Saturday
August 1, 2015

Posts by bobpursley


Total # Posts: 38,228

Chemistry extra tips
manganese(VI) oxide dinitrogen monoxide
July 31, 2015

Math
34.56 x3.002 is the same as 34x3 + 34x.002 + .56x3+.56x.002 so now note. the final decimal place will be decided by the last term above, .56x.002, or .00112 (five digits), which is the sum of the digits of the two numbers being multiplied.
July 16, 2015

PSYCH
http://www.intropsych.com/ch05_conditioning/taste_aversion.html And you are absolutely totally wrong.
July 16, 2015

college chemistry
Molarity of diluted acid: 12*(9.6/125) next, the titration equation: Na*Va=Nb*Vb 12*(9.6/125)*24=2*Mb*32.4 solve for molarity of base, Mb
July 15, 2015

South bank uni
y'=4x^3 y"=12x^2 y"'=24x the degree of the last equation is one, son one inflection point.
July 15, 2015

Physics
Something is missing here. Is this object in a force field as it moves?
July 14, 2015

tokarara
work=300cos30 * 20 N.m
July 14, 2015

physics
compute the diapole moment p (distance x charge) compute the E field between the sheets. Max U= pE
July 14, 2015

Math
energy=5hr*.115kw cost=energyinKW-hrAbove*9.41 cents/kwhr
July 14, 2015

saviour preparatory school
pressure=weightonEachFoot/areafoot =.25*500*9,8 N/.08m^2=12.5*.25*500*9.8 P
July 14, 2015

PHYSICS
positive interference will occur when the thickness is 360 degrees. One gets 180 phase change on the reflection, so thickness is 1/4 wavlength. I do not understand your thickness above, but you want thickness to be 1/4 *lambda
July 14, 2015

physics
density kid=mass/volume=70000g/80,000 cc = 7/8 g/cm^3 she floats density object=2000kg/1.5m^2 density water=1E3 kg/m^3=1500kg/1.5m^3 it sinks.
July 14, 2015

physics
height=1/2 g t^2 solve for t
July 14, 2015

Math
What is the question?
July 13, 2015

Algebra
now graph the two lines.
July 13, 2015

math
y(x+3)=-2x+1 does that help?
July 13, 2015

Physics
potential is the scalar sum... 1.26E3=k6.5E-9/.0201 + kQ/.0121 solve for Q
July 13, 2015

physics
The net force the "instant"? at t=0-, net force is zero at t=0+, net force is mg(.33-.11) The word instant can have many meanings.
July 12, 2015

Physics
vf=-vi as it returns to ground. -vi=vi+at 2vi=100 vi=50
July 12, 2015

Physics
vf^2=vi^2+2ad 50^2=10^2 + 2 a 60 solve for a. then, vf=vi+at solve for time t.
July 12, 2015

math
what is 4x5x20^2 ?
July 11, 2015

Physics
It must be when GM1/x^2=GM2(78-x)^2 solve fdr x The value of M3 has no significance.
July 11, 2015

Science
(Mt+Mb)g+(Mt+Ma)a)=166 solve for a. now, the aforce between the two boxes: Mt(g+a) is that force.
July 11, 2015

Science
Ff=Fx mg*mu=mv^2/r solve for v
July 11, 2015

Calculus Partial Derivatives
2w+2h+l<6 volume=lwh dv=whdl+hldw+lwdh=0 from the constraint 2dw+2dh+dl=0 so that is two equations, need one more. I dont see one. I suspect the problem meant for the girth to be a square, thus, h=w. In that case, two equations will suffice. dw=dh, and h=w 2dw+2dw+dl=0 or ...
July 10, 2015

science
avg velocity =30m/s vf^2=vi^2+2ad 2500=100+2a d or d=1200/a So new issue: we apply -a to stop it first. vf=vi+at=50-a*t or t=50/a to stop. it now has went a second distance of vf^2=Vi^2+2ad 0=50^2-2a d or d=1250/a+1200/a now on the return trip from the max total distance to ...
July 10, 2015

