# Posts by bobpursley

Total # Posts: 45,729

physics
yes. Inertial mass and gravitational mass are measured differently, and for many years there was a debate on the ratio, but in the end, it is the same quantity.

physics
1:1

physics
same thing.

Science Ecology
Your answer is fine. I would mark it 3.9 on a 4.0 scale Second question: Understand the concept, and how to apply it. The application demonstrates understanding. You can do this by making note cards, writing, teaching other kids. Have you ever has a study buddy?

american history
In my opinion, what drove the impulse was religion reawakening...a belief in a higher power, or a higher goal for "goodness"

Sign Language
correct

Chemistry
Mass Number= protons+neutrons=33+35

Psychology
dependent variable: score on choosing anagrams. Independent variable: relaxing, reading, or anagram work.

History
d. They wanted control of the rail lines out of Memphis, but they achieved that by Attacking near Corinth Mississippi, which was a junction for that rail system.

Chemistry
Ba++ + SO4-- >> BaSO4 (s)

Chemistry
Consider the following acids: HF HCl HBr

Physics
a. torque=28(.84)*sin90 Nm b. torque=28(.84)*sin45 Nm c. Torque=28*.84*sin0 so it is the product of force times length* sine of angle between force and door.

Math [Algebra]
His error was not to use grouping symbols. (4x-8x)/2=-2x 4x -(8x/2)=zero

math
yes, standard form for a polynomial can have more than three forms. http://www.mathwarehouse.com/dictionary/S-words/definition-of-standard-form-of-a-polynomial.php your second example, no, that is not standard form.

Sociology
changing climate=>heating>heat being held in the ecosphere>carbondioxide.

Physics
breaks this up into time slots, first to last. Then plot it on a graph velocity vs time. Acceleration is the slope of the graph. how far: distance is the area under the velocity/time graph. You can estimate that on the graph.

Physics
one has to know the mass of the block.

Physics
v = c*sqrt(1 - ((0.511*10^6)(3.00*10^8m/s)^2)/651000)^2 now examine the units mass in particular =c*sqrt(1 - ((0.511*10^6ev/c^2)*(c)^2)/651000ev)^2 =c*sqrt(1 - ((0.511*10^6ev/c^2)*(c)^2)/651000ev)^2 =c*sqrt(1 - ((0.511*10^6ev)^2)/651000ev)^2 =c(sqrt(1-(.511e6/65100)^2) check ...

Algebra
so the question is when is interest compounded? annually, daily, monthly? every 10th of the year? It matters.

Physics
Threshold energy=e*c/lamda dimensions are a red herring here.

Caluclus
7x+1y?5=0 y=-7x+5 so the distance minimum will be on a line thru the point (-2,6) and has a slope of 1/7 y=1/7 x+b -2=1/7 (-2)+b b=-2+2/7 now look at the lines to find the intersection. y=-7x+5 y=x/7 -2+2/7 set them equal -7x+5=x/7-2+2/7 solve for x, then go back and solve ...

physical science
and B

Physics
x=Asinwt v=Aw*coswt a=Aw^2sinwt a) v=A*2PI*f recommend change Amplitude to m. b) a=A*(2PIf)^2

Physics
beat frequencies, add them, and subtract them. subtract=894-686=...that is often what we mean on beat freq. add=add them, this is the second beat frequency.

Social Studies
After the revival of temperance interest in the 1840s, a second prohibition effort occurred in the next decade. The state of Maine, under the efforts of the merchant Neal Dow, passed a prohibitory statute in 1851 outlawing the manufacture and sale of intoxicants. The Maine Law...

Chemistry
Nope, affinity forms more negative ions. Se++ + e- >>Se+

Social Studies

Math
what is 1/4 + 2/5 ?

Maths
wondering if the lowest cone is truncated?

Pay attention to this thread. In the real world, a real teacher would be paying attention to this kid. What are you doing?

I think you should congradulate me: I am encouraging you to fail, and take responsibility for your own life. I can't do it, your mom can't do it, grammy can't, and dad can't. Ask yourself how did you get into this pickle, no one else did it. If you think you ...

Science

Science
mutagens in the environment, mutation rate, sources and availability of food for that species, changes in the enviroment, safety from disease and predators. Ability to reproduce.

General Chemistry
7.5 min. each 10Kelvins doubles reaction rate, as a rule of thumb for first order reacxtions , you can work it more precisely here: https://socratic.org/questions/a-first-order-reaction-is-50-completed-after-30-minutes-this-implies-that-the-ti for the rule of thumb, and you ...

