Posts by bobpursley
Total # Posts: 47,518

Physics
consider mass, time, and length in your description. 
Physics
PE at that altitude: mgh=1/2 m v^2 g=GMe/(Rearth+1.5e^6)^2 v=sqrt(3e6*g *2) use g from line above. 
Math
take the implicit derivative. 2x Dx 7y^3*2x Dx7x^2*3y^2 Dy=2yDy2xDy2yDx Dx(2x14xy^3+2y)=Dy(2y2x+21y^2) solve for Dx/Dy, then put in the point (2,5) and solve. check my work. 
physics
net force pulling: g(m2m1) F=total mass*a a= g(m2m1)/(m2+m1) d=1/2 a t^2 solve for t. 
Physics
What is it you do not understand about this? https://www.softschools.com/formulas/physics/parallel_axis_theorem_formula/346/ 
Physics
1/2 mv^2=mgh Vescape= sqrt (2gh) but g=GMj/d^2 so... Vescape=sqrt(2GMj/h) 
chemistry
Draw the lewis strutures first. Now consider https://viziscience.com/wpcontent/uploads/2017/09/s2cl22.jpg If that is the structure, how could it possibly be a polar (one end charged)? 
English
It seems to me you discussed issues, but you never addressed What Is the Secret to Reaching Someone With Words? a) consider using powerful ideas that they understand b) sticking to the topic, letting them figure the details (there is no better teacher than experience) Now on ... 
Charges
why do you have absolute signs on the charges. The sign of the charge is important. force=kq(q)/3^2 + kqq/6^2= kqq(1/9+1/36)=kqq(4/36+1/36)=kqq*3/36 where q=3e6 
chemistry
Nuts to just giving you the answer. 
science
first, I like D. A is ok on second. 
Science
electric fields is away from positive charges, by definition. 
math:^]
a. PQ=(75)x+(34(y)=2 ,1 RS=(48)x+(16)y=4,5 PQ+3RS=2 ,1 +3( 4,5)=(214,115)=10,16 magnitude= sqrt(10^2+(16)^2)=sqrt(356) factoring 356 2*178 2*2*89 magnitude=2sqrt(89) 
science
thanks. Is there a question here? Were they pushing in the same direction? 
LA
http://sabian.org/looking_glass6.php Ok, after the first page or two....Alice is becoming sensitive, avoiding confrontation, avoiding arguing, and Humpty is..... Did that dialoge help you develope who Alice was, and who Humpty is? 
Vectors
speed relative to ground: 240E+65*cos45E+65*sin45S combine like directions, then directionactual= arctan(S/E) south of East. 
Math
Hmmmm. Triangles? Not enough info. 
Shell Method
here it is about y=0. So the radius will be from y=y0 to y. https://www.khanacademy.org/math/apcalculusab/abapplicationsdefiniteintegrals/abshellmethod/v/shellmethodforrotatingaroundhorizontalline see if that helps. 
Chemistry
dissociation: lactic acid>>>H+ + act ka= x*x/(.025x) but you know x=10^2.74=.001819 ka= .001819^2/(.025.001819)=.001819^2/0.023181= 0.000142735904=10^3.85 pKa= 3.85 check my math 
Angular acceleration
well, in each rotation of the wheel, the wagon goes 2PI*r speed car=2PIr/timeforonerotation=w*r w=speedcar/r so change those speed in km/hr to m/s, find wi and wf angacceleration= (wfwi)/3sec 
Science
adding more lightbulbs will make them dimmer. the current in a series circuit is CONSTANT in each part of the circuit. 
chem
the max volume is 10 ml. the 6 Molarity is the concentration of the HCl. You dont do anythign with that number. 
Science
Primary sources can be used directly, as they appear in the natural environment: coal, oil, natural gas and wood, nuclear fuels (uranium), the sun, the wind, tides, mountain lakes, the rivers (from which hydroelectric energy can be obtained) and the Earth heat that supplies ... 
Physics
sum of heats gained is zero. heatgainedhotwater+heatgainedbycoolwater=0 120*c*(Tf50)+200*c*(Tf10)=0 solve for Tf 
Physics
and your work is? Snell's law is pretty straight forward. 
Physics
Snell's law applies. The angle has to be measured from the normal, I assume by "prime" you mean normal. 
Physics
even if they are end to end, the sum will be 25. 