Algebra 2
when is height 300? 300<-16t^2+1000 -700<-16t^2 t<sqrt (700/16)
July 10, 2015

biology
Lymphocyte Main article: Lymphocyte Lymphocytes are much more common in the lymphatic system than in blood. Lymphocytes are distinguished by having a deeply staining nucleus that may be eccentric in location, and a relatively small amount of cytoplasm. Lymphocytes include: B ...
July 9, 2015

physics
sum moments about the fulcrum... 1.1*30-(L-1.1)43 - 20(L/2 -1.1)=0 solve for L
July 9, 2015

Physics
Figure the force on one of the corners (the sum of the forces from the three other corners). Then figure Q such that it balances this force. Force on one corner: kQq(1/s^2 *.707 + 1/s^2 (.707)+ 1/*sqrt2*s)^2) = kqq/s^2*(1.414+.5) check that I did it in my head. that is the ...
July 9, 2015

physics
workfriction=mgCosTheta*mu*distance so now is the distance the same?
July 7, 2015

Algebra 2
end behaviour is negative large for positive x. I dont know what you mean by "leading" term.
July 3, 2015

Physics
760mmHG is equvalent to 13.6*.760 m =10.34mH2O so add .470/10.34 *760mmHg to each of the readings. I get about 34.6mmHg added.
July 3, 2015

physics
Assuming your tension is correct, then the inward component of tension is what is counterbalancing centreptal force. horizontaltension=mv^2/r tension*sinTheta=mv^2/r 94.8*sin21=m (2PIr/Period)^2/r solving for period Period=2PIsqrt (m* r/94.8*sin21) check that.
July 3, 2015

Chemistry
In short: a cathode is heated until electrons are boiled out, then an accelerating field is applied which moves the electrons in a path towards phosphor coated screen. With suitable deflecting fields, the beam can be moved about to strike certain areas. A large positive ...
June 30, 2015

Psychology
It lends to the argument of nature (biological) control.
June 30, 2015

Chemistry
I agree with that.
June 29, 2015

Chemistry
Nope: Lead atoms and copper atoms pack about the same, with the exception that lead has a greater atomic radius than copper (.175nm vs .128), which when cubed gives a volume ratio of (.175/.128)^3 or 2.5. The atomic mass of Pb is 207 vs Cu 63, so the ratio of mass to is 207/63...
June 29, 2015

Stoichiometry chem
ok, at that point you know how many moles of CaCO3 you have. Now look at the formula: for each mole of CaCO3, there is one mole of C. Moles of C=250.0/100.1 to four decimal places (if your mole mass is correct)
June 27, 2015

science
PEchanbe=heatadded mgh=m c *(tf-ti) solve for tfinal tf tf=g*h/c + ti It never ceases to amaze me when folks use g=10m/s^2. Nowhere on Earth is it that value. Do they think students are imbeciles and can't use 9.8?
June 27, 2015

Pharmacy Tech Math
http://www.unc.edu/~bangel/quiz/testivh.htm
June 27, 2015

Chemisty
how many moles is 24g? then multiply that by -571.6kJ
June 26, 2015

math
Ms Sue is right, my divider is not working right tonite.
June 26, 2015

math
isn't that area equal to 5x6 sq yards?
June 26, 2015

physics
pulling work=800*cos37*8 Joules force friction: (mg-800sin37)mu friction work:(mg-800sin37)mu*8 net work. The pulling did work on friction and the movement net work=pulling work-friction work and the net work will equal the change of KEnergy of the boulder Notice above how ...
June 26, 2015

physics
work done=forceapplied*distance =.15*30*9.8*450 Joules
June 26, 2015

algebra
distance1=50t distance2=175(t-5) subtract first equation from second, solve for t: d1-d2=0=125t-5*175 divide by 5, then 25t=175 t=7 hrs distance=7*50
June 25, 2015

Algebra
ages then: n, n-2, n-4, n-6, n-2(13-1) so last kid is n-24 5*(n-24)=n n=5*6=30 youngestg will be 30-2(12)=6
June 25, 2015

physsics
momentum change = mass*changeinvelocity I wonder if "both" means masses added together.
June 25, 2015