MATH HELP ME PLZZ
2/3 B=P 2/3 *2469=P solve for P

chemistry
work it in two parts. let V be the volume of H2 produced in the CaH2 reaction, and 1.2-V be the volume in the LiH reaction. Let m be mass in the CaH2 reaction, and .850g -m be the mass in the LiH reaction. You will get two equations, one unknown out of this. CaH2 reaction: ...

chemsitry
what is Pressure*volume? 85.9*2.5*101kPa*dm^3== 21689750e-6 Pa*L^3 but what is a Pa? force/m^2=N/m^2 so Pa*m^3=Joules PV=21.7Joules

character education
B for me, and last one, C (for me). I ask always...what would Jesus do? A reflection. But current research leans heavily to B..http://subcortex.com/PrinzEmotionalBasisMoralJudgments.pdf

Art
aren't the waves in lines? https://www.google.com/culturalinstitute/beta/asset/the-wounded-foot/BQEbLkbXG19YSQ?hl=en&ms=%7B%22x%22%3A0.5%2C%22y%22%3A0.5%2C%22z%22%3A8.375262753582142%2C%22size%22%3A%7B%22width%22%3A2.9107861733319664%2C%22height%22%3A1.2374999999999994%7D%7D

Damon/BobPursley/Physicstutor/whichoneisright
I see the table is formatted wrong 10m/s >8m 20m/s >32m 40m/s >128m so the question is: what is the stopping distance at 32m/s if it takes .6sec to hit the brakes? distance=constant*v^2 From the table: 8=constant*10^2 constant=.08 now try it for 20 distance=.08*20^2=...

physics
E is uniform? then force is Eq, and is downward. force gravity=9.8 force electric=5e-6*E total acceleration down=totalforce/mass at the top, vfinal=zero vf=vi+at where t=2.05sec you know vi, t, solve for a. With that a, set it equal to totalforce/mass and solve for E. Voltage=...

Sociology
Nuts to that answer. Do you read your text? The form of marriage and family has changed over time, and it will continue to evolve. Based on social trends and research conducted by sociologists, some predictions about family life can be made: -marriage will continue because it ...

physics
Yes, as I understand what you are saying, you are right if your "uncertainity" is in absolute numbers. Remember, it is not possible to add 34 and .00005 . the website is pretty clear on the division rule. Something is very wrong if you can't see that in the text ...

physics
Honestly, you need to learn it, and not have someone tell you. You add and subtract, per this http://web.uvic.ca/~jalexndr/192UncertRules.pdf

Physics
distance=constant*v^2 32=constant*10^2 constant=.32 now try it for 20 distance=.32*20^2=128, so you have the formula. So at 30m/s, distance=.32*30^2=288 now you have to add the distance traveled before breaking, 30*.6=18m total distance=18+288 m. The72 m is bogus.

Science
convection is carried by molecules, radiation by light waves.

science
There is something here missing.

PHYSICS
force=q*VB sintheta where theta is the angle between V and B. accleeration= force/mass

Chemistry
loses 2 protons, 2 neutrons so atomic number goes from 3 to 1, and atomic mass goes from 7 to 3. Tritium is left. 1H3

Physics
oops, add a PI in the denominator of the law of continuity, area=pI*radius^2

Physics
lAW OF CONTINUITY: area1*speed1=area2*speed2 speednarrow=PI(6^2)*.380/(.350^2) volume flow rate=speed*area do that for both sides.

character education
nope. Do you ever search terms for meaning? <<Kant's improvement on the golden rule, the Categorical Imperative: Act as you would want all other people to act towards all other people. Act according to the maxim that you would wish all other rational people to follow...

Physics
flow rate-3500gal/14hrs*1hr/60min time= volume/rate=11,000/(3500/840) gal/min

physics
what is 100-80.99 ?

Sculpturing Earth's Surface
b is not correct.

Biology
The vial with 20 flies will experience greater sampling error and thus more genetic drift than the vial with 200 flies, so the vial with 20 flies has probably fixed/lost more alleles than the fly vial with 200 individuals. Genetic variation has thus decreased within each ...

Sculpturing Earth's Surface
Goodness no. C. How can you miss what I posted.

Sculpturing Earth's Surface
Water that falls as precipitation flows along the surface of the ground. This surface water infiltrates into the ground surface and is held in soil pore spaces and in the fractures of rock formations. Gaining access to groundwater sources therefore requires digging or drilling...

Sociology
Nope, check spelling on Principal.

Sociology
nope, that would be most unusual. Are newborn babies leaders of the family?

character education
sanc·tion ?saNG(k)SH(?)n/ noun plural noun: sanctions 1. a threatened penalty for disobeying a law or rule. "a range of sanctions aimed at deterring insider abuse" synonyms: penalty, punishment, deterrent; More punitive action, discipline, restriction; embargo...

physics
Magnification=anglesubteded when viewingMicrosocope/angle with naked eye)

physics
what is 145x5E-3 ?

Physics help
My work on this would be meaningless without a sketch (and assumed directons of forces). Take a look at this sample problem http://physicstasks.eu/654/a-leaning-ladder

As Physics
I also suggest any of these basic concept books: They should be available in the UK. https://www.amazon.com/Physics-Dummies-Math-Science/dp/1119293596

Algebra
objective: get y alone. 1) multiply both sides by 3 y-5=3 add 5 to each side y=8

unit 3: Lesson 8: Interaction of Forces Unit Test
terrible question. Motion is the best answer, the fan is turning.

