m/s at the end, vertical veloicty=7.5 cos45
March 5, 2015

physics
angle=arc tan (2/6) IMA=3 normal force=mg=200*9.8 Newtons theoretical force=1/3 * 200*9.8 N
March 5, 2015

physics
h(t)=ho+vi*t-1/2 g t^2 ho=0 h(t)=10.1, time=1.6 solve for Vi distance to peak 1/2 mv^2=mgh solve for h
March 5, 2015

math
25 square feet.
March 4, 2015

Contemporary Child Day Care
romoting child development through parental training, among other factors, promotes excellent rates of child development-.[3] Parents play a large role in a child's life, socialization, and development. Having multiple parents can add stability to the child's life and ...
March 4, 2015

Algebra
Looks ok to me, that is the average hourly rate. Peraps the teacher is looking for the daily average rate of pay. first day=15/3=5 dollars/hr second day=45/8=5.5.63/hr avg daily rate: add them, divide by two.
March 4, 2015

Algebra
-6x = 75 x = - 75/6
March 4, 2015

Algebra
I4 has no slope. Hmmmm. That is imposible. The slope can go from negative infinity to positive infinity, inclucing a slope of zero. Now if you mean zero slope, then y= any number, it will be parallel to I4. Now when y=-3 is on the line, as given, the line is y= -3. You are ...
March 4, 2015

calculus
y=a^kx y'= k*a^(kx)*ln(a)
March 4, 2015

math
Try g(x)=x^2-2x+3
March 4, 2015

geography
Do we know where the middle is? We have not been able to see the edges yet. Whereever the middle is, we are accelerating away from it very rapidly.
March 4, 2015

physics
Is there a question here?
March 4, 2015

math
I am not certain what you mean by an area of 150+175t. 25*W=area solve for W.
March 3, 2015

math
And the question is?
March 3, 2015

Chemistry
Correct
March 3, 2015

Math
substution: y=2+2/3 x 2x-3(2+2/3 x)=6 2x-6-2x=6 no solution. graphing y=2+2/3 x one line y=2/3 x-6 second line. graph them, the lines are parallel, no solution
March 3, 2015

math
How many pieces? 3/4 is the same as 6/8 so there must be 6 pieces that are one eighth foot long, at least here in Texas.
March 3, 2015

Statistics
let me quote from a readable text: <<State the hypotheses. We begin by stating the value of a population mean in a null hypothesis, which we presume is true. For the children watching TV example, we state the null hypothesis that children in the United States watch an ...
March 3, 2015

islamic studies
Isn't this a matter of opinion? I see on cable TV lots of folks each night who seem to know the mind of God, and how to become pure of heart.
March 3, 2015

physics
what is 820 (25.9/9.8)?
March 3, 2015

Calculus, HELP!!!!!!!!!
Ok, I am lost without a picture.
March 3, 2015

Physics
first, you are adding to the normal force pushing downward. normal force=45SinTheta+mg
March 3, 2015

Chemistry
moles acid=moles base M*35ml=1.5*45ml M=? Your work makes no sense. You are supposed to be finding Molarity sodium ions
March 3, 2015

physics
Vf^2=Vi^2 +2ad so the question is, what is Vi? consider vf=vi+at Now you have two equations, two unknowns, Vf, and Vi. I would solve for Vi in the second equation, then put that in the first equation and solve for Vf
March 3, 2015

algebra
this is -+ one stad deviantion. 68 percent sare within one standard deviation.
March 1, 2015

physics
a= changevelocty/time=2(15/3.25)/3.25
March 1, 2015

Physics
at the top? g=v^2/r v=sqrt(gr)
March 1, 2015

Physics
I dont see how you handled the heat of vaporization. Sum of heats gained=0 11.4(-Hv)+681cwater*(Tf-25)+781cAl*(tf-100)=0 -11.4*540+681*1*(Tf-25)+781*.22*(Tf-100)=0 do the algebra, solve for Tf.
March 1, 2015

Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | Next>>

Members