Physics
friction force: mg*.387*Cos2.14 PE gained(due to change height)=mg*sin2.14*distance Initial KE+PE gained=frictionwork 1/2 m 5.15^2+mg*sin2.14*distance=mg*.387*Cos2.14*distance solve for distance
June 25, 2015

Science physics
MA= force output/force input = 30/2 / 10=1.5
June 25, 2015

Science Help. Thank You! (:
Energy Source % of total Natural Gas 46.5% Coal 15.5% Nuclear 14.9% Renewables 13.5% Large Hydro 9.6%
June 15, 2015

physics
what is sqrt(10^2+20^2) in the direction of arctan 20/10 E of N
June 15, 2015

physics
This makes no sense to me?
June 15, 2015

Science
Uracil
June 14, 2015

math117A
isn't this a ratio problem? 4.2/12.6 = 20.4/L L=20.4*12.6/4.2
June 14, 2015

Calculus
http://davidmlane.com/hyperstat/z_table.html set between -2 to +2 SDeviation, see that it is 95.45 percent
June 14, 2015

physical science chemistry
I will check your answers.
June 14, 2015

chemistry
both are monoprotic... Ma*Va=Mb*Vb Ma=Mb* Vb/va=.542*24.1/12.6=
June 14, 2015

Social Studies
https://en.wikipedia.org/wiki/Velvet_Revolution read the section "prior to the revolution"
June 14, 2015

biochemistry
https://en.wikipedia.org/wiki/N-terminus
June 14, 2015

math
mass of oil=density*volume=.90g/ml*18m^3 = .90kg/m^3\ * 18m^3 Weight of oil= above massoil* 9.8N/kg
June 13, 2015

Bernoulli equation
Without the figure... It sounds as if you need to compute the velocityh of the water coming out, then determine the distance it travels horizonally.
June 13, 2015

chemistry
take oneliter of the HNO3. weight=1500grams massHNO3=.63*1500 Molarity HNO3=.63*1500/63*1=15 Now you want to dilute it 15 times to get a 1 molar solution. That means one part HNO3 stock, 14 parts water. if the one part is 50ml, then water is 14*50=700ml, or .7 liter.
June 13, 2015

social studies
https://en.wikipedia.org/wiki/Independence_of_Brazil
June 12, 2015

Alg 2
other point? chose an easy x, such as x=0, compute y (y=29), and immediately you can use symettry for x=6, y=29
June 12, 2015

Science
you have the correct m/v density for the solution. I dont know what you were asked to do.
June 11, 2015

physics
work=m*g*height
June 11, 2015

science
avg velocity=distance/time distance = 1/2 a t^2 + vf*19 where vf=20*1.2 distance=1/2*1.2*20 + 20*1.2*19 time= 39sec compute avg velocity, distance/time
June 11, 2015

Chemistry
you want to dilute it 2.25/.750 times, or 10/3 times. Which means, one part stock, 7/3 parts water. What is one part? 7L/(10/3)=21/10=2.10liter So, take 2.10 l of stock, add to 7/3 * 210 l water, stir and label. BTW, 7/3*2.10 l is 4.90 l check: 4.90 + 2.1 l= 7liters
June 11, 2015

fundamentals of law for health information
bad publicity punishment in pain and suffering penalities opening up other similar cases to litigation.
June 11, 2015

Math
Pr(both engineers)= 4/10 * 3/9
June 11, 2015

physics
I will be happy to critique your work or thinking. It is not helpful for you to post several questions under several different screen names.
June 11, 2015

calculus1
there are two possibilities: The extrema is between -1,8 or the extrema is at the endpoints. f'=-2/3 x ^(-1/3)=0 or x=0 and at f(o) f(x)=1 f"=2/9 x(-4/3) and at x=0, this is positive, so f(o) is a relative min. Now examine the the endpoints: f(-1)=1-(-1^2/3)=1+1=2 f(8...
June 11, 2015

physic
without the figure, ....
June 11, 2015

calculus1
f'=0=2secxtanx-sec^2x secx(2tanx-sex)=0 secx=0 or tanx=1/2 secx which leads to sinx=.5 now, because secx cannot be zero, then sinx=.5 or x=30 deg or PI/6
June 11, 2015

k92 sec.
You will make two moles of SO2 for each mole of CS2 reacted. Moles of CS2: 2.00/molmassCS2 moles of SO2: twice the above STP volume of SO2: 22.4 x moles SO2
June 10, 2015

chemistry
thanks.
June 10, 2015

chemistry
Al: .038*.507 moles Cl: three times the above.
June 10, 2015

chemistry
Lets see: you want to dilute it by 2.73/1.68 or 1.625 times. Which means, you need one part KOH, and .625 parts diluting water. So what is one part? Easy: 153.2 is one part, and then water of 153.2*.625 ml water. Stir, label, and store properly.
June 10, 2015