Math
log10(A)=ln(A)/ln(10)= ln(A)/2.303 The opposite: ln(A)=2.303*Log10(A)

Algebra 1b help
correct

As physics
You are missing the point. Conservation of Momentum applies, that is the point. for the system: initial momentum=final momentum .25*.2+.25*0=(.25+.25)V V=.1m/s

As physics
a. Conservation of momentum applies. 5E4*2.50=(5E4+4E4)V solve for V b. change in KE= initial KE-final KE = 1/2 *5E4*(2.5)^2 -(1/2)(5E4+4E4)V^2 so if you get any number, there was a change in KE, and it is inelastic. <<Use the equations above only do not use any other ...

Science
No text? No notes? a. repel, attract b. a positive charge c. opposite the

character education
I agree.

Writing
https://www.grammarly.com/ is a free grammar checker, I recommend it.

Writing
we can try it, formatting is difficult here.

Math
(360+S)/5=70 so S=360-350 which means he can get as low as -10 and get a 70 average. Now his teacher may not give minus scores, so he can score zero to 100 and get his 70 average.

Physics
heat=masswater*specificheatwater*38 but heat=19kiloton*4.2E12J/kiloton so if you set them equal, and for c use units of J/kgC, solve for mass.

math
If there is an even number of items in the data set, then the median is found by taking the mean (average) of the two middlemost numbers. 54,56,58,60,62,64,66,68

Algebra
f(x)=- x2 +8x – 12 =-(x^2-8x+16)+4 = -(x-4)^2 +4 on the second, I assume you meant (-6i)2 (-1^2 * 6^2 * i^2)=-36

Math
I think he meant this (n/-3 )+5>4 multiply by -3 n-15>-12 n>3

Physics
Wouldn't that depend on the level? A, or B? https://www.google.com/search?q=What+are+all+the+OCR+physics+equations+you+have+to+memorise&ie=utf-8&oe=utf-8&client=firefox-b-1

ELA
I think b) the infinitive to play is the object of the verb wants. d) the infinitive to study is an adverb modifying the verb met. choice D is the best choice of the four. http://www.chompchomp.com/terms/infinitivephrase.htm applies.

algebra
distance=avg speed*time 50km/hr*9hr=avgspeedPlane*1hr avgspeedPlane=450km/hr

algebra
reiny is correct, my rate for AandC has an error.

algebra
rateA&B=1/10+1/8=18/80=9/40 rateA&c=1/8 +1/12=20/72=10/36 A. How much of the task is done in the first hour? rate*time=9/40*1=9/40 then how long after the first hour? time=amountoftaskLeft/rate=(31/40)/(10/36)= 36*31/40*10=2.79 hours more how long= 1+2.79 hours

U.S. History
https://www.bostonteapartyship.com/boston-non-importation-agreement Smuggling and self-reliance were rampant.

physics
g=v^2/r solve for v. g=9.8m/s^2

math
prime factorization:made up of primes, each to some power. In this case, 2,3,5,11 are primes, but 8 is not, it is 2^3, so prime factorization should be 2^5 * 3 *5^4 *11^2

pre calc
a. Both have the exact same shape of curve, that is, except for position. Derivative means the function which defines the slope at any x, and both functions are the same. go to your definition of derative.\ Lim d>0 of (f(x+d)-f(x))/d = Lim d>0 of ((x+d)^4 -x^4)/d = lim d...

Chemistry
of course the answer is not for this problem, you have to put in the numbers with this problem and solve it. That is a sample of how it is to be solved.

Chemistry

Physics
For observer and source both moving: fobserver=fsource [(1+ or - vobserver/v)/(1+ or -vsource/v)] v= velocity of sound in air signs in numerator: + if observer moving toward source and - if away from source signs in denominator: - if source moving toward observer and + if away...

poetry and creative writing
description: art and craft boutique of jewelry, paintings, what nots, etc. every corner and nook a surprise with colors and shapes galore. Found in the back we also realize a door leading to more.

physics
draw a sketch of the cyclist. notice from her center of gravity, a horizontal force (centripetal force) of mv^2/r the vertical force is mg so tan Theta= mv^2/mgr=v^2/gr now, the numbers v=72km/hr=20m/s (how convenient ) , and r=80 tanTheta=20^2/9.8*80=.51 theta=arctan(.51)

Math
S=sqrt(30*D*f*n) s^2=30*D*f*n d=70^2/(30*.5*.85) about 385 feet. check that

Science
power=work/time time(in seconds)=workinJoules/powerinWatts time= 727joules/1225watts= about half a second.

Chemistry 131
freezingpt=-l.86*2*4/molmass*1/.1 molmass=l.86*8*10/1.28=116.3 mass of K is 39 so atomic mass of halide is 77, potassium bromide. do the math a little more carefully than I did in my head.

Biology
correct

Chemistry
2H2+O2>>>2H2O four moles of H2 produces 4moles water 4moles water=4*18grams water

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