Thursday
September 3, 2015

Posts by bobpursley


Total # Posts: 38,276

physics
Draw the figure. Note similar triangles. Let h be the height of the lamppost. h/(5.82+3.88) = 1.92/3.88 check that on your figure.
August 30, 2015

OChem
two.
August 30, 2015

Algebra II
The term geometric mean applies only to numbers with the same sign. Whoever gave you the problem made an error.
August 30, 2015

Calculus
y=( (8x-x^6)(x^-3) )^-4/5 y= ( (8x-2 -x^3) )-4/5 y'= -4/5 (8x^-2 -x^-6)^-9/5 * (-16x+6x^5) I dont think this is the same answer. Check both.
August 30, 2015

Calculus
correct
August 30, 2015

math
1. ok, you can forget worrying about the 12, as 24 is in the problem already (if it is divisible by 24, it is automatically divisble by 12). consider 16=4x4 20=4x5 24=4x6 you have four fours, but you will need a 5 and 6 to make a perfect square answer: 4^4 x 5^2 x 6^2=230400
August 30, 2015

Math (Ms.Sue)
each seat earned 10 dollars... money=10*nmberseats and the number of filled seats is given
August 28, 2015

PHYSICS
(4-(-2)+3Cx)i + (-5-1+3Cy)j=0 check that, then solve for Cx 4+4=-3Cx or Cx=-8/3 -5-1=-3Cy Cy=2 check all that, I did it in my head.
August 28, 2015

New Light Academy
volumemetal=outsidediaVolume-insidediaVol = PI/4 * (3.6^2 -2.8^2) per meter in cm^3/m mass60m=volume*density=volumeabove*.044kg/cm^3
August 28, 2015

Chemistry
calculate the volume of water displaced volume=masszinc/densityzinc now calulate the mass of water displaced mass=densitywater*volumewater now masstotal=211.6-masswaterdisplaced+10
August 27, 2015

Math
yes, real, and irrational. two plus PI is a real, irrational number
August 27, 2015

physics
well, it will be along the 60 degree ray force=14cos60
August 26, 2015

king senzangakhona high school
If this is a question, It makes no sense
August 26, 2015

Science
Poor question. One could argue B, and C also.
August 26, 2015

physics(measurement)
stack 50 coins, measure the height. then thickness will be height/50 another way. take 50 coins, measure the thickness of each with a micrometer. Take the average thickness.
August 26, 2015

chemistry
set both samples (at atmospheric pressure) in a dry ice box, once the both gases are liquified, remove them. The first to boil will be propane (bp -45F), followed by cyclopropane (bp -25F)
August 26, 2015

physics
I am not certain what you mean by "equal retardation". Is that equal force, or equally absorbing energy? Assuming equal force.. force*timeinPlank=mass*changeinvelocity force=mass*changeV/time=mass*acceleration so if each force is the same, acceleration is constant. ...
August 26, 2015

Physics
15cm? Wow. at the top, vf=0 vf=vi-2g(.15) solve for vi vf=vi-gt solve for time t at the top. now time of flight is 2*t vf=vi-g(2t)
August 26, 2015

Math
1.1/1.68=h/8.5 solve for h
August 26, 2015

physics
latent heat is energy that does not result in a temperature change. Latent energy is part of internal energy. some internal energy is available as potential energy
August 26, 2015

physics
Heatmelting=KE m*3.3E5=1/2 *2.5*5.7^2 solve for mass m
August 26, 2015

physics
1/2 *2.5*65^2 * 1/3 =internal energy
August 26, 2015

math
you have six digits repeating. multiply the number by 1,000,000 8714285.714285714285 subtract the original number -8.714285714285714285 notice the decimal portion disappears and you have 8714285-8, Work that out. Now, since you now have 999 999 time the original number, divide...
August 25, 2015

math
(sqrtm-sqrt7)/(7-x) multiply numerator and denominator by sqrtm+sqrt7. (m-7)/((7-x)(sqrtm+sqrt7))
August 25, 2015

math help
because multiplication of powers results in adding exponents, one can reduce this to 3^n*3^1 - 3^n*3^-2 3^n * (3-1/9)=3^n (2 8/9)
August 25, 2015

geometry
what is 2.25/1.75 ? (9/4)/(7/4)=9/7
August 25, 2015

science
Trick question. No reaction, all reactants and possible products (Ca(NO3)2 are soluble in the water present. Something has to be insoluble coming out of solution to be a reaction.
August 25, 2015

Math
volume=lxWxH=2*5.5*1.5= Pur this into your google search engine 2*5.5*1.5=
August 23, 2015

Right byte
to the right, or below the inserting. However, my workseet editor allows for also above, and to the left insertion.
August 23, 2015

math 540
http://www.zweigmedia.com/RealWorld/simplex.html you need to write your constraint equations.
August 23, 2015

Science
CORRECT
August 19, 2015

Math
1. You play a game where you score -6 points on the first turn and on each of the next 3 turns. What is your score after those 4 turns? For #1 I got -6(4) as the expression and -24 points after those 4 turns. Am I correct? YES. A very stupid game. 2. The outdoor temperature ...
August 19, 2015

physics
horizontally: work=force*distance=25*10 Joules At an angle: work=25*cos37*10 force is the force in the direction of movement...
August 19, 2015

Life Orientation
And in here in Austin, UBER is starting this month food delivery: you make your order from the resturant, UBER delivers it. Great for downtown folks, or those really busy. All on an UBER app...the resturant connection, and the delivery instructions.
August 19, 2015

physic
conservation of momentum... 7*9=(7+9)V solve for V
August 15, 2015

English
you are correct.
August 15, 2015

maths
I can make no sense of your question.
August 15, 2015

geometry d the sspeed of the bicycle in m/s
for each revolution, it goes PI*diameter on the ground. speed: PI*diameter/time time is one second. speed: PI*.77 m/s
August 15, 2015

physics
Aren't there standard formulas for all this?
August 15, 2015

Chemistry
I worked in in my head, 20 grams( forget my significant digits), so it looks like you are correct. Check it again, but it is reasonable.
August 14, 2015

Physics
gravity Earth=gravity moon GMe/(x^2)=GMm/(x-3.8E8)^2 solve for x
August 14, 2015

psychology
different cultures? Nuture must be different.
August 10, 2015

Physic
KE=1/2 m v^2= 1/2 .05*4^2 Joules distance=KE/force
August 10, 2015

Work like a scientist
Typically, one repeats the experiment again...just to be certain...
August 10, 2015

calculus
vf^2=vi^2+2ad change mph to ft/sec. then solve for a (in ft/sec^2
August 10, 2015

calculus
d=0=1/2 a t^2=12t^2-7.5t^3/2 t^2(12-7.5sqrtt)=0 sqrtt=12/7.5 t= that squared. check my thinking
August 10, 2015

physics
you have to add the angle for DISPLACEMENT. the angle is arctan(15/20) W of N
August 10, 2015

physics
vf=vi+at vi=200m/s vf=0 solve for a
August 10, 2015

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

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