Algebra 2
4x-32+10=-10 4x=-20+32=12 x=3
June 10, 2015

chemistry
.007 ppm. That is a very slight concentration, so you can safely assume one liter of solution has a mass of 1000grams. So, to get .007 ppm in a million grams of solution, you need .007 grams of sulfuric acid, so in a liter (1000 grams) you need : 7E-6grams of acid. 7E-6grams=...
June 10, 2015

physics
consider the fall: it fell for .8 seconds. consider the distance: velocity*time=3.1*.8 meters
June 10, 2015

phsics
It depends on how the interfernce is created. http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/gratcal.html
June 10, 2015

Physics
initial KE=7 final KE=7+25-frictionwork velocity is doubled, so KE is quadrupled. final KE=28J 28=7+25-friction solve for friction
June 10, 2015

Urgent - physics
This was one of my favorite physics labs...it got us outdoors in the spring. https://www.polarization.com/sky/sky.html
June 10, 2015

physics
reflections are polarized in the plane lying in the surface of the pond. Same issue as reflections off roads or automobiles.
June 10, 2015

Algebra
2x^2 + 9x + 4 = 0 (2x+1)(x+4)=0 x=-1/2, -4 (x - 5)^2 - 81 = 0 x-5=+- 9 x=14, -4
June 10, 2015

Physics
force friction=centripetal force mg*mu=mv^2/r solve for v then time=distance/velocity=5*2PI*r/v
June 9, 2015

physics
the rope is pulling, and lifting ... forcelifting=105sin37 force pulling=105cos37 forcepulling-frictionforce=ma=zero the problem is too easy...friction force=pulling force.
June 9, 2015

Physics
time=distance/velocity=120/200 seconds height fell=1/2 g t^2, and your about 5 feet is correct.
June 9, 2015

calculus1
I will start you ought. A neat way to get to near the solution is to graph cosx + x -2 look at where the graph crosses the x axis. Then change the limits on the graph to expand the area just around that intercept. Keep doing that until you can read it to 5 significant figures...
June 9, 2015

English
And at the Texas State Fair, one can get non-soft, no salt, non-twisted, with bacon. http://cf.creative-culinary.com/wp-content/uploads/bacon-pretzel-rods-unbaked.jpg What is that prezel like? An arrow headed toward your coronary arteries. What does that przel look like? A ...
June 9, 2015

calc
dA/dr=2PI r Put in r=3ft, calculate dA/dr
June 9, 2015

Math
I have a feeling some information is missing here.
June 9, 2015

Pre calculus/ Advanced Functions
I bet f'=-sinx
June 9, 2015

math trigonometry
factor left sinX)(sin^2x+cos^2X)= sinX*1 which does not equal the right. Lets look at the original idenity: at x=45 deg .707^3+.707(.707^2)= .707^3 * 2= .706 now, the right side for 45deg 1/.707=1.4 The indenity is not an idenity as you have written it.
June 9, 2015

math
let f(x)=3 for all x then abs(f(x)) is true but let f(x)=3 for all x>0, and =-3 for all x<0 then f(abs(x))does not equal abs(f(x)) so, I rate the statement sometimes true.
June 9, 2015

Algebra
avg rate= (f(x2)-f(x1))/(x2-x1) a. avg rate= (12-16)/(2)=-2 b. avg rate= (0-12)/2=-6 c( avg rate= (0-16)/4= -4
June 9, 2015

Algebra
y intercept is when x is zero. y=mx+b -6=1/5 *-3 + b solve for b.
June 9, 2015

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