Algebra (Final)
If it is not in your text, burn your text. https://www.varsitytutors.com/hotmath/hotmath_help/topics/sumofthefirstntermsofageometricsequence 
Math
area=PI*r^2 r= sqrt(area/PI) 
Math (Trigonometry)
sin(5x)=sin(4x+x)=2sin4xsinx 
science
glass 
Math
of the 20x5 groups above, there are 11 with two or more late (**** means 2+late) 65926, 31459, ***31986, ***65809, 80462 ***27387, ***39075, ***46738, ***21986, ***59837 ***91384, ***10987, 26491,*** 68498, ***98796 32596, 26448, 31235, 63256, 53121 Pr=11/20 
Chemistry
amount left=65*e^(.693*15/3.8) put this in your google search window: 65*e^(.693*15/3.8)= 
Maths
L is longer ribbong length, S is shorter ribbon length L17.5=S L/3=3S/4 L= 9S/4 9S/4 17.5=S S(9/44/4)=17.5 S= 4*17.5/5=14 inches 
Sci
if you destroy wetlands, you are probably not changing the ozone layer. 
math
I already took the course, and test. What is your difficulty with this? Seems to me you need a pencil and graph paper, or a graphing calculator. 
Algebra 1
rate combined=sum of rates= 1trip/1.5hr + 1trip/1hr= 2.5trips/1.5hr time to deliver= trips/rate= 1.5/2.5=3/5 hr 
Algebra 1
let E be weight of expensive nuts, C be cheaper nuts E*8+C*5=10*6 value equation E+C=10 mass equation Solve it by any method, I will do determinants Det: 85=3 E= (6050)/3=10/3 =3.33 lb C= 8060 /3=20/3 =6.66 lb 
Science
if you blow air thru a straw into a jar of lime water (CaO), it turns cloudy precipitating CaCO3. https://www.youtube.com/watch?v=xOoutdcVWI 
english
I only see bluntness. I think she is being stark blunt 
Calculus
have you seen this? https://www.youtube.com/watch?v=fjcHK6GGqm8 
Math
if secTheta=13/5, then cosTheta=5/13 cos^2 + sin^2=1 sin^2=125/169=144/169 sinTheta=12/13 (in second quadrant, positive0 sin(2Theta)=2sinTheta*cosTheta=2(12/13)(5/13)= you do it. check my thinking 
Chemistry
No 
Chemistry
if H+ is 10^5.35, so the acetate concentration the same. H acetate>><< H+ + aqcetate 
Physics
none are correct. Number 2 question is technically and issue of the word "stronger". Stronger in what sense? tensile strength? Magnetic properties? ductle? Ferrite is a brittle ceramic material, as the question is written, I would go with that. It is a poorly worded ... 
Physics
and your thinking is???? 
physics
vf2=vi2+2ad so take the square root of your v2 
physics
3. vf^2=vi^2+2g*3.8 will do it 4. same formula. vf^2=vi^2+2ad 
Social Science
First, understand what a manifesto is: a public policy statement of goals and vision. Examples: a. <<And with your courage and with your compassion and your desire, we will build a Great Society. It is a society where no child will go unfed, and no youngster will go ... 
history
that link is an excellent summary of what happened, but obviously, Napoleon would not agree with the outcomes as stated....He would have preferred a spin that favored him more as the person who was making France great again. He liked to be the star of the show, pushed himself ... 
Chemistry
How many mL of water would you add to 32 mL of 0.62 M ammonium chloride stock solution to make a 0.3 M solution? >> Another method. You are diluting it .62/.3 = 2.06 times. That means one part original, and then add 1.06 parts water. if one part is 32ml, then 1.06 parts ... 
Science
correct. 
vectors
https://answers.yahoo.com/question/index?qid=20090914114948AAF9qjv 
math
10/25=40/100= 40 percent 
Physics
What is the wire wound around, or specifically, its permeability? http://hyperphysics.phyastr.gsu.edu/hbase/magnetic/solenoid.html#c3 
Science
heat=mass*heatvaporiazition. 
Chemistry
It shifts to the left. More H2, more I2 is made, less HI, energy is absorbed (endo), 
Physics
vf=at solve for a. put km/h into m/s, and 5min into seconds. 
Algebra
multiply by sqrt30/sqrt30 you now have 4sqrt6*sqrt30/30 but sqrt 30=sqrt(5*6)=sqrt5*sqrt6 now you have 4sqrt6*sqrt6*sqrt5/30=24*sqrt5/30=.8 sqrt5 
Chemistry
find moles of O2: 41.9/32= ... then, PV=nRT or T=PV/nR you have n, Pressure, Volume find temp triple check your units on R You need R in atm, liters, psi, temp in K 
Science
a is correct 
physics
There are a few fundamental characteristics of matter we have: a. That matter is a form of energy. b. That particles can have mass, charge, momentum, and have many characteristics of waves. c. Charge seems to be based in the fundamental characteristics of one of the quarks, ... 
Chemistry
heat=mass*specheat*tempchange=122g*4.18J/(gC)*23C 
Physics
sketch a diagram. How how off the ground is the child at the 30 deg point: Ans: h=2(1cos30) a. child speed at bottom: KE=initialPE 1/2 m v^2=mgh v= sqrt (2gh) b. energy lost: initial PE1/2 m(2)^2 
Science Answer Check
7. there is a better answer. 
Chemistry
yes, particles separate, thermal expansion 
Algebra
If 3 were one die, then the possible sums of two dies would be 6,5,4,3,2,1: avg 3.5 if 2 were one die, then the possible sums of two dies would be 5,4,3,2,1,0: avg2.5 the figure all possibilities for the first die, and the avg sum on each. Add all the sums, ... 
Physics
sum of heats lost is zero. .022*Hf+.450*Cw(80Tf)+.022(Cw)(0Tf)=0 solve for Tf 
geometry
volume=h*PI*r^2 smallest height will be at 7cm 315/PI*7^2=2.05cm largest height will be at 6.5cm 315/(PI* 6.5^2)=2.37cm 
Chemistry
Na*Va=Nb*Vb .5875*3*10ml=.2625*Vb Vb= 10ml*(.5875/.2625)= about 22ml in my head 
Science
abiotic. No including living things. Not A 
social studies
https://history.libraries.wsu.edu/fall2015/2015/08/30/changesinoilpricesandhowtheyaffectdifferenteconomies/ 
Science
What are factors in burning: Heat, Fuel, Oxygen. So hot temps mean more heat, so burning is increased. 
Math
Hmmmm. I bet his horse's name is Sunday. 
physics
vfinal=acceleration*time change km/hr to m/s 
socials
They raised Hell to get the right to vote, and a constitutional amendments was passed to give them that right in US elections. Men in those days didn't think women were smart enough to vote. 
physics asap
I just did the first on below. 
physics
his final KE=KE at launch + PE at launch 1/2 mv^2=1/2 m 4.7^2 + m(9.8)(3.8) V^2=44+37 v= 9m/s 
Chemistry
1. You need no website. If half is gone after 20 days, then after 40 days, half of half is all that remains: 1/4*200=50g 2. Molarity= mass/molmass * 1/volumeinLiters = 19.3/formalamassNaCl * 1/4 formula mass Na=23+35 check that. 3. pH+pOH=14 pOH=log(OH)=log (10^9)=9 PH=149=5 
Chemistry
they move apart. 
Chemistry
they get closer together, and collide more often, and collide more often with the walls of the container. 
Physics
time it takes the coin to fall: h=1/2 g t^2 t=sqrt(2h/g) time it takes sound to come back: h/vs given: those times add to 5.2 seconds 5.2=sqrt(2H/g)+h/v a quadratic: let u=sqrt h so u^2=h u^2/v+u(sqrt2/g)5.2=0 u^2+u*vsqrt(2/g)5.2v=0 calculate v for that temerature, then use ... 
Math (Help)
notice for each increase in x of one, y goes down by 5, so it is a linear equation. general form: y=mx+b using two data points (2,9; 2, 11) 9=2m+b 11=2m+b add the equations 2=2b or b=1 with b=1, then 9=m(2)1 m=5 y=5x1 should do it. 
CHEMISTRY
changing concentrations to Normality: 2.5e2 M= 5e2N on sulfuric .03M KoH=.03N KOH Na*Va=Nb*Vb Va=(.03/5e2)125ml=75ml 
Social Studies
Wouldn't it depend on your product or service you are planning? http://francistapon.com/Books/TheHiddenEurope/WhereisEasternEuropeandwhatcountriesareinit 
Chemistry
you have 3.44/1.86 moles. molemass=11.32*3.44/1.86 
Maths, physics, science
rate=volume(time) rate*time=volume time=volume/rate= 1.5m^3/(PI*25*3) seconds 
Social Studies
On the peace question, A is probably the best answer, but with fingers crossed. Bill Clinton did make the hyprocrisy of the UK evident, and it did spur some movement. On the second: lower interest, easier money, more things are bought. Why would anyone default on a loan if the... 
Science
just follow the directions. 
Chemestry
assume 100Liters, mass then is 89.7 grams PV=nRT so you have P, v(100lites), n=mass/molmass and you know mass, Look up R for your units, and you know temperature 
chemistry
molarity=(:mass/molmass)/volume mass=molarity*molmass*volume=58.4*1.0*.300=17.5grams 
Chemistry
So what is the other 9 percent of the unknown compound? 
Chemistry
you percents only add to 91 percent 
Quadratic Functions and Equations
well, the dimensions of each end is (25+2w)w and the side (100w). the total lawn area A=2(25+2w)w+2(100w)=50w+4w^2+200w=4w^2+250w=2*2500 4w^2+250w5000=0 w^2+62.5w1250=0 solve the equation. check my thinking d 
ELA
C is ok. 
physics
mass=density*(thickness)(diameter/2)^2*PI = 7500*.05*(.250)^2* PI=73.6kg check my calculations 
math
in matrix form 6,3,10 2,1,9 3x r2, add r1,r2 12,0,37 x=37/12 
Chemistry
I recommend look at the definitions of each: keyword: google search. 
Math
correct 
Physics
66=h1h2=1/2 gt^21/2 g(t1)^2 solve for time t.